[PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[Eliav Farber]

This series backports 27 patches to update minmax.h in the 5.10.y
branch, aligning it with v6.17-rc7.

The ultimate goal is to synchronize all long-term branches so that they
include the full set of minmax.h changes.

- 6.12.y has already been backported; the changes are included in
  v6.12.49.
- 6.6.y has already been backported; the changes are included in
  v6.6.109.
- 6.1.y has already been backported; the changes are currently in the
  6.1-stable tree.
- 5.15.y has already been backported; the changes are currently in the
  5.15-stable tree.

The key motivation is to bring in commit d03eba99f5bf ("minmax: allow
min()/max()/clamp() if the arguments have the same signedness"), which
is missing in kernel 5.10.y.

In mainline, this change enables min()/max()/clamp() to accept mixed
argument types, provided both have the same signedness. Without it,
backported patches that use these forms may trigger compiler warnings,
which escalate to build failures when -Werror is enabled.

The first two patches in this series were added to prevent build
failures caused by changes introduced later in minmax.h.

 - Commit 92d23c6e9415 ("overflow, tracing: Define the is_signed_type()
   macro once") is needed for commit 75ca38c1960f ("minmax: allow
   min()/max()/clamp()").

 - Commit cea628008fc8 ("btrfs: remove duplicated in_range() macro") is
   needed for commit f9bff0e31881 ("minmax: add in_range() macro").

The changes were tested using `make allyesconfig` and
`make allmodconfig` for arm64, arm, x86_64 and i386 architectures.

Changes in v2:
The series was updated after initially backporting and approving the
newer long-term branches.

Andy Shevchenko (2):
  minmax: deduplicate __unconst_integer_typeof()
  minmax: fix header inclusions

Bart Van Assche (1):
  overflow, tracing: Define the is_signed_type() macro once

David Laight (11):
  minmax: allow min()/max()/clamp() if the arguments have the same
    signedness.
  minmax: fix indentation of __cmp_once() and __clamp_once()
  minmax: allow comparisons of 'int' against 'unsigned char/short'
  minmax: relax check to allow comparison between unsigned arguments and
    signed constants
  minmax.h: add whitespace around operators and after commas
  minmax.h: update some comments
  minmax.h: reduce the #define expansion of min(), max() and clamp()
  minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()
  minmax.h: move all the clamp() definitions after the min/max() ones
  minmax.h: simplify the variants of clamp()
  minmax.h: remove some #defines that are only expanded once

Herve Codina (1):
  minmax: Introduce {min,max}_array()

Jason A. Donenfeld (2):
  minmax: sanity check constant bounds when clamping
  minmax: clamp more efficiently by avoiding extra comparison

Johannes Thumshirn (1):
  btrfs: remove duplicated in_range() macro

Linus Torvalds (8):
  minmax: avoid overly complicated constant expressions in VM code
  minmax: add a few more MIN_T/MAX_T users
  minmax: simplify and clarify min_t()/max_t() implementation
  minmax: make generic MIN() and MAX() macros available everywhere
  minmax: don't use max() in situations that want a C constant
    expression
  minmax: simplify min()/max()/clamp() implementation
  minmax: improve macro expansion and type checking
  minmax: fix up min3() and max3() too

Matthew Wilcox (Oracle) (1):
  minmax: add in_range() macro

 arch/arm/mm/pageattr.c                        |   6 +-
 arch/um/drivers/mconsole_user.c               |   2 +
 arch/x86/mm/pgtable.c                         |   2 +-
 drivers/edac/sb_edac.c                        |   4 +-
 drivers/edac/skx_common.h                     |   1 -
 .../drm/amd/display/modules/hdcp/hdcp_ddc.c   |   2 +
 .../drm/amd/pm/powerplay/hwmgr/ppevvmath.h    |  14 +-
 .../drm/arm/display/include/malidp_utils.h    |   2 +-
 .../display/komeda/komeda_pipeline_state.c    |  24 +-
 drivers/gpu/drm/drm_color_mgmt.c              |   2 +-
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c         |   6 -
 drivers/gpu/drm/radeon/evergreen_cs.c         |   2 +
 drivers/hwmon/adt7475.c                       |  24 +-
 drivers/input/touchscreen/cyttsp4_core.c      |   2 +-
 drivers/md/dm-integrity.c                     |   6 +-
 drivers/media/dvb-frontends/stv0367_priv.h    |   3 +
 .../net/ethernet/chelsio/cxgb3/cxgb3_main.c   |  18 +-
 .../net/ethernet/stmicro/stmmac/stmmac_main.c |   2 +-
 drivers/net/fjes/fjes_main.c                  |   4 +-
 drivers/nfc/pn544/i2c.c                       |   2 -
 drivers/platform/x86/sony-laptop.c            |   1 -
 drivers/scsi/isci/init.c                      |   6 +-
 .../pci/hive_isp_css_include/math_support.h   |   5 -
 fs/btrfs/ctree.h                              |   2 -
 fs/btrfs/extent_io.c                          |   1 +
 fs/btrfs/file-item.c                          |   1 +
 fs/btrfs/misc.h                               |   2 -
 fs/btrfs/raid56.c                             |   1 +
 fs/btrfs/tree-checker.c                       |   2 +-
 fs/erofs/zdata.h                              |   2 +-
 fs/ext2/balloc.c                              |   2 -
 fs/ext4/ext4.h                                |   2 -
 fs/ufs/util.h                                 |   6 -
 include/linux/compiler.h                      |  15 +
 include/linux/minmax.h                        | 267 ++++++++++++++----
 include/linux/overflow.h                      |   1 -
 include/linux/trace_events.h                  |   2 -
 kernel/trace/preemptirq_delay_test.c          |   2 -
 lib/btree.c                                   |   1 -
 lib/decompress_unlzma.c                       |   2 +
 lib/logic_pio.c                               |   3 -
 lib/vsprintf.c                                |   2 +-
 lib/zstd/zstd_internal.h                      |   2 -
 mm/zsmalloc.c                                 |   1 -
 net/ipv4/proc.c                               |   2 +-
 net/ipv6/proc.c                               |   2 +-
 net/netfilter/nf_nat_core.c                   |   6 +-
 net/tipc/core.h                               |   2 +-
 net/tipc/link.c                               |  10 +-
 49 files changed, 312 insertions(+), 169 deletions(-)

-- 
2.47.3

[PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once

[Eliav Farber]

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]

There are two definitions of the is_signed_type() macro: one in
<linux/overflow.h> and a second definition in <linux/trace_events.h>.

As suggested by Linus Torvalds, move the definition of the
is_signed_type() macro into the <linux/compiler.h> header file. Change
the definition of the is_signed_type() macro to make sure that it does
not trigger any sparse warnings with future versions of sparse for
bitwise types. See also:
https://lore.kernel.org/all/CAHk-=whjH6p+qzwUdx5SOVVHjS3WvzJQr6mDUwhEyTf6pJWzaQ@mail.gmail.com/
https://lore.kernel.org/all/CAHk-=wjQGnVfb4jehFR0XyZikdQvCZouE96xR_nnf5kqaM5qqQ@mail.gmail.com/

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Isabella Basso <isabbasso@riseup.net>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sander Vanheule <sander@svanheule.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220826162116.1050972-3-bvanassche@acm.org
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/compiler.h     | 6 ++++++
 include/linux/overflow.h     | 1 -
 include/linux/trace_events.h | 2 --
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index bbd74420fa21..004a030d5ad2 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -245,6 +245,12 @@ static inline void *offset_to_ptr(const int *off)
 /* &a[0] degrades to a pointer: a different type from an array */
 #define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
 
+/*
+ * Whether 'type' is a signed type or an unsigned type. Supports scalar types,
+ * bool and also pointer types.
+ */
+#define is_signed_type(type) (((type)(-1)) < (__force type)1)
+
 /*
  * This is needed in functions which generate the stack canary, see
  * arch/x86/kernel/smpboot.c::start_secondary() for an example.
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 73bc67ec2136..e6bf14f462e9 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -29,7 +29,6 @@
  * https://mail-index.netbsd.org/tech-misc/2007/02/05/0000.html -
  * credit to Christian Biere.
  */
-#define is_signed_type(type)       (((type)(-1)) < (type)1)
 #define __type_half_max(type) ((type)1 << (8*sizeof(type) - 1 - is_signed_type(type)))
 #define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T)))
 #define type_min(T) ((T)((T)-type_max(T)-(T)1))
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 5af2acb9fb7d..0c8c3cf36f96 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -700,8 +700,6 @@ extern int trace_add_event_call(struct trace_event_call *call);
 extern int trace_remove_event_call(struct trace_event_call *call);
 extern int trace_event_get_offsets(struct trace_event_call *call);
 
-#define is_signed_type(type)	(((type)(-1)) < (type)1)
-
 int ftrace_set_clr_event(struct trace_array *tr, char *buf, int set);
 int trace_set_clr_event(const char *system, const char *event, int set);
 int trace_array_set_clr_event(struct trace_array *tr, const char *system,
-- 
2.47.3

[PATCH v2 02/27 5.10.y] btrfs: remove duplicated in_range() macro

[Eliav Farber]

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>

[ Upstream commit cea628008fc8c6c9c7b53902f6659e040f33c790 ]

The in_range() macro is defined twice in btrfs' source, once in ctree.h
and once in misc.h.

Remove the definition in ctree.h and include misc.h in the files depending
on it.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 fs/btrfs/ctree.h     | 2 --
 fs/btrfs/extent_io.c | 1 +
 fs/btrfs/file-item.c | 1 +
 fs/btrfs/raid56.c    | 1 +
 4 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index d9d6a57acafe..a9926fb10c49 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3597,8 +3597,6 @@ static inline int btrfs_defrag_cancelled(struct btrfs_fs_info *fs_info)
 	return signal_pending(current);
 }
 
-#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
-
 /* Sanity test specific functions */
 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 void btrfs_test_destroy_inode(struct inode *inode);
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 8498994ef5c6..489d370ddd60 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -13,6 +13,7 @@
 #include <linux/pagevec.h>
 #include <linux/prefetch.h>
 #include <linux/cleancache.h>
+#include "misc.h"
 #include "extent_io.h"
 #include "extent-io-tree.h"
 #include "extent_map.h"
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index cbea4f572155..6e46da3ee433 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -9,6 +9,7 @@
 #include <linux/highmem.h>
 #include <linux/sched/mm.h>
 #include <crypto/hash.h>
+#include "misc.h"
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 9678d7fa4dcc..ed3e40a4a3cb 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -13,6 +13,7 @@
 #include <linux/list_sort.h>
 #include <linux/raid/xor.h>
 #include <linux/mm.h>
+#include "misc.h"
 #include "ctree.h"
 #include "disk-io.h"
 #include "volumes.h"
-- 
2.47.3

[PATCH v2 03/27 5.10.y] minmax: sanity check constant bounds when clamping

[Eliav Farber]

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

[ Upstream commit 5efcecd9a3b18078d3398b359a84c83f549e22cf ]

The clamp family of functions only makes sense if hi>=lo.  If hi and lo
are compile-time constants, then raise a build error.  Doing so has
already caught buggy code.  This also introduces the infrastructure to
improve the clamping function in subsequent commits.

[akpm@linux-foundation.org: coding-style cleanups]
[akpm@linux-foundation.org: s@&&\@&& \@]
Link: https://lkml.kernel.org/r/20220926133435.1333846-1-Jason@zx2c4.com
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 1aea34b8f19b..8b092c66c5aa 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -37,6 +37,28 @@
 		__cmp(x, y, op), \
 		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
 
+#define __clamp(val, lo, hi)	\
+	__cmp(__cmp(val, lo, >), hi, <)
+
+#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({	\
+		typeof(val) unique_val = (val);				\
+		typeof(lo) unique_lo = (lo);				\
+		typeof(hi) unique_hi = (hi);				\
+		__clamp(unique_val, unique_lo, unique_hi); })
+
+#define __clamp_input_check(lo, hi)					\
+        (BUILD_BUG_ON_ZERO(__builtin_choose_expr(			\
+                __is_constexpr((lo) > (hi)), (lo) > (hi), false)))
+
+#define __careful_clamp(val, lo, hi) ({					\
+	__clamp_input_check(lo, hi) +					\
+	__builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) && \
+			      __typecheck(hi, lo) && __is_constexpr(val) && \
+			      __is_constexpr(lo) && __is_constexpr(hi),	\
+		__clamp(val, lo, hi),					\
+		__clamp_once(val, lo, hi, __UNIQUE_ID(__val),		\
+			     __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
+
 /**
  * min - return minimum of two values of the same or compatible types
  * @x: first value
@@ -103,7 +125,7 @@
  * This macro does strict typechecking of @lo/@hi to make sure they are of the
  * same type as @val.  See the unnecessary pointer comparisons.
  */
-#define clamp(val, lo, hi) min((typeof(val))max(val, lo), hi)
+#define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
 
 /*
  * ..and if you can't take the strict
@@ -138,7 +160,7 @@
  * This macro does no typechecking and uses temporary variables of type
  * @type to make all the comparisons.
  */
-#define clamp_t(type, val, lo, hi) min_t(type, max_t(type, val, lo), hi)
+#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
 
 /**
  * clamp_val - return a value clamped to a given range using val's type
-- 
2.47.3

[PATCH v2 04/27 5.10.y] minmax: clamp more efficiently by avoiding extra comparison

[Eliav Farber]

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

[ Upstream commit 2122e2a4efc2cd139474079e11939b6e07adfacd ]

Currently the clamp algorithm does:

    if (val > hi)
        val = hi;
    if (val < lo)
        val = lo;

But since hi > lo by definition, this can be made more efficient with:

    if (val > hi)
        val = hi;
    else if (val < lo)
        val = lo;

So fix up the clamp and clamp_t functions to do this, adding the same
argument checking as for min and min_t.

For simple cases, code generation on x86_64 and aarch64 stay about the
same:

    before:
            cmp     edi, edx
            mov     eax, esi
            cmova   edi, edx
            cmp     edi, esi
            cmovnb  eax, edi
            ret
    after:
            cmp     edi, esi
            mov     eax, edx
            cmovnb  esi, edi
            cmp     edi, edx
            cmovb   eax, esi
            ret

    before:
            cmp     w0, w2
            csel    w8, w0, w2, lo
            cmp     w8, w1
            csel    w0, w8, w1, hi
            ret
    after:
            cmp     w0, w1
            csel    w8, w0, w1, hi
            cmp     w0, w2
            csel    w0, w8, w2, lo
            ret

On MIPS64, however, code generation improves, by removing arithmetic in
the second branch:

    before:
            sltu    $3,$6,$4
            bne     $3,$0,.L2
            move    $2,$6

            move    $2,$4
    .L2:
            sltu    $3,$2,$5
            bnel    $3,$0,.L7
            move    $2,$5

    .L7:
            jr      $31
            nop
    after:
            sltu    $3,$4,$6
            beq     $3,$0,.L13
            move    $2,$6

            sltu    $3,$4,$5
            bne     $3,$0,.L12
            move    $2,$4

    .L13:
            jr      $31
            nop

    .L12:
            jr      $31
            move    $2,$5

For more complex cases with surrounding code, the effects are a bit
more complicated. For example, consider this simplified version of
timestamp_truncate() from fs/inode.c on x86_64:

    struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode)
    {
        struct super_block *sb = inode->i_sb;
        unsigned int gran = sb->s_time_gran;

        t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max);
        if (t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min)
            t.tv_nsec = 0;
        return t;
    }

    before:
            mov     r8, rdx
            mov     rdx, rsi
            mov     rcx, QWORD PTR [r8]
            mov     rax, QWORD PTR [rcx+8]
            mov     rcx, QWORD PTR [rcx+16]
            cmp     rax, rdi
            mov     r8, rcx
            cmovge  rdi, rax
            cmp     rdi, rcx
            cmovle  r8, rdi
            cmp     rax, r8
            je      .L4
            cmp     rdi, rcx
            jge     .L4
            mov     rax, r8
            ret
    .L4:
            xor     edx, edx
            mov     rax, r8
            ret

    after:
            mov     rax, QWORD PTR [rdx]
            mov     rdx, QWORD PTR [rax+8]
            mov     rax, QWORD PTR [rax+16]
            cmp     rax, rdi
            jg      .L6
            mov     r8, rax
            xor     edx, edx
    .L2:
            mov     rax, r8
            ret
    .L6:
            cmp     rdx, rdi
            mov     r8, rdi
            cmovge  r8, rdx
            cmp     rax, r8
            je      .L4
            xor     eax, eax
            cmp     rdx, rdi
            cmovl   rax, rsi
            mov     rdx, rax
            mov     rax, r8
            ret
    .L4:
            xor     edx, edx
            jmp     .L2

In this case, we actually gain a branch, unfortunately, because the
compiler's replacement axioms no longer as cleanly apply.

So all and all, this change is a bit of a mixed bag.

Link: https://lkml.kernel.org/r/20220926133435.1333846-2-Jason@zx2c4.com
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 8b092c66c5aa..abdeae409dad 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -38,7 +38,7 @@
 		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
 
 #define __clamp(val, lo, hi)	\
-	__cmp(__cmp(val, lo, >), hi, <)
+	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
 
 #define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({	\
 		typeof(val) unique_val = (val);				\
-- 
2.47.3

[PATCH v2 05/27 5.10.y] minmax: add in_range() macro

[Eliav Farber]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

[ Upstream commit f9bff0e31881d03badf191d3b0005839391f5f2b ]

Patch series "New page table range API", v6.

This patchset changes the API used by the MM to set up page table entries.
The four APIs are:

    set_ptes(mm, addr, ptep, pte, nr)
    update_mmu_cache_range(vma, addr, ptep, nr)
    flush_dcache_folio(folio)
    flush_icache_pages(vma, page, nr)

flush_dcache_folio() isn't technically new, but no architecture
implemented it, so I've done that for them.  The old APIs remain around
but are mostly implemented by calling the new interfaces.

The new APIs are based around setting up N page table entries at once.
The N entries belong to the same PMD, the same folio and the same VMA, so
ptep++ is a legitimate operation, and locking is taken care of for you.
Some architectures can do a better job of it than just a loop, but I have
hesitated to make too deep a change to architectures I don't understand
well.

One thing I have changed in every architecture is that PG_arch_1 is now a
per-folio bit instead of a per-page bit when used for dcache clean/dirty
tracking.  This was something that would have to happen eventually, and it
makes sense to do it now rather than iterate over every page involved in a
cache flush and figure out if it needs to happen.

The point of all this is better performance, and Fengwei Yin has measured
improvement on x86.  I suspect you'll see improvement on your architecture
too.  Try the new will-it-scale test mentioned here:
https://lore.kernel.org/linux-mm/20230206140639.538867-5-fengwei.yin@intel.com/
You'll need to run it on an XFS filesystem and have
CONFIG_TRANSPARENT_HUGEPAGE set.

This patchset is the basis for much of the anonymous large folio work
being done by Ryan, so it's received quite a lot of testing over the last
few months.

This patch (of 38):

Determine if a value lies within a range more efficiently (subtraction +
comparison vs two comparisons and an AND).  It also has useful (under some
circumstances) behaviour if the range exceeds the maximum value of the
type.  Convert all the conflicting definitions of in_range() within the
kernel; some can use the generic definition while others need their own
definition.

Link: https://lkml.kernel.org/r/20230802151406.3735276-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230802151406.3735276-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 arch/arm/mm/pageattr.c                        |  6 ++---
 .../drm/arm/display/include/malidp_utils.h    |  2 +-
 .../display/komeda/komeda_pipeline_state.c    | 24 ++++++++---------
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c         |  6 -----
 .../net/ethernet/chelsio/cxgb3/cxgb3_main.c   | 18 ++++++-------
 fs/btrfs/misc.h                               |  2 --
 fs/ext2/balloc.c                              |  2 --
 fs/ext4/ext4.h                                |  2 --
 fs/ufs/util.h                                 |  6 -----
 include/linux/minmax.h                        | 27 +++++++++++++++++++
 lib/logic_pio.c                               |  3 ---
 net/netfilter/nf_nat_core.c                   |  6 ++---
 net/tipc/core.h                               |  2 +-
 net/tipc/link.c                               | 10 +++----
 14 files changed, 61 insertions(+), 55 deletions(-)

diff --git a/arch/arm/mm/pageattr.c b/arch/arm/mm/pageattr.c
index 9790ae3a8c68..3b3bfa825fad 100644
--- a/arch/arm/mm/pageattr.c
+++ b/arch/arm/mm/pageattr.c
@@ -25,7 +25,7 @@ static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
 	return 0;
 }
 
-static bool in_range(unsigned long start, unsigned long size,
+static bool range_in_range(unsigned long start, unsigned long size,
 	unsigned long range_start, unsigned long range_end)
 {
 	return start >= range_start && start < range_end &&
@@ -46,8 +46,8 @@ static int change_memory_common(unsigned long addr, int numpages,
 	if (!size)
 		return 0;
 
-	if (!in_range(start, size, MODULES_VADDR, MODULES_END) &&
-	    !in_range(start, size, VMALLOC_START, VMALLOC_END))
+	if (!range_in_range(start, size, MODULES_VADDR, MODULES_END) &&
+	    !range_in_range(start, size, VMALLOC_START, VMALLOC_END))
 		return -EINVAL;
 
 	data.set_mask = set_mask;
diff --git a/drivers/gpu/drm/arm/display/include/malidp_utils.h b/drivers/gpu/drm/arm/display/include/malidp_utils.h
index 49a1d7f3539c..9f83baac6ed8 100644
--- a/drivers/gpu/drm/arm/display/include/malidp_utils.h
+++ b/drivers/gpu/drm/arm/display/include/malidp_utils.h
@@ -35,7 +35,7 @@ static inline void set_range(struct malidp_range *rg, u32 start, u32 end)
 	rg->end   = end;
 }
 
-static inline bool in_range(struct malidp_range *rg, u32 v)
+static inline bool malidp_in_range(struct malidp_range *rg, u32 v)
 {
 	return (v >= rg->start) && (v <= rg->end);
 }
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
index 7cc891c091f8..3e414d2fbdda 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_pipeline_state.c
@@ -305,12 +305,12 @@ komeda_layer_check_cfg(struct komeda_layer *layer,
 	if (komeda_fb_check_src_coords(kfb, src_x, src_y, src_w, src_h))
 		return -EINVAL;
 
-	if (!in_range(&layer->hsize_in, src_w)) {
+	if (!malidp_in_range(&layer->hsize_in, src_w)) {
 		DRM_DEBUG_ATOMIC("invalidate src_w %d.\n", src_w);
 		return -EINVAL;
 	}
 
-	if (!in_range(&layer->vsize_in, src_h)) {
+	if (!malidp_in_range(&layer->vsize_in, src_h)) {
 		DRM_DEBUG_ATOMIC("invalidate src_h %d.\n", src_h);
 		return -EINVAL;
 	}
@@ -452,14 +452,14 @@ komeda_scaler_check_cfg(struct komeda_scaler *scaler,
 	hsize_out = dflow->out_w;
 	vsize_out = dflow->out_h;
 
-	if (!in_range(&scaler->hsize, hsize_in) ||
-	    !in_range(&scaler->hsize, hsize_out)) {
+	if (!malidp_in_range(&scaler->hsize, hsize_in) ||
+	    !malidp_in_range(&scaler->hsize, hsize_out)) {
 		DRM_DEBUG_ATOMIC("Invalid horizontal sizes");
 		return -EINVAL;
 	}
 
-	if (!in_range(&scaler->vsize, vsize_in) ||
-	    !in_range(&scaler->vsize, vsize_out)) {
+	if (!malidp_in_range(&scaler->vsize, vsize_in) ||
+	    !malidp_in_range(&scaler->vsize, vsize_out)) {
 		DRM_DEBUG_ATOMIC("Invalid vertical sizes");
 		return -EINVAL;
 	}
@@ -574,13 +574,13 @@ komeda_splitter_validate(struct komeda_splitter *splitter,
 		return -EINVAL;
 	}
 
-	if (!in_range(&splitter->hsize, dflow->in_w)) {
+	if (!malidp_in_range(&splitter->hsize, dflow->in_w)) {
 		DRM_DEBUG_ATOMIC("split in_w:%d is out of the acceptable range.\n",
 				 dflow->in_w);
 		return -EINVAL;
 	}
 
-	if (!in_range(&splitter->vsize, dflow->in_h)) {
+	if (!malidp_in_range(&splitter->vsize, dflow->in_h)) {
 		DRM_DEBUG_ATOMIC("split in_h: %d exceeds the acceptable range.\n",
 				 dflow->in_h);
 		return -EINVAL;
@@ -624,13 +624,13 @@ komeda_merger_validate(struct komeda_merger *merger,
 		return -EINVAL;
 	}
 
-	if (!in_range(&merger->hsize_merged, output->out_w)) {
+	if (!malidp_in_range(&merger->hsize_merged, output->out_w)) {
 		DRM_DEBUG_ATOMIC("merged_w: %d is out of the accepted range.\n",
 				 output->out_w);
 		return -EINVAL;
 	}
 
-	if (!in_range(&merger->vsize_merged, output->out_h)) {
+	if (!malidp_in_range(&merger->vsize_merged, output->out_h)) {
 		DRM_DEBUG_ATOMIC("merged_h: %d is out of the accepted range.\n",
 				 output->out_h);
 		return -EINVAL;
@@ -866,8 +866,8 @@ void komeda_complete_data_flow_cfg(struct komeda_layer *layer,
 	 * input/output range.
 	 */
 	if (dflow->en_scaling && scaler)
-		dflow->en_split = !in_range(&scaler->hsize, dflow->in_w) ||
-				  !in_range(&scaler->hsize, dflow->out_w);
+		dflow->en_split = !malidp_in_range(&scaler->hsize, dflow->in_w) ||
+				  !malidp_in_range(&scaler->hsize, dflow->out_w);
 }
 
 static bool merger_is_available(struct komeda_pipeline *pipe,
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 655938df4531..f11da95566da 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -657,12 +657,6 @@ struct block_header {
 	u32 data[];
 };
 
-/* this should be a general kernel helper */
-static int in_range(u32 addr, u32 start, u32 size)
-{
-	return addr >= start && addr < start + size;
-}
-
 static bool fw_block_mem(struct a6xx_gmu_bo *bo, const struct block_header *blk)
 {
 	if (!in_range(blk->addr, bo->iova, bo->size))
diff --git a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
index 8a167eea288c..10790a370f22 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c
@@ -2131,7 +2131,7 @@ static const struct ethtool_ops cxgb_ethtool_ops = {
 	.set_link_ksettings = set_link_ksettings,
 };
 
-static int in_range(int val, int lo, int hi)
+static int cxgb_in_range(int val, int lo, int hi)
 {
 	return val < 0 || (val <= hi && val >= lo);
 }
@@ -2162,19 +2162,19 @@ static int cxgb_extension_ioctl(struct net_device *dev, void __user *useraddr)
 			return -EINVAL;
 		if (t.qset_idx >= SGE_QSETS)
 			return -EINVAL;
-		if (!in_range(t.intr_lat, 0, M_NEWTIMER) ||
-		    !in_range(t.cong_thres, 0, 255) ||
-		    !in_range(t.txq_size[0], MIN_TXQ_ENTRIES,
+		if (!cxgb_in_range(t.intr_lat, 0, M_NEWTIMER) ||
+		    !cxgb_in_range(t.cong_thres, 0, 255) ||
+		    !cxgb_in_range(t.txq_size[0], MIN_TXQ_ENTRIES,
 			      MAX_TXQ_ENTRIES) ||
-		    !in_range(t.txq_size[1], MIN_TXQ_ENTRIES,
+		    !cxgb_in_range(t.txq_size[1], MIN_TXQ_ENTRIES,
 			      MAX_TXQ_ENTRIES) ||
-		    !in_range(t.txq_size[2], MIN_CTRL_TXQ_ENTRIES,
+		    !cxgb_in_range(t.txq_size[2], MIN_CTRL_TXQ_ENTRIES,
 			      MAX_CTRL_TXQ_ENTRIES) ||
-		    !in_range(t.fl_size[0], MIN_FL_ENTRIES,
+		    !cxgb_in_range(t.fl_size[0], MIN_FL_ENTRIES,
 			      MAX_RX_BUFFERS) ||
-		    !in_range(t.fl_size[1], MIN_FL_ENTRIES,
+		    !cxgb_in_range(t.fl_size[1], MIN_FL_ENTRIES,
 			      MAX_RX_JUMBO_BUFFERS) ||
-		    !in_range(t.rspq_size, MIN_RSPQ_ENTRIES,
+		    !cxgb_in_range(t.rspq_size, MIN_RSPQ_ENTRIES,
 			      MAX_RSPQ_ENTRIES))
 			return -EINVAL;
 
diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h
index 6461ebc3a1c1..40ad75511435 100644
--- a/fs/btrfs/misc.h
+++ b/fs/btrfs/misc.h
@@ -8,8 +8,6 @@
 #include <asm/div64.h>
 #include <linux/rbtree.h>
 
-#define in_range(b, first, len) ((b) >= (first) && (b) < (first) + (len))
-
 static inline void cond_wake_up(struct wait_queue_head *wq)
 {
 	/*
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 9bf086821eb3..1d9380c5523b 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -36,8 +36,6 @@
  */
 
 
-#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
-
 struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
 					     unsigned int block_group,
 					     struct buffer_head ** bh)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1dc1292d8977..4adaf97d7435 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3659,8 +3659,6 @@ static inline void set_bitmap_uptodate(struct buffer_head *bh)
 	set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
 }
 
-#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
-
 /* For ioend & aio unwritten conversion wait queues */
 #define EXT4_WQ_HASH_SZ		37
 #define ext4_ioend_wq(v)   (&ext4__ioend_wq[((unsigned long)(v)) %\
diff --git a/fs/ufs/util.h b/fs/ufs/util.h
index 4931bec1a01c..89247193d96d 100644
--- a/fs/ufs/util.h
+++ b/fs/ufs/util.h
@@ -11,12 +11,6 @@
 #include <linux/fs.h>
 #include "swab.h"
 
-
-/*
- * some useful macros
- */
-#define in_range(b,first,len)	((b)>=(first)&&(b)<(first)+(len))
-
 /*
  * functions used for retyping
  */
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index abdeae409dad..7affadcb2a29 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -3,6 +3,7 @@
 #define _LINUX_MINMAX_H
 
 #include <linux/const.h>
+#include <linux/types.h>
 
 /*
  * min()/max()/clamp() macros must accomplish three things:
@@ -175,6 +176,32 @@
  */
 #define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
 
+static inline bool in_range64(u64 val, u64 start, u64 len)
+{
+	return (val - start) < len;
+}
+
+static inline bool in_range32(u32 val, u32 start, u32 len)
+{
+	return (val - start) < len;
+}
+
+/**
+ * in_range - Determine if a value lies within a range.
+ * @val: Value to test.
+ * @start: First value in range.
+ * @len: Number of values in range.
+ *
+ * This is more efficient than "if (start <= val && val < (start + len))".
+ * It also gives a different answer if @start + @len overflows the size of
+ * the type by a sufficient amount to encompass @val.  Decide for yourself
+ * which behaviour you want, or prove that start + len never overflow.
+ * Do not blindly replace one form with the other.
+ */
+#define in_range(val, start, len)					\
+	((sizeof(start) | sizeof(len) | sizeof(val)) <= sizeof(u32) ?	\
+		in_range32(val, start, len) : in_range64(val, start, len))
+
 /**
  * swap - swap values of @a and @b
  * @a: first value
diff --git a/lib/logic_pio.c b/lib/logic_pio.c
index 07b4b9a1f54b..2ea564a40064 100644
--- a/lib/logic_pio.c
+++ b/lib/logic_pio.c
@@ -20,9 +20,6 @@
 static LIST_HEAD(io_range_list);
 static DEFINE_MUTEX(io_range_mutex);
 
-/* Consider a kernel general helper for this */
-#define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
-
 /**
  * logic_pio_register_range - register logical PIO range for a host
  * @new_range: pointer to the IO range to be registered.
diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index b7c3c902290f..96b61f0658c8 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -262,7 +262,7 @@ static bool l4proto_in_range(const struct nf_conntrack_tuple *tuple,
 /* If we source map this tuple so reply looks like reply_tuple, will
  * that meet the constraints of range.
  */
-static int in_range(const struct nf_conntrack_tuple *tuple,
+static int nf_in_range(const struct nf_conntrack_tuple *tuple,
 		    const struct nf_nat_range2 *range)
 {
 	/* If we are supposed to map IPs, then we must be in the
@@ -311,7 +311,7 @@ find_appropriate_src(struct net *net,
 				       &ct->tuplehash[IP_CT_DIR_REPLY].tuple);
 			result->dst = tuple->dst;
 
-			if (in_range(result, range))
+			if (nf_in_range(result, range))
 				return 1;
 		}
 	}
@@ -543,7 +543,7 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple,
 	if (maniptype == NF_NAT_MANIP_SRC &&
 	    !(range->flags & NF_NAT_RANGE_PROTO_RANDOM_ALL)) {
 		/* try the original tuple first */
-		if (in_range(orig_tuple, range)) {
+		if (nf_in_range(orig_tuple, range)) {
 			if (!nf_nat_used_tuple(orig_tuple, ct)) {
 				*tuple = *orig_tuple;
 				return;
diff --git a/net/tipc/core.h b/net/tipc/core.h
index 73a26b0b9ca1..7c86fa4bb967 100644
--- a/net/tipc/core.h
+++ b/net/tipc/core.h
@@ -199,7 +199,7 @@ static inline int less(u16 left, u16 right)
 	return less_eq(left, right) && (mod(right) != mod(left));
 }
 
-static inline int in_range(u16 val, u16 min, u16 max)
+static inline int tipc_in_range(u16 val, u16 min, u16 max)
 {
 	return !less(val, min) && !more(val, max);
 }
diff --git a/net/tipc/link.c b/net/tipc/link.c
index 336d1bb2cf6a..ca96bdb77190 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1588,7 +1588,7 @@ static int tipc_link_advance_transmq(struct tipc_link *l, struct tipc_link *r,
 					  last_ga->bgack_cnt);
 			}
 			/* Check against the last Gap ACK block */
-			if (in_range(seqno, start, end))
+			if (tipc_in_range(seqno, start, end))
 				continue;
 			/* Update/release the packet peer is acking */
 			bc_has_acked = true;
@@ -2216,12 +2216,12 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 		strncpy(if_name, data, TIPC_MAX_IF_NAME);
 
 		/* Update own tolerance if peer indicates a non-zero value */
-		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
+		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
 			l->tolerance = peers_tol;
 			l->bc_rcvlink->tolerance = peers_tol;
 		}
 		/* Update own priority if peer's priority is higher */
-		if (in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
+		if (tipc_in_range(peers_prio, l->priority + 1, TIPC_MAX_LINK_PRI))
 			l->priority = peers_prio;
 
 		/* If peer is going down we want full re-establish cycle */
@@ -2264,13 +2264,13 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
 		l->rcv_nxt_state = msg_seqno(hdr) + 1;
 
 		/* Update own tolerance if peer indicates a non-zero value */
-		if (in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
+		if (tipc_in_range(peers_tol, TIPC_MIN_LINK_TOL, TIPC_MAX_LINK_TOL)) {
 			l->tolerance = peers_tol;
 			l->bc_rcvlink->tolerance = peers_tol;
 		}
 		/* Update own prio if peer indicates a different value */
 		if ((peers_prio != l->priority) &&
-		    in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
+		    tipc_in_range(peers_prio, 1, TIPC_MAX_LINK_PRI)) {
 			l->priority = peers_prio;
 			rc = tipc_link_fsm_evt(l, LINK_FAILURE_EVT);
 		}
-- 
2.47.3

[PATCH v2 06/27 5.10.y] minmax: Introduce {min,max}_array()

[Eliav Farber]

From: Herve Codina <herve.codina@bootlin.com>

[ Upstream commit c952c748c7a983a8bda9112984e6f2c1f6e441a5 ]

Introduce min_array() (resp max_array()) in order to get the
minimal (resp maximum) of values present in an array.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20230623085830.749991-8-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 64 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 7affadcb2a29..0e89c78810f6 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -151,6 +151,70 @@
  */
 #define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)
 
+/*
+ * Remove a const qualifier from integer types
+ * _Generic(foo, type-name: association, ..., default: association) performs a
+ * comparison against the foo type (not the qualified type).
+ * Do not use the const keyword in the type-name as it will not match the
+ * unqualified type of foo.
+ */
+#define __unconst_integer_type_cases(type)	\
+	unsigned type:  (unsigned type)0,	\
+	signed type:    (signed type)0
+
+#define __unconst_integer_typeof(x) typeof(			\
+	_Generic((x),						\
+		char: (char)0,					\
+		__unconst_integer_type_cases(char),		\
+		__unconst_integer_type_cases(short),		\
+		__unconst_integer_type_cases(int),		\
+		__unconst_integer_type_cases(long),		\
+		__unconst_integer_type_cases(long long),	\
+		default: (x)))
+
+/*
+ * Do not check the array parameter using __must_be_array().
+ * In the following legit use-case where the "array" passed is a simple pointer,
+ * __must_be_array() will return a failure.
+ * --- 8< ---
+ * int *buff
+ * ...
+ * min = min_array(buff, nb_items);
+ * --- 8< ---
+ *
+ * The first typeof(&(array)[0]) is needed in order to support arrays of both
+ * 'int *buff' and 'int buff[N]' types.
+ *
+ * The array can be an array of const items.
+ * typeof() keeps the const qualifier. Use __unconst_integer_typeof() in order
+ * to discard the const qualifier for the __element variable.
+ */
+#define __minmax_array(op, array, len) ({				\
+	typeof(&(array)[0]) __array = (array);				\
+	typeof(len) __len = (len);					\
+	__unconst_integer_typeof(__array[0]) __element = __array[--__len]; \
+	while (__len--)							\
+		__element = op(__element, __array[__len]);		\
+	__element; })
+
+/**
+ * min_array - return minimum of values present in an array
+ * @array: array
+ * @len: array length
+ *
+ * Note that @len must not be zero (empty array).
+ */
+#define min_array(array, len) __minmax_array(min, array, len)
+
+/**
+ * max_array - return maximum of values present in an array
+ * @array: array
+ * @len: array length
+ *
+ * Note that @len must not be zero (empty array).
+ */
+#define max_array(array, len) __minmax_array(max, array, len)
+
 /**
  * clamp_t - return a value clamped to a given range using a given type
  * @type: the type of variable to use
-- 
2.47.3

[PATCH v2 07/27 5.10.y] minmax: deduplicate __unconst_integer_typeof()

[Eliav Farber]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit 5e57418a2031cd5e1863efdf3d7447a16a368172 ]

It appears that compiler_types.h already have an implementation of the
__unconst_integer_typeof() called __unqual_scalar_typeof().  Use it
instead of the copy.

Link: https://lkml.kernel.org/r/20230911154913.4176033-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 26 +++-----------------------
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 0e89c78810f6..c813c1187510 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MINMAX_H
 #define _LINUX_MINMAX_H
 
+#include <linux/compiler_types.h>
 #include <linux/const.h>
 #include <linux/types.h>
 
@@ -151,27 +152,6 @@
  */
 #define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)
 
-/*
- * Remove a const qualifier from integer types
- * _Generic(foo, type-name: association, ..., default: association) performs a
- * comparison against the foo type (not the qualified type).
- * Do not use the const keyword in the type-name as it will not match the
- * unqualified type of foo.
- */
-#define __unconst_integer_type_cases(type)	\
-	unsigned type:  (unsigned type)0,	\
-	signed type:    (signed type)0
-
-#define __unconst_integer_typeof(x) typeof(			\
-	_Generic((x),						\
-		char: (char)0,					\
-		__unconst_integer_type_cases(char),		\
-		__unconst_integer_type_cases(short),		\
-		__unconst_integer_type_cases(int),		\
-		__unconst_integer_type_cases(long),		\
-		__unconst_integer_type_cases(long long),	\
-		default: (x)))
-
 /*
  * Do not check the array parameter using __must_be_array().
  * In the following legit use-case where the "array" passed is a simple pointer,
@@ -186,13 +166,13 @@
  * 'int *buff' and 'int buff[N]' types.
  *
  * The array can be an array of const items.
- * typeof() keeps the const qualifier. Use __unconst_integer_typeof() in order
+ * typeof() keeps the const qualifier. Use __unqual_scalar_typeof() in order
  * to discard the const qualifier for the __element variable.
  */
 #define __minmax_array(op, array, len) ({				\
 	typeof(&(array)[0]) __array = (array);				\
 	typeof(len) __len = (len);					\
-	__unconst_integer_typeof(__array[0]) __element = __array[--__len]; \
+	__unqual_scalar_typeof(__array[0]) __element = __array[--__len];\
 	while (__len--)							\
 		__element = op(__element, __array[__len]);		\
 	__element; })
-- 
2.47.3

[PATCH v2 08/27 5.10.y] minmax: fix header inclusions

[Eliav Farber]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit f6e9d38f8eb00ac8b52e6d15f6aa9bcecacb081b ]

BUILD_BUG_ON*() macros are defined in build_bug.h.  Include it.  Replace
compiler_types.h by compiler.h, which provides the former, to have a
definition of the __UNIQUE_ID().

Link: https://lkml.kernel.org/r/20230912092355.79280-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Herve Codina <herve.codina@bootlin.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index c813c1187510..2a197f54fe05 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -2,7 +2,8 @@
 #ifndef _LINUX_MINMAX_H
 #define _LINUX_MINMAX_H
 
-#include <linux/compiler_types.h>
+#include <linux/build_bug.h>
+#include <linux/compiler.h>
 #include <linux/const.h>
 #include <linux/types.h>
 
-- 
2.47.3

[PATCH v2 09/27 5.10.y] minmax: allow min()/max()/clamp() if the arguments have the same signedness.

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit d03eba99f5bf7cbc6e2fdde3b6fa36954ad58e09 ]

The type-check in min()/max() is there to stop unexpected results if a
negative value gets converted to a large unsigned value.  However it also
rejects 'unsigned int' v 'unsigned long' compares which are common and
never problematc.

Replace the 'same type' check with a 'same signedness' check.

The new test isn't itself a compile time error, so use static_assert() to
report the error and give a meaningful error message.

Due to the way builtin_choose_expr() works detecting the error in the
'non-constant' side (where static_assert() can be used) also detects
errors when the arguments are constant.

Link: https://lkml.kernel.org/r/fe7e6c542e094bfca655abcd323c1c98@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 60 ++++++++++++++++++++++--------------------
 1 file changed, 32 insertions(+), 28 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 2a197f54fe05..8718fd71a793 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -12,9 +12,8 @@
  *
  * - avoid multiple evaluations of the arguments (so side-effects like
  *   "x++" happen only once) when non-constant.
- * - perform strict type-checking (to generate warnings instead of
- *   nasty runtime surprises). See the "unnecessary" pointer comparison
- *   in __typecheck().
+ * - perform signed v unsigned type-checking (to generate compile
+ *   errors instead of nasty runtime surprises).
  * - retain result as a constant expressions when called with only
  *   constant expressions (to avoid tripping VLA warnings in stack
  *   allocation usage).
@@ -22,23 +21,30 @@
 #define __typecheck(x, y) \
 	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
 
-#define __no_side_effects(x, y) \
-		(__is_constexpr(x) && __is_constexpr(y))
+/* is_signed_type() isn't a constexpr for pointer types */
+#define __is_signed(x) 								\
+	__builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))),	\
+		is_signed_type(typeof(x)), 0)
 
-#define __safe_cmp(x, y) \
-		(__typecheck(x, y) && __no_side_effects(x, y))
+#define __types_ok(x, y) \
+	(__is_signed(x) == __is_signed(y))
 
-#define __cmp(x, y, op)	((x) op (y) ? (x) : (y))
+#define __cmp_op_min <
+#define __cmp_op_max >
 
-#define __cmp_once(x, y, unique_x, unique_y, op) ({	\
+#define __cmp(op, x, y)	((x) __cmp_op_##op (y) ? (x) : (y))
+
+#define __cmp_once(op, x, y, unique_x, unique_y) ({	\
 		typeof(x) unique_x = (x);		\
 		typeof(y) unique_y = (y);		\
-		__cmp(unique_x, unique_y, op); })
+		static_assert(__types_ok(x, y),		\
+			#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
+		__cmp(op, unique_x, unique_y); })
 
-#define __careful_cmp(x, y, op) \
-	__builtin_choose_expr(__safe_cmp(x, y), \
-		__cmp(x, y, op), \
-		__cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
+#define __careful_cmp(op, x, y)					\
+	__builtin_choose_expr(__is_constexpr((x) - (y)),	\
+		__cmp(op, x, y),				\
+		__cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
 
 #define __clamp(val, lo, hi)	\
 	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
@@ -47,17 +53,15 @@
 		typeof(val) unique_val = (val);				\
 		typeof(lo) unique_lo = (lo);				\
 		typeof(hi) unique_hi = (hi);				\
+		static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
+				(lo) <= (hi), true),					\
+			"clamp() low limit " #lo " greater than high limit " #hi);	\
+		static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
+		static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
 		__clamp(unique_val, unique_lo, unique_hi); })
 
-#define __clamp_input_check(lo, hi)					\
-        (BUILD_BUG_ON_ZERO(__builtin_choose_expr(			\
-                __is_constexpr((lo) > (hi)), (lo) > (hi), false)))
-
 #define __careful_clamp(val, lo, hi) ({					\
-	__clamp_input_check(lo, hi) +					\
-	__builtin_choose_expr(__typecheck(val, lo) && __typecheck(val, hi) && \
-			      __typecheck(hi, lo) && __is_constexpr(val) && \
-			      __is_constexpr(lo) && __is_constexpr(hi),	\
+	__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),	\
 		__clamp(val, lo, hi),					\
 		__clamp_once(val, lo, hi, __UNIQUE_ID(__val),		\
 			     __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
@@ -67,14 +71,14 @@
  * @x: first value
  * @y: second value
  */
-#define min(x, y)	__careful_cmp(x, y, <)
+#define min(x, y)	__careful_cmp(min, x, y)
 
 /**
  * max - return maximum of two values of the same or compatible types
  * @x: first value
  * @y: second value
  */
-#define max(x, y)	__careful_cmp(x, y, >)
+#define max(x, y)	__careful_cmp(max, x, y)
 
 /**
  * umin - return minimum of two non-negative values
@@ -83,7 +87,7 @@
  * @y: second value
  */
 #define umin(x, y)	\
-	__careful_cmp((x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull, <)
+	__careful_cmp(min, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
 
 /**
  * umax - return maximum of two non-negative values
@@ -91,7 +95,7 @@
  * @y: second value
  */
 #define umax(x, y)	\
-	__careful_cmp((x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull, >)
+	__careful_cmp(max, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
 
 /**
  * min3 - return minimum of three values
@@ -143,7 +147,7 @@
  * @x: first value
  * @y: second value
  */
-#define min_t(type, x, y)	__careful_cmp((type)(x), (type)(y), <)
+#define min_t(type, x, y)	__careful_cmp(min, (type)(x), (type)(y))
 
 /**
  * max_t - return maximum of two values, using the specified type
@@ -151,7 +155,7 @@
  * @x: first value
  * @y: second value
  */
-#define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)
+#define max_t(type, x, y)	__careful_cmp(max, (type)(x), (type)(y))
 
 /*
  * Do not check the array parameter using __must_be_array().
-- 
2.47.3

[PATCH v2 10/27 5.10.y] minmax: fix indentation of __cmp_once() and __clamp_once()

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit f4b84b2ff851f01d0fac619eadef47eb41648534 ]

Remove the extra indentation and align continuation markers.

Link: https://lkml.kernel.org/r/bed41317a05c498ea0209eafbcab45a5@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 8718fd71a793..c0e738eacefa 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -35,11 +35,11 @@
 #define __cmp(op, x, y)	((x) __cmp_op_##op (y) ? (x) : (y))
 
 #define __cmp_once(op, x, y, unique_x, unique_y) ({	\
-		typeof(x) unique_x = (x);		\
-		typeof(y) unique_y = (y);		\
-		static_assert(__types_ok(x, y),		\
-			#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
-		__cmp(op, unique_x, unique_y); })
+	typeof(x) unique_x = (x);			\
+	typeof(y) unique_y = (y);			\
+	static_assert(__types_ok(x, y),			\
+		#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
+	__cmp(op, unique_x, unique_y); })
 
 #define __careful_cmp(op, x, y)					\
 	__builtin_choose_expr(__is_constexpr((x) - (y)),	\
@@ -49,16 +49,16 @@
 #define __clamp(val, lo, hi)	\
 	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
 
-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({	\
-		typeof(val) unique_val = (val);				\
-		typeof(lo) unique_lo = (lo);				\
-		typeof(hi) unique_hi = (hi);				\
-		static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
-				(lo) <= (hi), true),					\
-			"clamp() low limit " #lo " greater than high limit " #hi);	\
-		static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
-		static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
-		__clamp(unique_val, unique_lo, unique_hi); })
+#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({		\
+	typeof(val) unique_val = (val);						\
+	typeof(lo) unique_lo = (lo);						\
+	typeof(hi) unique_hi = (hi);						\
+	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
+			(lo) <= (hi), true),					\
+		"clamp() low limit " #lo " greater than high limit " #hi);	\
+	static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
+	static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
+	__clamp(unique_val, unique_lo, unique_hi); })
 
 #define __careful_clamp(val, lo, hi) ({					\
 	__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),	\
-- 
2.47.3

[PATCH v2 11/27 5.10.y] minmax: allow comparisons of 'int' against 'unsigned char/short'

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit 4ead534fba42fc4fd41163297528d2aa731cd121 ]

Since 'unsigned char/short' get promoted to 'signed int' it is safe to
compare them against an 'int' value.

Link: https://lkml.kernel.org/r/8732ef5f809c47c28a7be47c938b28d4@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index c0e738eacefa..842c1db62ffe 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -26,8 +26,9 @@
 	__builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))),	\
 		is_signed_type(typeof(x)), 0)
 
-#define __types_ok(x, y) \
-	(__is_signed(x) == __is_signed(y))
+#define __types_ok(x, y) 			\
+	(__is_signed(x) == __is_signed(y) ||	\
+		__is_signed((x) + 0) == __is_signed((y) + 0))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
-- 
2.47.3

[PATCH v2 12/27 5.10.y] minmax: relax check to allow comparison between unsigned arguments and signed constants

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit 867046cc7027703f60a46339ffde91a1970f2901 ]

Allow (for example) min(unsigned_var, 20).

The opposite min(signed_var, 20u) is still errored.

Since a comparison between signed and unsigned never makes the unsigned
value negative it is only necessary to adjust the __types_ok() test.

Link: https://lkml.kernel.org/r/633b64e2f39e46bb8234809c5595b8c7@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 842c1db62ffe..2ec559284a9f 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -10,13 +10,18 @@
 /*
  * min()/max()/clamp() macros must accomplish three things:
  *
- * - avoid multiple evaluations of the arguments (so side-effects like
+ * - Avoid multiple evaluations of the arguments (so side-effects like
  *   "x++" happen only once) when non-constant.
- * - perform signed v unsigned type-checking (to generate compile
- *   errors instead of nasty runtime surprises).
- * - retain result as a constant expressions when called with only
+ * - Retain result as a constant expressions when called with only
  *   constant expressions (to avoid tripping VLA warnings in stack
  *   allocation usage).
+ * - Perform signed v unsigned type-checking (to generate compile
+ *   errors instead of nasty runtime surprises).
+ * - Unsigned char/short are always promoted to signed int and can be
+ *   compared against signed or unsigned arguments.
+ * - Unsigned arguments can be compared against non-negative signed constants.
+ * - Comparison of a signed argument against an unsigned constant fails
+ *   even if the constant is below __INT_MAX__ and could be cast to int.
  */
 #define __typecheck(x, y) \
 	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
@@ -26,9 +31,14 @@
 	__builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))),	\
 		is_signed_type(typeof(x)), 0)
 
-#define __types_ok(x, y) 			\
-	(__is_signed(x) == __is_signed(y) ||	\
-		__is_signed((x) + 0) == __is_signed((y) + 0))
+/* True for a non-negative signed int constant */
+#define __is_noneg_int(x)	\
+	(__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0)
+
+#define __types_ok(x, y) 					\
+	(__is_signed(x) == __is_signed(y) ||			\
+		__is_signed((x) + 0) == __is_signed((y) + 0) ||	\
+		__is_noneg_int(x) || __is_noneg_int(y))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
-- 
2.47.3

[PATCH v2 13/27 5.10.y] minmax: avoid overly complicated constant expressions in VM code

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 3a7e02c040b130b5545e4b115aada7bacd80a2b6 ]

The minmax infrastructure is overkill for simple constants, and can
cause huge expansions because those simple constants are then used by
other things.

For example, 'pageblock_order' is a core VM constant, but because it was
implemented using 'min_t()' and all the type-checking that involves, it
actually expanded to something like 2.5kB of preprocessor noise.

And when that simple constant was then used inside other expansions:

  #define pageblock_nr_pages      (1UL << pageblock_order)
  #define pageblock_start_pfn(pfn)  ALIGN_DOWN((pfn), pageblock_nr_pages)

and we then use that inside a 'max()' macro:

	case ISOLATE_SUCCESS:
		update_cached = false;
		last_migrated_pfn = max(cc->zone->zone_start_pfn,
			pageblock_start_pfn(cc->migrate_pfn - 1));

the end result was that one statement expanding to 253kB in size.

There are probably other cases of this, but this one case certainly
stood out.

I've added 'MIN_T()' and 'MAX_T()' macros for this kind of "core simple
constant with specific type" use.  These macros skip the type checking,
and as such need to be very sparingly used only for obvious cases that
have active issues like this.

Reported-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/all/36aa2cad-1db1-4abf-8dd2-fb20484aabc3@lucifer.local/
Cc: David Laight <David.Laight@aculab.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 2ec559284a9f..a7ef65f78933 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -270,4 +270,11 @@ static inline bool in_range32(u32 val, u32 start, u32 len)
 #define swap(a, b) \
 	do { typeof(a) __tmp = (a); (a) = (b); (b) = __tmp; } while (0)
 
+/*
+ * Use these carefully: no type checking, and uses the arguments
+ * multiple times. Use for obvious constants only.
+ */
+#define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b))
+#define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b))
+
 #endif	/* _LINUX_MINMAX_H */
-- 
2.47.3

[PATCH v2 14/27 5.10.y] minmax: add a few more MIN_T/MAX_T users

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 4477b39c32fdc03363affef4b11d48391e6dc9ff ]

Commit 3a7e02c040b1 ("minmax: avoid overly complicated constant
expressions in VM code") added the simpler MIN_T/MAX_T macros in order
to avoid some excessive expansion from the rather complicated regular
min/max macros.

The complexity of those macros stems from two issues:

 (a) trying to use them in situations that require a C constant
     expression (in static initializers and for array sizes)

 (b) the type sanity checking

and MIN_T/MAX_T avoids both of these issues.

Now, in the whole (long) discussion about all this, it was pointed out
that the whole type sanity checking is entirely unnecessary for
min_t/max_t which get a fixed type that the comparison is done in.

But that still leaves min_t/max_t unnecessarily complicated due to
worries about the C constant expression case.

However, it turns out that there really aren't very many cases that use
min_t/max_t for this, and we can just force-convert those.

This does exactly that.

Which in turn will then allow for much simpler implementations of
min_t()/max_t().  All the usual "macros in all upper case will evaluate
the arguments multiple times" rules apply.

We should do all the same things for the regular min/max() vs MIN/MAX()
cases, but that has the added complexity of various drivers defining
their own local versions of MIN/MAX, so that needs another level of
fixes first.

Link: https://lore.kernel.org/all/b47fad1d0cf8449886ad148f8c013dae@AcuMS.aculab.com/
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 arch/x86/mm/pgtable.c                             | 2 +-
 drivers/edac/sb_edac.c                            | 4 ++--
 drivers/gpu/drm/drm_color_mgmt.c                  | 2 +-
 drivers/md/dm-integrity.c                         | 2 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
 fs/erofs/zdata.h                                  | 2 +-
 net/ipv4/proc.c                                   | 2 +-
 net/ipv6/proc.c                                   | 2 +-
 8 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 204b25ee26f0..27e8e3d6be48 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -107,7 +107,7 @@ static inline void pgd_list_del(pgd_t *pgd)
 #define UNSHARED_PTRS_PER_PGD				\
 	(SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD)
 #define MAX_UNSHARED_PTRS_PER_PGD			\
-	max_t(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
+	MAX_T(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD)
 
 
 static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
diff --git a/drivers/edac/sb_edac.c b/drivers/edac/sb_edac.c
index 1522d4aa2ca6..714020e7405a 100644
--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -109,8 +109,8 @@ static const u32 knl_interleave_list[] = {
 	0x104, 0x10c, 0x114, 0x11c,   /* 20-23 */
 };
 #define MAX_INTERLEAVE							\
-	(max_t(unsigned int, ARRAY_SIZE(sbridge_interleave_list),	\
-	       max_t(unsigned int, ARRAY_SIZE(ibridge_interleave_list),	\
+	(MAX_T(unsigned int, ARRAY_SIZE(sbridge_interleave_list),	\
+	       MAX_T(unsigned int, ARRAY_SIZE(ibridge_interleave_list),	\
 		     ARRAY_SIZE(knl_interleave_list))))
 
 struct interleave_pkg {
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 138ff34b31db..4bc671484c05 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -421,7 +421,7 @@ int drm_plane_create_color_properties(struct drm_plane *plane,
 {
 	struct drm_device *dev = plane->dev;
 	struct drm_property *prop;
-	struct drm_prop_enum_list enum_list[max_t(int, DRM_COLOR_ENCODING_MAX,
+	struct drm_prop_enum_list enum_list[MAX_T(int, DRM_COLOR_ENCODING_MAX,
 						       DRM_COLOR_RANGE_MAX)];
 	int i, len;
 
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 07a7b4e51f0e..7fa3bf74747d 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -2431,7 +2431,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start,
 				    unlikely(from_replay) &&
 #endif
 				    ic->internal_hash) {
-					char test_tag[max_t(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
+					char test_tag[MAX_T(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
 
 					integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block),
 								  (char *)access_journal_data(ic, i, l), test_tag);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b8581a711514..e6fa2782d28f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2267,7 +2267,7 @@ static void stmmac_dma_interrupt(struct stmmac_priv *priv)
 	u32 channels_to_check = tx_channel_count > rx_channel_count ?
 				tx_channel_count : rx_channel_count;
 	u32 chan;
-	int status[max_t(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];
+	int status[MAX_T(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];
 
 	/* Make sure we never check beyond our status buffer. */
 	if (WARN_ON_ONCE(channels_to_check > ARRAY_SIZE(status)))
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index 68c9b29fc0ca..d10df3f6c700 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -182,7 +182,7 @@ static inline void z_erofs_onlinepage_endio(struct page *page)
 }
 
 #define Z_EROFS_VMAP_ONSTACK_PAGES	\
-	min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U)
+	MIN_T(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U)
 #define Z_EROFS_VMAP_GLOBAL_PAGES	2048
 
 #endif
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index 80d13d8f982d..94fbba052b49 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -43,7 +43,7 @@
 #include <net/sock.h>
 #include <net/raw.h>
 
-#define TCPUDP_MIB_MAX max_t(u32, UDP_MIB_MAX, TCP_MIB_MAX)
+#define TCPUDP_MIB_MAX MAX_T(u32, UDP_MIB_MAX, TCP_MIB_MAX)
 
 /*
  *	Report socket allocation statistics [mea@utu.fi]
diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
index bbff3e02e302..929981a8fe98 100644
--- a/net/ipv6/proc.c
+++ b/net/ipv6/proc.c
@@ -27,7 +27,7 @@
 #include <net/ipv6.h>
 
 #define MAX4(a, b, c, d) \
-	max_t(u32, max_t(u32, a, b), max_t(u32, c, d))
+	MAX_T(u32, MAX_T(u32, a, b), MAX_T(u32, c, d))
 #define SNMP_MIB_MAX MAX4(UDP_MIB_MAX, TCP_MIB_MAX, \
 			IPSTATS_MIB_MAX, ICMP_MIB_MAX)
 
-- 
2.47.3

[PATCH v2 15/27 5.10.y] minmax: simplify and clarify min_t()/max_t() implementation

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 017fa3e89187848fd056af757769c9e66ac3e93d ]

This simplifies the min_t() and max_t() macros by no longer making them
work in the context of a C constant expression.

That means that you can no longer use them for static initializers or
for array sizes in type definitions, but there were only a couple of
such uses, and all of them were converted (famous last words) to use
MIN_T/MAX_T instead.

Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index a7ef65f78933..9c2848abc804 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -45,17 +45,20 @@
 
 #define __cmp(op, x, y)	((x) __cmp_op_##op (y) ? (x) : (y))
 
-#define __cmp_once(op, x, y, unique_x, unique_y) ({	\
-	typeof(x) unique_x = (x);			\
-	typeof(y) unique_y = (y);			\
+#define __cmp_once_unique(op, type, x, y, ux, uy) \
+	({ type ux = (x); type uy = (y); __cmp(op, ux, uy); })
+
+#define __cmp_once(op, type, x, y) \
+	__cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
+
+#define __careful_cmp_once(op, x, y) ({			\
 	static_assert(__types_ok(x, y),			\
 		#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
-	__cmp(op, unique_x, unique_y); })
+	__cmp_once(op, __auto_type, x, y); })
 
 #define __careful_cmp(op, x, y)					\
 	__builtin_choose_expr(__is_constexpr((x) - (y)),	\
-		__cmp(op, x, y),				\
-		__cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
+		__cmp(op, x, y), __careful_cmp_once(op, x, y))
 
 #define __clamp(val, lo, hi)	\
 	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
@@ -158,7 +161,7 @@
  * @x: first value
  * @y: second value
  */
-#define min_t(type, x, y)	__careful_cmp(min, (type)(x), (type)(y))
+#define min_t(type, x, y) __cmp_once(min, type, x, y)
 
 /**
  * max_t - return maximum of two values, using the specified type
@@ -166,7 +169,7 @@
  * @x: first value
  * @y: second value
  */
-#define max_t(type, x, y)	__careful_cmp(max, (type)(x), (type)(y))
+#define max_t(type, x, y) __cmp_once(max, type, x, y)
 
 /*
  * Do not check the array parameter using __must_be_array().
-- 
2.47.3

[PATCH v2 16/27 5.10.y] minmax: make generic MIN() and MAX() macros available everywhere

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 1a251f52cfdc417c84411a056bc142cbd77baef4 ]

This just standardizes the use of MIN() and MAX() macros, with the very
traditional semantics.  The goal is to use these for C constant
expressions and for top-level / static initializers, and so be able to
simplify the min()/max() macros.

These macro names were used by various kernel code - they are very
traditional, after all - and all such users have been fixed up, with a
few different approaches:

 - trivial duplicated macro definitions have been removed

   Note that 'trivial' here means that it's obviously kernel code that
   already included all the major kernel headers, and thus gets the new
   generic MIN/MAX macros automatically.

 - non-trivial duplicated macro definitions are guarded with #ifndef

   This is the "yes, they define their own versions, but no, the include
   situation is not entirely obvious, and maybe they don't get the
   generic version automatically" case.

 - strange use case #1

   A couple of drivers decided that the way they want to describe their
   versioning is with

	#define MAJ 1
	#define MIN 2
	#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)

   which adds zero value and I just did my Alexander the Great
   impersonation, and rewrote that pointless Gordian knot as

	#define DRV_VERSION "1.2"

   instead.

 - strange use case #2

   A couple of drivers thought that it's a good idea to have a random
   'MIN' or 'MAX' define for a value or index into a table, rather than
   the traditional macro that takes arguments.

   These values were re-written as C enum's instead. The new
   function-line macros only expand when followed by an open
   parenthesis, and thus don't clash with enum use.

Happily, there weren't really all that many of these cases, and a lot of
users already had the pattern of using '#ifndef' guarding (or in one
case just using '#undef MIN') before defining their own private version
that does the same thing. I left such cases alone.

Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 arch/um/drivers/mconsole_user.c               |  2 ++
 drivers/edac/skx_common.h                     |  1 -
 .../drm/amd/display/modules/hdcp/hdcp_ddc.c   |  2 ++
 .../drm/amd/pm/powerplay/hwmgr/ppevvmath.h    | 14 +++++++----
 drivers/gpu/drm/radeon/evergreen_cs.c         |  2 ++
 drivers/hwmon/adt7475.c                       | 24 +++++++++----------
 drivers/media/dvb-frontends/stv0367_priv.h    |  3 +++
 drivers/net/fjes/fjes_main.c                  |  4 +---
 drivers/nfc/pn544/i2c.c                       |  2 --
 drivers/platform/x86/sony-laptop.c            |  1 -
 drivers/scsi/isci/init.c                      |  6 +----
 .../pci/hive_isp_css_include/math_support.h   |  5 ----
 include/linux/minmax.h                        |  2 ++
 kernel/trace/preemptirq_delay_test.c          |  2 --
 lib/btree.c                                   |  1 -
 lib/decompress_unlzma.c                       |  2 ++
 lib/zstd/zstd_internal.h                      |  2 --
 mm/zsmalloc.c                                 |  1 -
 18 files changed, 37 insertions(+), 39 deletions(-)

diff --git a/arch/um/drivers/mconsole_user.c b/arch/um/drivers/mconsole_user.c
index e24298a734be..a04cd13c6315 100644
--- a/arch/um/drivers/mconsole_user.c
+++ b/arch/um/drivers/mconsole_user.c
@@ -71,7 +71,9 @@ static struct mconsole_command *mconsole_parse(struct mc_request *req)
 	return NULL;
 }
 
+#ifndef MIN
 #define MIN(a,b) ((a)<(b) ? (a):(b))
+#endif
 
 #define STRINGX(x) #x
 #define STRING(x) STRINGX(x)
diff --git a/drivers/edac/skx_common.h b/drivers/edac/skx_common.h
index b93c33ac8e60..5adba76c3f4d 100644
--- a/drivers/edac/skx_common.h
+++ b/drivers/edac/skx_common.h
@@ -36,7 +36,6 @@
 #define I10NM_NUM_CHANNELS	2
 #define I10NM_NUM_DIMMS		2
 
-#define MAX(a, b)	((a) > (b) ? (a) : (b))
 #define NUM_IMC		MAX(SKX_NUM_IMC, I10NM_NUM_IMC)
 #define NUM_CHANNELS	MAX(SKX_NUM_CHANNELS, I10NM_NUM_CHANNELS)
 #define NUM_DIMMS	MAX(SKX_NUM_DIMMS, I10NM_NUM_DIMMS)
diff --git a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c
index 1b2df97226a3..40286e8dd4e1 100644
--- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c
+++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_ddc.c
@@ -25,7 +25,9 @@
 
 #include "hdcp.h"
 
+#ifndef MIN
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
+#endif
 #define HDCP_I2C_ADDR 0x3a	/* 0x74 >> 1*/
 #define KSV_READ_SIZE 0xf	/* 0x6803b - 0x6802c */
 #define HDCP_MAX_AUX_TRANSACTION_SIZE 16
diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h
index 8f50a038396c..96b03a342f38 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppevvmath.h
@@ -22,12 +22,18 @@
  */
 #include <asm/div64.h>
 
-#define SHIFT_AMOUNT 16 /* We multiply all original integers with 2^SHIFT_AMOUNT to get the fInt representation */
+enum ppevvmath_constants {
+	/* We multiply all original integers with 2^SHIFT_AMOUNT to get the fInt representation */
+	SHIFT_AMOUNT	= 16,
 
-#define PRECISION 5 /* Change this value to change the number of decimal places in the final output - 5 is a good default */
+	/* Change this value to change the number of decimal places in the final output - 5 is a good default */
+	PRECISION	=  5,
 
-#define SHIFTED_2 (2 << SHIFT_AMOUNT)
-#define MAX (1 << (SHIFT_AMOUNT - 1)) - 1 /* 32767 - Might change in the future */
+	SHIFTED_2	= (2 << SHIFT_AMOUNT),
+
+	/* 32767 - Might change in the future */
+	MAX		= (1 << (SHIFT_AMOUNT - 1)) - 1,
+};
 
 /* -------------------------------------------------------------------------------
  * NEW TYPE - fINT
diff --git a/drivers/gpu/drm/radeon/evergreen_cs.c b/drivers/gpu/drm/radeon/evergreen_cs.c
index 468efa5ac8fc..3ce87e5f90f7 100644
--- a/drivers/gpu/drm/radeon/evergreen_cs.c
+++ b/drivers/gpu/drm/radeon/evergreen_cs.c
@@ -32,8 +32,10 @@
 #include "evergreen_reg_safe.h"
 #include "cayman_reg_safe.h"
 
+#ifndef MIN
 #define MAX(a,b)                   (((a)>(b))?(a):(b))
 #define MIN(a,b)                   (((a)<(b))?(a):(b))
+#endif
 
 #define REG_SAFE_BM_SIZE ARRAY_SIZE(evergreen_reg_safe_bm)
 
diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
index b4c0f01f52c4..1e0678eb0077 100644
--- a/drivers/hwmon/adt7475.c
+++ b/drivers/hwmon/adt7475.c
@@ -23,23 +23,23 @@
 #include <linux/util_macros.h>
 
 /* Indexes for the sysfs hooks */
-
-#define INPUT		0
-#define MIN		1
-#define MAX		2
-#define CONTROL		3
-#define OFFSET		3
-#define AUTOMIN		4
-#define THERM		5
-#define HYSTERSIS	6
-
+enum adt_sysfs_id {
+	INPUT		= 0,
+	MIN		= 1,
+	MAX		= 2,
+	CONTROL		= 3,
+	OFFSET		= 3,	// Dup
+	AUTOMIN		= 4,
+	THERM		= 5,
+	HYSTERSIS	= 6,
 /*
  * These are unique identifiers for the sysfs functions - unlike the
  * numbers above, these are not also indexes into an array
  */
+	ALARM		= 9,
+	FAULT		= 10,
+};
 
-#define ALARM		9
-#define FAULT		10
 
 /* 7475 Common Registers */
 
diff --git a/drivers/media/dvb-frontends/stv0367_priv.h b/drivers/media/dvb-frontends/stv0367_priv.h
index 617f605947b2..7f056d1cce82 100644
--- a/drivers/media/dvb-frontends/stv0367_priv.h
+++ b/drivers/media/dvb-frontends/stv0367_priv.h
@@ -25,8 +25,11 @@
 #endif
 
 /* MACRO definitions */
+#ifndef MIN
 #define MAX(X, Y) ((X) >= (Y) ? (X) : (Y))
 #define MIN(X, Y) ((X) <= (Y) ? (X) : (Y))
+#endif
+
 #define INRANGE(X, Y, Z) \
 	((((X) <= (Y)) && ((Y) <= (Z))) || \
 	(((Z) <= (Y)) && ((Y) <= (X))) ? 1 : 0)
diff --git a/drivers/net/fjes/fjes_main.c b/drivers/net/fjes/fjes_main.c
index 2a569eea4ee8..9a9ca5a8918e 100644
--- a/drivers/net/fjes/fjes_main.c
+++ b/drivers/net/fjes/fjes_main.c
@@ -14,9 +14,7 @@
 #include "fjes.h"
 #include "fjes_trace.h"
 
-#define MAJ 1
-#define MIN 2
-#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)
+#define DRV_VERSION "1.2"
 #define DRV_NAME	"fjes"
 char fjes_driver_name[] = DRV_NAME;
 char fjes_driver_version[] = DRV_VERSION;
diff --git a/drivers/nfc/pn544/i2c.c b/drivers/nfc/pn544/i2c.c
index 4ac8cb262559..b9a58a424933 100644
--- a/drivers/nfc/pn544/i2c.c
+++ b/drivers/nfc/pn544/i2c.c
@@ -126,8 +126,6 @@ struct pn544_i2c_fw_secure_blob {
 #define PN544_FW_CMD_RESULT_COMMAND_REJECTED 0xE0
 #define PN544_FW_CMD_RESULT_CHUNK_ERROR 0xE6
 
-#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
-
 #define PN544_FW_WRITE_BUFFER_MAX_LEN 0x9f7
 #define PN544_FW_I2C_MAX_PAYLOAD PN544_HCI_I2C_LLC_MAX_SIZE
 #define PN544_FW_I2C_WRITE_FRAME_HEADER_LEN 8
diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c
index f070e4eb74f4..a66a2ee3a9ed 100644
--- a/drivers/platform/x86/sony-laptop.c
+++ b/drivers/platform/x86/sony-laptop.c
@@ -757,7 +757,6 @@ static union acpi_object *__call_snc_method(acpi_handle handle, char *method,
 	return result;
 }
 
-#define MIN(a, b)	(a > b ? b : a)
 static int sony_nc_buffer_call(acpi_handle handle, char *name, u64 *value,
 		void *buffer, size_t buflen)
 {
diff --git a/drivers/scsi/isci/init.c b/drivers/scsi/isci/init.c
index 9d7cc62ace2e..8c7594720ef3 100644
--- a/drivers/scsi/isci/init.c
+++ b/drivers/scsi/isci/init.c
@@ -65,11 +65,7 @@
 #include "task.h"
 #include "probe_roms.h"
 
-#define MAJ 1
-#define MIN 2
-#define BUILD 0
-#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN) "." \
-	__stringify(BUILD)
+#define DRV_VERSION "1.2.0"
 
 MODULE_VERSION(DRV_VERSION);
 
diff --git a/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h b/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h
index a444ec14ff9d..1c17a87a8572 100644
--- a/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h
+++ b/drivers/staging/media/atomisp/pci/hive_isp_css_include/math_support.h
@@ -31,11 +31,6 @@
 /* A => B */
 #define IMPLIES(a, b)        (!(a) || (b))
 
-/* for preprocessor and array sizing use MIN and MAX
-   otherwise use min and max */
-#define MAX(a, b)            (((a) > (b)) ? (a) : (b))
-#define MIN(a, b)            (((a) < (b)) ? (a) : (b))
-
 #define ROUND_DIV(a, b)      (((b) != 0) ? ((a) + ((b) >> 1)) / (b) : 0)
 #define CEIL_DIV(a, b)       (((b) != 0) ? ((a) + (b) - 1) / (b) : 0)
 #define CEIL_MUL(a, b)       (CEIL_DIV(a, b) * (b))
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 9c2848abc804..fc384714da45 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -277,6 +277,8 @@ static inline bool in_range32(u32 val, u32 start, u32 len)
  * Use these carefully: no type checking, and uses the arguments
  * multiple times. Use for obvious constants only.
  */
+#define MIN(a,b) __cmp(min,a,b)
+#define MAX(a,b) __cmp(max,a,b)
 #define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b))
 #define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b))
 
diff --git a/kernel/trace/preemptirq_delay_test.c b/kernel/trace/preemptirq_delay_test.c
index 1a4f2f424996..91a3f4006ae6 100644
--- a/kernel/trace/preemptirq_delay_test.c
+++ b/kernel/trace/preemptirq_delay_test.c
@@ -31,8 +31,6 @@ MODULE_PARM_DESC(burst_size, "The size of a burst (default 1)");
 
 static struct completion done;
 
-#define MIN(x, y) ((x) < (y) ? (x) : (y))
-
 static void busy_wait(ulong time)
 {
 	u64 start, end;
diff --git a/lib/btree.c b/lib/btree.c
index b4cf08a5c267..b12f99d4c45c 100644
--- a/lib/btree.c
+++ b/lib/btree.c
@@ -43,7 +43,6 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 
-#define MAX(a, b) ((a) > (b) ? (a) : (b))
 #define NODESIZE MAX(L1_CACHE_BYTES, 128)
 
 struct btree_geo {
diff --git a/lib/decompress_unlzma.c b/lib/decompress_unlzma.c
index 1cf409ef8d04..5b9c7a1bfaf4 100644
--- a/lib/decompress_unlzma.c
+++ b/lib/decompress_unlzma.c
@@ -37,7 +37,9 @@
 
 #include <linux/decompress/mm.h>
 
+#ifndef MIN
 #define	MIN(a, b) (((a) < (b)) ? (a) : (b))
+#endif
 
 static long long INIT read_int(unsigned char *ptr, int size)
 {
diff --git a/lib/zstd/zstd_internal.h b/lib/zstd/zstd_internal.h
index dac753397f86..927ed4e8c11c 100644
--- a/lib/zstd/zstd_internal.h
+++ b/lib/zstd/zstd_internal.h
@@ -36,8 +36,6 @@
 /*-*************************************
 *  shared macros
 ***************************************/
-#define MIN(a, b) ((a) < (b) ? (a) : (b))
-#define MAX(a, b) ((a) > (b) ? (a) : (b))
 #define CHECK_F(f)                       \
 	{                                \
 		size_t const errcod = f; \
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index f5f80981ac98..bd66c28afb5c 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -126,7 +126,6 @@
 #define ISOLATED_BITS	3
 #define MAGIC_VAL_BITS	8
 
-#define MAX(a, b) ((a) >= (b) ? (a) : (b))
 /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */
 #define ZS_MIN_ALLOC_SIZE \
 	MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS))
-- 
2.47.3

[PATCH v2 17/27 5.10.y] minmax: don't use max() in situations that want a C constant expression

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit cb04e8b1d2f24c4c2c92f7b7529031fc35a16fed ]

We only had a couple of array[] declarations, and changing them to just
use 'MAX()' instead of 'max()' fixes the issue.

This will allow us to simplify our min/max macros enormously, since they
can now unconditionally use temporary variables to avoid using the
argument values multiple times.

Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 drivers/input/touchscreen/cyttsp4_core.c | 2 +-
 drivers/md/dm-integrity.c                | 4 ++--
 fs/btrfs/tree-checker.c                  | 2 +-
 lib/vsprintf.c                           | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/cyttsp4_core.c b/drivers/input/touchscreen/cyttsp4_core.c
index 02a73d9a4def..c10140c9aafa 100644
--- a/drivers/input/touchscreen/cyttsp4_core.c
+++ b/drivers/input/touchscreen/cyttsp4_core.c
@@ -857,7 +857,7 @@ static void cyttsp4_get_mt_touches(struct cyttsp4_mt_data *md, int num_cur_tch)
 	struct cyttsp4_touch tch;
 	int sig;
 	int i, j, t = 0;
-	int ids[max(CY_TMA1036_MAX_TCH, CY_TMA4XX_MAX_TCH)];
+	int ids[MAX(CY_TMA1036_MAX_TCH, CY_TMA4XX_MAX_TCH)];
 
 	memset(ids, 0, si->si_ofs.tch_abs[CY_TCH_T].max * sizeof(int));
 	for (i = 0; i < num_cur_tch; i++) {
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 7fa3bf74747d..917ba18be77f 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1600,7 +1600,7 @@ static void integrity_metadata(struct work_struct *w)
 		struct bio *bio = dm_bio_from_per_bio_data(dio, sizeof(struct dm_integrity_io));
 		char *checksums;
 		unsigned extra_space = unlikely(digest_size > ic->tag_size) ? digest_size - ic->tag_size : 0;
-		char checksums_onstack[max((size_t)HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
+		char checksums_onstack[MAX(HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
 		sector_t sector;
 		unsigned sectors_to_process;
 
@@ -1882,7 +1882,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio,
 				} while (++s < ic->sectors_per_block);
 #ifdef INTERNAL_VERIFY
 				if (ic->internal_hash) {
-					char checksums_onstack[max((size_t)HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
+					char checksums_onstack[MAX(HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
 
 					integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack);
 					if (unlikely(memcmp(checksums_onstack, journal_entry_tag(ic, je), ic->tag_size))) {
diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index c28bb37688c6..fd4768c5e439 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -587,7 +587,7 @@ static int check_dir_item(struct extent_buffer *leaf,
 		 */
 		if (key->type == BTRFS_DIR_ITEM_KEY ||
 		    key->type == BTRFS_XATTR_ITEM_KEY) {
-			char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];
+			char namebuf[MAX(BTRFS_NAME_LEN, XATTR_NAME_MAX)];
 
 			read_extent_buffer(leaf, namebuf,
 					(unsigned long)(di + 1), name_len);
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index b08b8ee1bbc0..90372391ce90 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1078,7 +1078,7 @@ char *resource_string(char *buf, char *end, struct resource *res,
 #define FLAG_BUF_SIZE		(2 * sizeof(res->flags))
 #define DECODED_BUF_SIZE	sizeof("[mem - 64bit pref window disabled]")
 #define RAW_BUF_SIZE		sizeof("[mem - flags 0x]")
-	char sym[max(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
+	char sym[MAX(2*RSRC_BUF_SIZE + DECODED_BUF_SIZE,
 		     2*RSRC_BUF_SIZE + FLAG_BUF_SIZE + RAW_BUF_SIZE)];
 
 	char *p = sym, *pend = sym + sizeof(sym);
-- 
2.47.3

[PATCH v2 18/27 5.10.y] minmax: simplify min()/max()/clamp() implementation

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit dc1c8034e31b14a2e5e212104ec508aec44ce1b9 ]

Now that we no longer have any C constant expression contexts (ie array
size declarations or static initializers) that use min() or max(), we
can simpify the implementation by not having to worry about the result
staying as a C constant expression.

So now we can unconditionally just use temporary variables of the right
type, and get rid of the excessive expansion that used to come from the
use of

   __builtin_choose_expr(__is_constexpr(...), ..

to pick the specialized code for constant expressions.

Another expansion simplification is to pass the temporary variables (in
addition to the original expression) to our __types_ok() macro.  That
may superficially look like it complicates the macro, but when we only
want the type of the expression, expanding the temporary variable names
is much simpler and smaller than expanding the potentially complicated
original expression.

As a result, on my machine, doing a

  $ time make drivers/staging/media/atomisp/pci/isp/kernels/ynr/ynr_1.0/ia_css_ynr.host.i

goes from

	real	0m16.621s
	user	0m15.360s
	sys	0m1.221s

to

	real	0m2.532s
	user	0m2.091s
	sys	0m0.452s

because the token expansion goes down dramatically.

In particular, the longest line expansion (which was line 71 of that
'ia_css_ynr.host.c' file) shrinks from 23,338kB (yes, 23MB for one
single line) to "just" 1,444kB (now "only" 1.4MB).

And yes, that line is still the line from hell, because it's doing
multiple levels of "min()/max()" expansion thanks to some of them being
hidden inside the uDIGIT_FITTING() macro.

Lorenzo has a nice cleanup patch that makes that driver use inline
functions instead of macros for sDIGIT_FITTING() and uDIGIT_FITTING(),
which will fix that line once and for all, but the 16-fold reduction in
this case does show why we need to simplify these helpers.

Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 43 ++++++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index fc384714da45..e3e4353df983 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -35,10 +35,10 @@
 #define __is_noneg_int(x)	\
 	(__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0)
 
-#define __types_ok(x, y) 					\
-	(__is_signed(x) == __is_signed(y) ||			\
-		__is_signed((x) + 0) == __is_signed((y) + 0) ||	\
-		__is_noneg_int(x) || __is_noneg_int(y))
+#define __types_ok(x, y, ux, uy) 				\
+	(__is_signed(ux) == __is_signed(uy) ||			\
+	 __is_signed((ux) + 0) == __is_signed((uy) + 0) ||	\
+	 __is_noneg_int(x) || __is_noneg_int(y))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
@@ -51,34 +51,31 @@
 #define __cmp_once(op, type, x, y) \
 	__cmp_once_unique(op, type, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
 
-#define __careful_cmp_once(op, x, y) ({			\
-	static_assert(__types_ok(x, y),			\
+#define __careful_cmp_once(op, x, y, ux, uy) ({		\
+	__auto_type ux = (x); __auto_type uy = (y);	\
+	static_assert(__types_ok(x, y, ux, uy),		\
 		#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
-	__cmp_once(op, __auto_type, x, y); })
+	__cmp(op, ux, uy); })
 
-#define __careful_cmp(op, x, y)					\
-	__builtin_choose_expr(__is_constexpr((x) - (y)),	\
-		__cmp(op, x, y), __careful_cmp_once(op, x, y))
+#define __careful_cmp(op, x, y) \
+	__careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
 
 #define __clamp(val, lo, hi)	\
 	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
 
-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({		\
-	typeof(val) unique_val = (val);						\
-	typeof(lo) unique_lo = (lo);						\
-	typeof(hi) unique_hi = (hi);						\
+#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({				\
+	__auto_type uval = (val);						\
+	__auto_type ulo = (lo);							\
+	__auto_type uhi = (hi);							\
 	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
 			(lo) <= (hi), true),					\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
-	static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error");	\
-	static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error");	\
-	__clamp(unique_val, unique_lo, unique_hi); })
-
-#define __careful_clamp(val, lo, hi) ({					\
-	__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)),	\
-		__clamp(val, lo, hi),					\
-		__clamp_once(val, lo, hi, __UNIQUE_ID(__val),		\
-			     __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
+	static_assert(__types_ok(uval, lo, uval, ulo), "clamp() 'lo' signedness error");	\
+	static_assert(__types_ok(uval, hi, uval, uhi), "clamp() 'hi' signedness error");	\
+	__clamp(uval, ulo, uhi); })
+
+#define __careful_clamp(val, lo, hi) \
+	__clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
 
 /**
  * min - return minimum of two values of the same or compatible types
-- 
2.47.3

[PATCH v2 19/27 5.10.y] minmax: improve macro expansion and type checking

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 22f5468731491e53356ba7c028f0fdea20b18e2c ]

This clarifies the rules for min()/max()/clamp() type checking and makes
them a much more efficient macro expansion.

In particular, we now look at the type and range of the inputs to see
whether they work together, generating a mask of acceptable comparisons,
and then just verifying that the inputs have a shared case:

 - an expression with a signed type can be used for
    (1) signed comparisons
    (2) unsigned comparisons if it is statically known to have a
        non-negative value

 - an expression with an unsigned type can be used for
    (3) unsigned comparison
    (4) signed comparisons if the type is smaller than 'int' and thus
        the C integer promotion rules will make it signed anyway

Here rule (1) and (3) are obvious, and rule (2) is important in order to
allow obvious trivial constants to be used together with unsigned
values.

Rule (4) is not necessarily a good idea, but matches what we used to do,
and we have extant cases of this situation in the kernel.  Notably with
bcachefs having an expression like

	min(bch2_bucket_sectors_dirty(a), ca->mi.bucket_size)

where bch2_bucket_sectors_dirty() returns an 's64', and
'ca->mi.bucket_size' is of type 'u16'.

Technically that bcachefs comparison is clearly sensible on a C type
level, because the 'u16' will go through the normal C integer promotion,
and become 'int', and then we're comparing two signed values and
everything looks sane.

However, it's not entirely clear that a 'min(s64,u16)' operation makes a
lot of conceptual sense, and it's possible that we will remove rule (4).
After all, the _reason_ we have these complicated type checks is exactly
that the C type promotion rules are not very intuitive.

But at least for now the rule is in place for backwards compatibility.

Also note that rule (2) existed before, but is hugely relaxed by this
commit.  It used to be true only for the simplest compile-time
non-negative integer constants.  The new macro model will allow cases
where the compiler can trivially see that an expression is non-negative
even if it isn't necessarily a constant.

For example, the amdgpu driver does

	min_t(size_t, sizeof(fru_info->serial), pia[addr] & 0x3F));

because our old 'min()' macro would see that 'pia[addr] & 0x3F' is of
type 'int' and clearly not a C constant expression, so doing a 'min()'
with a 'size_t' is a signedness violation.

Our new 'min()' macro still sees that 'pia[addr] & 0x3F' is of type
'int', but is smart enough to also see that it is clearly non-negative,
and thus would allow that case without any complaints.

Cc: Arnd Bergmann <arnd@kernel.org>
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/compiler.h |  9 +++++
 include/linux/minmax.h   | 74 ++++++++++++++++++++++++++++++++--------
 2 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 004a030d5ad2..28b21e372751 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -251,6 +251,15 @@ static inline void *offset_to_ptr(const int *off)
  */
 #define is_signed_type(type) (((type)(-1)) < (__force type)1)
 
+/*
+ * Useful shorthand for "is this condition known at compile-time?"
+ *
+ * Note that the condition may involve non-constant values,
+ * but the compiler may know enough about the details of the
+ * values to determine that the condition is statically true.
+ */
+#define statically_true(x) (__builtin_constant_p(x) && (x))
+
 /*
  * This is needed in functions which generate the stack canary, see
  * arch/x86/kernel/smpboot.c::start_secondary() for an example.
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index e3e4353df983..41da6f85a407 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -26,19 +26,63 @@
 #define __typecheck(x, y) \
 	(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
 
-/* is_signed_type() isn't a constexpr for pointer types */
-#define __is_signed(x) 								\
-	__builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))),	\
-		is_signed_type(typeof(x)), 0)
+/*
+ * __sign_use for integer expressions:
+ *   bit #0 set if ok for unsigned comparisons
+ *   bit #1 set if ok for signed comparisons
+ *
+ * In particular, statically non-negative signed integer
+ * expressions are ok for both.
+ *
+ * NOTE! Unsigned types smaller than 'int' are implicitly
+ * converted to 'int' in expressions, and are accepted for
+ * signed conversions for now. This is debatable.
+ *
+ * Note that 'x' is the original expression, and 'ux' is
+ * the unique variable that contains the value.
+ *
+ * We use 'ux' for pure type checking, and 'x' for when
+ * we need to look at the value (but without evaluating
+ * it for side effects! Careful to only ever evaluate it
+ * with sizeof() or __builtin_constant_p() etc).
+ *
+ * Pointers end up being checked by the normal C type
+ * rules at the actual comparison, and these expressions
+ * only need to be careful to not cause warnings for
+ * pointer use.
+ */
+#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux))
+#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4))
+#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \
+	__signed_type_use(x,ux):__unsigned_type_use(x,ux))
+
+/*
+ * To avoid warnings about casting pointers to integers
+ * of different sizes, we need that special sign type.
+ *
+ * On 64-bit we can just always use 'long', since any
+ * integer or pointer type can just be cast to that.
+ *
+ * This does not work for 128-bit signed integers since
+ * the cast would truncate them, but we do not use s128
+ * types in the kernel (we do use 'u128', but they will
+ * be handled by the !is_signed_type() case).
+ *
+ * NOTE! The cast is there only to avoid any warnings
+ * from when values that aren't signed integer types.
+ */
+#ifdef CONFIG_64BIT
+  #define __signed_type(ux) long
+#else
+  #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L))
+#endif
+#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0)
 
-/* True for a non-negative signed int constant */
-#define __is_noneg_int(x)	\
-	(__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0)
+#define __types_ok(x,y,ux,uy) \
+	(__sign_use(x,ux) & __sign_use(y,uy))
 
-#define __types_ok(x, y, ux, uy) 				\
-	(__is_signed(ux) == __is_signed(uy) ||			\
-	 __is_signed((ux) + 0) == __is_signed((uy) + 0) ||	\
-	 __is_noneg_int(x) || __is_noneg_int(y))
+#define __types_ok3(x,y,z,ux,uy,uz) \
+	(__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
@@ -53,8 +97,8 @@
 
 #define __careful_cmp_once(op, x, y, ux, uy) ({		\
 	__auto_type ux = (x); __auto_type uy = (y);	\
-	static_assert(__types_ok(x, y, ux, uy),		\
-		#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
+	BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy),	\
+		#op"("#x", "#y") signedness error");	\
 	__cmp(op, ux, uy); })
 
 #define __careful_cmp(op, x, y) \
@@ -70,8 +114,8 @@
 	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
 			(lo) <= (hi), true),					\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
-	static_assert(__types_ok(uval, lo, uval, ulo), "clamp() 'lo' signedness error");	\
-	static_assert(__types_ok(uval, hi, uval, uhi), "clamp() 'hi' signedness error");	\
+	BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi),			\
+		"clamp("#val", "#lo", "#hi") signedness error");		\
 	__clamp(uval, ulo, uhi); })
 
 #define __careful_clamp(val, lo, hi) \
-- 
2.47.3

[PATCH v2 20/27 5.10.y] minmax: fix up min3() and max3() too

[Eliav Farber]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit 21b136cc63d2a9ddd60d4699552b69c214b32964 ]

David Laight pointed out that we should deal with the min3() and max3()
mess too, which still does excessive expansion.

And our current macros are actually rather broken.

In particular, the macros did this:

  #define min3(x, y, z) min((typeof(x))min(x, y), z)
  #define max3(x, y, z) max((typeof(x))max(x, y), z)

and that not only is a nested expansion of possibly very complex
arguments with all that involves, the typing with that "typeof()" cast
is completely wrong.

For example, imagine what happens in max3() if 'x' happens to be a
'unsigned char', but 'y' and 'z' are 'unsigned long'.  The types are
compatible, and there's no warning - but the result is just random
garbage.

No, I don't think we've ever hit that issue in practice, but since we
now have sane infrastructure for doing this right, let's just use it.
It fixes any excessive expansion, and also avoids these kinds of broken
type issues.

Requested-by: David Laight <David.Laight@aculab.com>
Acked-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 41da6f85a407..98008dd92153 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -152,13 +152,20 @@
 #define umax(x, y)	\
 	__careful_cmp(max, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
 
+#define __careful_op3(op, x, y, z, ux, uy, uz) ({			\
+	__auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\
+	BUILD_BUG_ON_MSG(!__types_ok3(x,y,z,ux,uy,uz),			\
+		#op"3("#x", "#y", "#z") signedness error");		\
+	__cmp(op, ux, __cmp(op, uy, uz)); })
+
 /**
  * min3 - return minimum of three values
  * @x: first value
  * @y: second value
  * @z: third value
  */
-#define min3(x, y, z) min((typeof(x))min(x, y), z)
+#define min3(x, y, z) \
+	__careful_op3(min, x, y, z, __UNIQUE_ID(x_), __UNIQUE_ID(y_), __UNIQUE_ID(z_))
 
 /**
  * max3 - return maximum of three values
@@ -166,7 +173,8 @@
  * @y: second value
  * @z: third value
  */
-#define max3(x, y, z) max((typeof(x))max(x, y), z)
+#define max3(x, y, z) \
+	__careful_op3(max, x, y, z, __UNIQUE_ID(x_), __UNIQUE_ID(y_), __UNIQUE_ID(z_))
 
 /**
  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
-- 
2.47.3

[PATCH v2 21/27 5.10.y] minmax.h: add whitespace around operators and after commas

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit 71ee9b16251ea4bf7c1fe222517c82bdb3220acc ]

Patch series "minmax.h: Cleanups and minor optimisations".

Some tidyups and minor changes to minmax.h.

This patch (of 7):

Link: https://lkml.kernel.org/r/c50365d214e04f9ba256d417c8bebbc0@AcuMS.aculab.com
Link: https://lkml.kernel.org/r/f04b2e1310244f62826267346fde0553@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 98008dd92153..51b0d988e322 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -51,10 +51,10 @@
  * only need to be careful to not cause warnings for
  * pointer use.
  */
-#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux))
-#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4))
-#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \
-	__signed_type_use(x,ux):__unsigned_type_use(x,ux))
+#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux))
+#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4))
+#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \
+	__signed_type_use(x, ux) : __unsigned_type_use(x, ux))
 
 /*
  * To avoid warnings about casting pointers to integers
@@ -74,15 +74,15 @@
 #ifdef CONFIG_64BIT
   #define __signed_type(ux) long
 #else
-  #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L))
+  #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L))
 #endif
-#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0)
+#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0)
 
-#define __types_ok(x,y,ux,uy) \
-	(__sign_use(x,ux) & __sign_use(y,uy))
+#define __types_ok(x, y, ux, uy) \
+	(__sign_use(x, ux) & __sign_use(y, uy))
 
-#define __types_ok3(x,y,z,ux,uy,uz) \
-	(__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz))
+#define __types_ok3(x, y, z, ux, uy, uz) \
+	(__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
@@ -97,7 +97,7 @@
 
 #define __careful_cmp_once(op, x, y, ux, uy) ({		\
 	__auto_type ux = (x); __auto_type uy = (y);	\
-	BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy),	\
+	BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy),	\
 		#op"("#x", "#y") signedness error");	\
 	__cmp(op, ux, uy); })
 
@@ -114,7 +114,7 @@
 	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
 			(lo) <= (hi), true),					\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
-	BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi),			\
+	BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi),		\
 		"clamp("#val", "#lo", "#hi") signedness error");		\
 	__clamp(uval, ulo, uhi); })
 
@@ -154,7 +154,7 @@
 
 #define __careful_op3(op, x, y, z, ux, uy, uz) ({			\
 	__auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\
-	BUILD_BUG_ON_MSG(!__types_ok3(x,y,z,ux,uy,uz),			\
+	BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz),		\
 		#op"3("#x", "#y", "#z") signedness error");		\
 	__cmp(op, ux, __cmp(op, uy, uz)); })
 
@@ -326,9 +326,9 @@ static inline bool in_range32(u32 val, u32 start, u32 len)
  * Use these carefully: no type checking, and uses the arguments
  * multiple times. Use for obvious constants only.
  */
-#define MIN(a,b) __cmp(min,a,b)
-#define MAX(a,b) __cmp(max,a,b)
-#define MIN_T(type,a,b) __cmp(min,(type)(a),(type)(b))
-#define MAX_T(type,a,b) __cmp(max,(type)(a),(type)(b))
+#define MIN(a, b) __cmp(min, a, b)
+#define MAX(a, b) __cmp(max, a, b)
+#define MIN_T(type, a, b) __cmp(min, (type)(a), (type)(b))
+#define MAX_T(type, a, b) __cmp(max, (type)(a), (type)(b))
 
 #endif	/* _LINUX_MINMAX_H */
-- 
2.47.3

[PATCH v2 22/27 5.10.y] minmax.h: update some comments

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit 10666e99204818ef45c702469488353b5bb09ec7 ]

- Change three to several.
- Remove the comment about retaining constant expressions, no longer true.
- Realign to nearer 80 columns and break on major punctiation.
- Add a leading comment to the block before __signed_type() and __is_nonneg()
  Otherwise the block explaining the cast is a bit 'floating'.
  Reword the rest of that comment to improve readability.

Link: https://lkml.kernel.org/r/85b050c81c1d4076aeb91a6cded45fee@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 53 +++++++++++++++++++-----------------------
 1 file changed, 24 insertions(+), 29 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 51b0d988e322..24e4b372649a 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -8,13 +8,10 @@
 #include <linux/types.h>
 
 /*
- * min()/max()/clamp() macros must accomplish three things:
+ * min()/max()/clamp() macros must accomplish several things:
  *
  * - Avoid multiple evaluations of the arguments (so side-effects like
  *   "x++" happen only once) when non-constant.
- * - Retain result as a constant expressions when called with only
- *   constant expressions (to avoid tripping VLA warnings in stack
- *   allocation usage).
  * - Perform signed v unsigned type-checking (to generate compile
  *   errors instead of nasty runtime surprises).
  * - Unsigned char/short are always promoted to signed int and can be
@@ -31,25 +28,23 @@
  *   bit #0 set if ok for unsigned comparisons
  *   bit #1 set if ok for signed comparisons
  *
- * In particular, statically non-negative signed integer
- * expressions are ok for both.
+ * In particular, statically non-negative signed integer expressions
+ * are ok for both.
  *
- * NOTE! Unsigned types smaller than 'int' are implicitly
- * converted to 'int' in expressions, and are accepted for
- * signed conversions for now. This is debatable.
+ * NOTE! Unsigned types smaller than 'int' are implicitly converted to 'int'
+ * in expressions, and are accepted for signed conversions for now.
+ * This is debatable.
  *
- * Note that 'x' is the original expression, and 'ux' is
- * the unique variable that contains the value.
+ * Note that 'x' is the original expression, and 'ux' is the unique variable
+ * that contains the value.
  *
- * We use 'ux' for pure type checking, and 'x' for when
- * we need to look at the value (but without evaluating
- * it for side effects! Careful to only ever evaluate it
- * with sizeof() or __builtin_constant_p() etc).
+ * We use 'ux' for pure type checking, and 'x' for when we need to look at the
+ * value (but without evaluating it for side effects!
+ * Careful to only ever evaluate it with sizeof() or __builtin_constant_p() etc).
  *
- * Pointers end up being checked by the normal C type
- * rules at the actual comparison, and these expressions
- * only need to be careful to not cause warnings for
- * pointer use.
+ * Pointers end up being checked by the normal C type rules at the actual
+ * comparison, and these expressions only need to be careful to not cause
+ * warnings for pointer use.
  */
 #define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux))
 #define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4))
@@ -57,19 +52,19 @@
 	__signed_type_use(x, ux) : __unsigned_type_use(x, ux))
 
 /*
- * To avoid warnings about casting pointers to integers
- * of different sizes, we need that special sign type.
+ * Check whether a signed value is always non-negative.
  *
- * On 64-bit we can just always use 'long', since any
- * integer or pointer type can just be cast to that.
+ * A cast is needed to avoid any warnings from values that aren't signed
+ * integer types (in which case the result doesn't matter).
  *
- * This does not work for 128-bit signed integers since
- * the cast would truncate them, but we do not use s128
- * types in the kernel (we do use 'u128', but they will
- * be handled by the !is_signed_type() case).
+ * On 64-bit any integer or pointer type can safely be cast to 'long'.
+ * But on 32-bit we need to avoid warnings about casting pointers to integers
+ * of different sizes without truncating 64-bit values so 'long' or 'long long'
+ * must be used depending on the size of the value.
  *
- * NOTE! The cast is there only to avoid any warnings
- * from when values that aren't signed integer types.
+ * This does not work for 128-bit signed integers since the cast would truncate
+ * them, but we do not use s128 types in the kernel (we do use 'u128',
+ * but they are handled by the !is_signed_type() case).
  */
 #ifdef CONFIG_64BIT
   #define __signed_type(ux) long
-- 
2.47.3

[PATCH v2 23/27 5.10.y] minmax.h: reduce the #define expansion of min(), max() and clamp()

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit b280bb27a9f7c91ddab730e1ad91a9c18a051f41 ]

Since the test for signed values being non-negative only relies on
__builtion_constant_p() (not is_constexpr()) it can use the 'ux' variable
instead of the caller supplied expression.  This means that the #define
parameters are only expanded twice.  Once in the code and once quoted in
the error message.

Link: https://lkml.kernel.org/r/051afc171806425da991908ed8688a98@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 24e4b372649a..6f7ea669d305 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -46,10 +46,10 @@
  * comparison, and these expressions only need to be careful to not cause
  * warnings for pointer use.
  */
-#define __signed_type_use(x, ux) (2 + __is_nonneg(x, ux))
-#define __unsigned_type_use(x, ux) (1 + 2 * (sizeof(ux) < 4))
-#define __sign_use(x, ux) (is_signed_type(typeof(ux)) ? \
-	__signed_type_use(x, ux) : __unsigned_type_use(x, ux))
+#define __signed_type_use(ux) (2 + __is_nonneg(ux))
+#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4))
+#define __sign_use(ux) (is_signed_type(typeof(ux)) ? \
+	__signed_type_use(ux) : __unsigned_type_use(ux))
 
 /*
  * Check whether a signed value is always non-negative.
@@ -71,13 +71,13 @@
 #else
   #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L))
 #endif
-#define __is_nonneg(x, ux) statically_true((__signed_type(ux))(x) >= 0)
+#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)
 
-#define __types_ok(x, y, ux, uy) \
-	(__sign_use(x, ux) & __sign_use(y, uy))
+#define __types_ok(ux, uy) \
+	(__sign_use(ux) & __sign_use(uy))
 
-#define __types_ok3(x, y, z, ux, uy, uz) \
-	(__sign_use(x, ux) & __sign_use(y, uy) & __sign_use(z, uz))
+#define __types_ok3(ux, uy, uz) \
+	(__sign_use(ux) & __sign_use(uy) & __sign_use(uz))
 
 #define __cmp_op_min <
 #define __cmp_op_max >
@@ -92,7 +92,7 @@
 
 #define __careful_cmp_once(op, x, y, ux, uy) ({		\
 	__auto_type ux = (x); __auto_type uy = (y);	\
-	BUILD_BUG_ON_MSG(!__types_ok(x, y, ux, uy),	\
+	BUILD_BUG_ON_MSG(!__types_ok(ux, uy),		\
 		#op"("#x", "#y") signedness error");	\
 	__cmp(op, ux, uy); })
 
@@ -109,7 +109,7 @@
 	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
 			(lo) <= (hi), true),					\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
-	BUILD_BUG_ON_MSG(!__types_ok3(val, lo, hi, uval, ulo, uhi),		\
+	BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
 		"clamp("#val", "#lo", "#hi") signedness error");		\
 	__clamp(uval, ulo, uhi); })
 
@@ -149,7 +149,7 @@
 
 #define __careful_op3(op, x, y, z, ux, uy, uz) ({			\
 	__auto_type ux = (x); __auto_type uy = (y);__auto_type uz = (z);\
-	BUILD_BUG_ON_MSG(!__types_ok3(x, y, z, ux, uy, uz),		\
+	BUILD_BUG_ON_MSG(!__types_ok3(ux, uy, uz),			\
 		#op"3("#x", "#y", "#z") signedness error");		\
 	__cmp(op, ux, __cmp(op, uy, uz)); })
 
-- 
2.47.3

[PATCH v2 24/27 5.10.y] minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp()

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit a5743f32baec4728711bbc01d6ac2b33d4c67040 ]

Use BUILD_BUG_ON_MSG(statically_true(ulo > uhi), ...) for the sanity check
of the bounds in clamp().  Gives better error coverage and one less
expansion of the arguments.

Link: https://lkml.kernel.org/r/34d53778977747f19cce2abb287bb3e6@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 6f7ea669d305..91aa1b90c1bb 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -106,8 +106,7 @@
 	__auto_type uval = (val);						\
 	__auto_type ulo = (lo);							\
 	__auto_type uhi = (hi);							\
-	static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), 	\
-			(lo) <= (hi), true),					\
+	BUILD_BUG_ON_MSG(statically_true(ulo > uhi),				\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
 	BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
 		"clamp("#val", "#lo", "#hi") signedness error");		\
-- 
2.47.3

[PATCH v2 25/27 5.10.y] minmax.h: move all the clamp() definitions after the min/max() ones

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit c3939872ee4a6b8bdcd0e813c66823b31e6e26f7 ]

At some point the definitions for clamp() got added in the middle of the
ones for min() and max().  Re-order the definitions so they are more
sensibly grouped.

Link: https://lkml.kernel.org/r/8bb285818e4846469121c8abc3dfb6e2@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 109 +++++++++++++++++++----------------------
 1 file changed, 51 insertions(+), 58 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 91aa1b90c1bb..75fb7a6ad4c6 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -99,22 +99,6 @@
 #define __careful_cmp(op, x, y) \
 	__careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
 
-#define __clamp(val, lo, hi)	\
-	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
-
-#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({				\
-	__auto_type uval = (val);						\
-	__auto_type ulo = (lo);							\
-	__auto_type uhi = (hi);							\
-	BUILD_BUG_ON_MSG(statically_true(ulo > uhi),				\
-		"clamp() low limit " #lo " greater than high limit " #hi);	\
-	BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
-		"clamp("#val", "#lo", "#hi") signedness error");		\
-	__clamp(uval, ulo, uhi); })
-
-#define __careful_clamp(val, lo, hi) \
-	__clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
-
 /**
  * min - return minimum of two values of the same or compatible types
  * @x: first value
@@ -170,6 +154,22 @@
 #define max3(x, y, z) \
 	__careful_op3(max, x, y, z, __UNIQUE_ID(x_), __UNIQUE_ID(y_), __UNIQUE_ID(z_))
 
+/**
+ * min_t - return minimum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define min_t(type, x, y) __cmp_once(min, type, x, y)
+
+/**
+ * max_t - return maximum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define max_t(type, x, y) __cmp_once(max, type, x, y)
+
 /**
  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
  * @x: value1
@@ -180,6 +180,22 @@
 	typeof(y) __y = (y);			\
 	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
 
+#define __clamp(val, lo, hi)	\
+	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
+
+#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({				\
+	__auto_type uval = (val);						\
+	__auto_type ulo = (lo);							\
+	__auto_type uhi = (hi);							\
+	BUILD_BUG_ON_MSG(statically_true(ulo > uhi),				\
+		"clamp() low limit " #lo " greater than high limit " #hi);	\
+	BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
+		"clamp("#val", "#lo", "#hi") signedness error");		\
+	__clamp(uval, ulo, uhi); })
+
+#define __careful_clamp(val, lo, hi) \
+	__clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
+
 /**
  * clamp - return a value clamped to a given range with strict typechecking
  * @val: current value
@@ -191,28 +207,30 @@
  */
 #define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
 
-/*
- * ..and if you can't take the strict
- * types, you can specify one yourself.
- *
- * Or not use min/max/clamp at all, of course.
- */
-
 /**
- * min_t - return minimum of two values, using the specified type
- * @type: data type to use
- * @x: first value
- * @y: second value
+ * clamp_t - return a value clamped to a given range using a given type
+ * @type: the type of variable to use
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of type
+ * @type to make all the comparisons.
  */
-#define min_t(type, x, y) __cmp_once(min, type, x, y)
+#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
 
 /**
- * max_t - return maximum of two values, using the specified type
- * @type: data type to use
- * @x: first value
- * @y: second value
+ * clamp_val - return a value clamped to a given range using val's type
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of whatever
+ * type the input argument @val is.  This is useful when @val is an unsigned
+ * type and @lo and @hi are literals that will otherwise be assigned a signed
+ * integer type.
  */
-#define max_t(type, x, y) __cmp_once(max, type, x, y)
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
 
 /*
  * Do not check the array parameter using __must_be_array().
@@ -257,31 +275,6 @@
  */
 #define max_array(array, len) __minmax_array(max, array, len)
 
-/**
- * clamp_t - return a value clamped to a given range using a given type
- * @type: the type of variable to use
- * @val: current value
- * @lo: minimum allowable value
- * @hi: maximum allowable value
- *
- * This macro does no typechecking and uses temporary variables of type
- * @type to make all the comparisons.
- */
-#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
-
-/**
- * clamp_val - return a value clamped to a given range using val's type
- * @val: current value
- * @lo: minimum allowable value
- * @hi: maximum allowable value
- *
- * This macro does no typechecking and uses temporary variables of whatever
- * type the input argument @val is.  This is useful when @val is an unsigned
- * type and @lo and @hi are literals that will otherwise be assigned a signed
- * integer type.
- */
-#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
-
 static inline bool in_range64(u64 val, u64 start, u64 len)
 {
 	return (val - start) < len;
-- 
2.47.3

[PATCH v2 26/27 5.10.y] minmax.h: simplify the variants of clamp()

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit 495bba17cdf95e9703af1b8ef773c55ef0dfe703 ]

Always pass a 'type' through to __clamp_once(), pass '__auto_type' from
clamp() itself.

The expansion of __types_ok3() is reasonable so it isn't worth the added
complexity of avoiding it when a fixed type is used for all three values.

Link: https://lkml.kernel.org/r/8f69f4deac014f558bab186444bac2e8@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 75fb7a6ad4c6..2bbdd5b5e07e 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -183,29 +183,29 @@
 #define __clamp(val, lo, hi)	\
 	((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
 
-#define __clamp_once(val, lo, hi, uval, ulo, uhi) ({				\
-	__auto_type uval = (val);						\
-	__auto_type ulo = (lo);							\
-	__auto_type uhi = (hi);							\
+#define __clamp_once(type, val, lo, hi, uval, ulo, uhi) ({			\
+	type uval = (val);							\
+	type ulo = (lo);							\
+	type uhi = (hi);							\
 	BUILD_BUG_ON_MSG(statically_true(ulo > uhi),				\
 		"clamp() low limit " #lo " greater than high limit " #hi);	\
 	BUILD_BUG_ON_MSG(!__types_ok3(uval, ulo, uhi),				\
 		"clamp("#val", "#lo", "#hi") signedness error");		\
 	__clamp(uval, ulo, uhi); })
 
-#define __careful_clamp(val, lo, hi) \
-	__clamp_once(val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
+#define __careful_clamp(type, val, lo, hi) \
+	__clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
 
 /**
- * clamp - return a value clamped to a given range with strict typechecking
+ * clamp - return a value clamped to a given range with typechecking
  * @val: current value
  * @lo: lowest allowable value
  * @hi: highest allowable value
  *
- * This macro does strict typechecking of @lo/@hi to make sure they are of the
- * same type as @val.  See the unnecessary pointer comparisons.
+ * This macro checks @val/@lo/@hi to make sure they have compatible
+ * signedness.
  */
-#define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
+#define clamp(val, lo, hi) __careful_clamp(__auto_type, val, lo, hi)
 
 /**
  * clamp_t - return a value clamped to a given range using a given type
@@ -217,7 +217,7 @@
  * This macro does no typechecking and uses temporary variables of type
  * @type to make all the comparisons.
  */
-#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
+#define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
 
 /**
  * clamp_val - return a value clamped to a given range using val's type
@@ -230,7 +230,7 @@
  * type and @lo and @hi are literals that will otherwise be assigned a signed
  * integer type.
  */
-#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
+#define clamp_val(val, lo, hi) __careful_clamp(typeof(val), val, lo, hi)
 
 /*
  * Do not check the array parameter using __must_be_array().
-- 
2.47.3

[PATCH v2 27/27 5.10.y] minmax.h: remove some #defines that are only expanded once

[Eliav Farber]

From: David Laight <David.Laight@ACULAB.COM>

[ Upstream commit 2b97aaf74ed534fb838d09867d09a3ca5d795208 ]

The bodies of __signed_type_use() and __unsigned_type_use() are much the
same size as their names - so put the bodies in the only line that expands
them.

Similarly __signed_type() is defined separately for 64bit and then used
exactly once just below.

Change the test for __signed_type from CONFIG_64BIT to one based on gcc
defined macros so that the code is valid if it gets used outside of a
kernel build.

Link: https://lkml.kernel.org/r/9386d1ebb8974fbabbed2635160c3975@AcuMS.aculab.com
Signed-off-by: David Laight <david.laight@aculab.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eliav Farber <farbere@amazon.com>
---
 include/linux/minmax.h | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 2bbdd5b5e07e..eaaf5c008e4d 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -46,10 +46,8 @@
  * comparison, and these expressions only need to be careful to not cause
  * warnings for pointer use.
  */
-#define __signed_type_use(ux) (2 + __is_nonneg(ux))
-#define __unsigned_type_use(ux) (1 + 2 * (sizeof(ux) < 4))
 #define __sign_use(ux) (is_signed_type(typeof(ux)) ? \
-	__signed_type_use(ux) : __unsigned_type_use(ux))
+	(2 + __is_nonneg(ux)) : (1 + 2 * (sizeof(ux) < 4)))
 
 /*
  * Check whether a signed value is always non-negative.
@@ -57,7 +55,7 @@
  * A cast is needed to avoid any warnings from values that aren't signed
  * integer types (in which case the result doesn't matter).
  *
- * On 64-bit any integer or pointer type can safely be cast to 'long'.
+ * On 64-bit any integer or pointer type can safely be cast to 'long long'.
  * But on 32-bit we need to avoid warnings about casting pointers to integers
  * of different sizes without truncating 64-bit values so 'long' or 'long long'
  * must be used depending on the size of the value.
@@ -66,12 +64,12 @@
  * them, but we do not use s128 types in the kernel (we do use 'u128',
  * but they are handled by the !is_signed_type() case).
  */
-#ifdef CONFIG_64BIT
-  #define __signed_type(ux) long
+#if __SIZEOF_POINTER__ == __SIZEOF_LONG_LONG__
+#define __is_nonneg(ux) statically_true((long long)(ux) >= 0)
 #else
-  #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L))
+#define __is_nonneg(ux) statically_true( \
+	(typeof(__builtin_choose_expr(sizeof(ux) > 4, 1LL, 1L)))(ux) >= 0)
 #endif
-#define __is_nonneg(ux) statically_true((__signed_type(ux))(ux) >= 0)
 
 #define __types_ok(ux, uy) \
 	(__sign_use(ux) & __sign_use(uy))
-- 
2.47.3

Re: [PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once

[Greg KH]

On Fri, Oct 17, 2025 at 09:04:53AM +0000, Eliav Farber wrote:
> From: Bart Van Assche <bvanassche@acm.org>
> 
> [ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]

This isn't in 5.15.y, why is it needed in 5.10.y?

thanks,

greg k-h

RE: [PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once

[Farber, Eliav]

> On Fri, Oct 17, 2025 at 09:04:53AM +0000, Eliav Farber wrote:
> > From: Bart Van Assche <bvanassche@acm.org>
> >
> > [ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]
>
> This isn't in 5.15.y, why is it needed in 5.10.y?

This is the mainline commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/overflow.h?h=v6.18-rc1&id=92d23c6e94157739b997cacce151586a0d07bb8a

The commit hash is 92d23c6e94157739b997cacce151586a0d07bb8a, which is
the one I used for the backport.

And here is the corresponding commit in the 5.15.y branch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/include/linux/overflow.h?h=v5.15.194&id=ed6e37e30826b12572636c6bbfe6319233690c90
However, the commit message there references a different hash:
a49a64b5bf195381c09202c524f0f84b5f3e816f.

---
Regards, Eliav

Re: [PATCH v2 01/27 5.10.y] overflow, tracing: Define the is_signed_type() macro once

[Greg KH]

On Fri, Oct 17, 2025 at 12:16:27PM +0000, Farber, Eliav wrote:
> > On Fri, Oct 17, 2025 at 09:04:53AM +0000, Eliav Farber wrote:
> > > From: Bart Van Assche <bvanassche@acm.org>
> > >
> > > [ Upstream commit 92d23c6e94157739b997cacce151586a0d07bb8a ]
> >
> > This isn't in 5.15.y, why is it needed in 5.10.y?
> 
> This is the mainline commit:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/linux/overflow.h?h=v6.18-rc1&id=92d23c6e94157739b997cacce151586a0d07bb8a
> 
> The commit hash is 92d23c6e94157739b997cacce151586a0d07bb8a, which is
> the one I used for the backport.
> 
> And here is the corresponding commit in the 5.15.y branch:
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/include/linux/overflow.h?h=v5.15.194&id=ed6e37e30826b12572636c6bbfe6319233690c90
> However, the commit message there references a different hash:
> a49a64b5bf195381c09202c524f0f84b5f3e816f.

Ugh, that hash is invalid, I missed that :(

Thanks for the info, I'll go work on queueing these up.

greg k-h

Re: [PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[Greg KH]

On Fri, Oct 17, 2025 at 09:04:52AM +0000, Eliav Farber wrote:
> This series backports 27 patches to update minmax.h in the 5.10.y
> branch, aligning it with v6.17-rc7.
> 
> The ultimate goal is to synchronize all long-term branches so that they
> include the full set of minmax.h changes.
> 
> - 6.12.y has already been backported; the changes are included in
>   v6.12.49.
> - 6.6.y has already been backported; the changes are included in
>   v6.6.109.
> - 6.1.y has already been backported; the changes are currently in the
>   6.1-stable tree.
> - 5.15.y has already been backported; the changes are currently in the
>   5.15-stable tree.

With this series applied, on an arm64 server, building 'allmodconfig', I
get the following build error.

Oddly I don't see it on my x86 server, perhaps due to different compiler
versions?

Any ideas?

thanks,

greg k-h

------------------------

In function ‘rt2800_txpower_to_dev’,
    inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4022:25:
./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
  309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                             ^
./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
  290 |                         prefix ## suffix();                             \
      |                         ^~~~~~
./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
  309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |         ^~~~~~~~~~~~~~~~~~~
../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
   39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
      |                                     ^~~~~~~~~~~~~~~~~~
../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
      |         ^~~~~~~~~~~~~~~~
../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
  195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
      |         ^~~~~~~~~~~~
../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
  218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
      |                                    ^~~~~~~~~~~~~~~
../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
 3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
      |                        ^~~~~~~
In function ‘rt2800_txpower_to_dev’,
    inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4024:25:
./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
  309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                             ^
./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
  290 |                         prefix ## suffix();                             \
      |                         ^~~~~~
./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
  309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |         ^~~~~~~~~~~~~~~~~~~
../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
   39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
      |                                     ^~~~~~~~~~~~~~~~~~
../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
      |         ^~~~~~~~~~~~~~~~
../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
  195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
      |         ^~~~~~~~~~~~
../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
  218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
      |                                    ^~~~~~~~~~~~~~~
../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
 3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
      |                        ^~~~~~~
In function ‘rt2800_txpower_to_dev’,
    inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4028:4:
./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
  309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                             ^
./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
  290 |                         prefix ## suffix();                             \
      |                         ^~~~~~
./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
  309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |         ^~~~~~~~~~~~~~~~~~~
../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
   39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
      |                                     ^~~~~~~~~~~~~~~~~~
../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
      |         ^~~~~~~~~~~~~~~~
../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
  195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
      |         ^~~~~~~~~~~~
../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
  218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
      |                                    ^~~~~~~~~~~~~~~
../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
 3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
      |                        ^~~~~~~
make[6]: *** [../scripts/Makefile.build:286: drivers/net/wireless/ralink/rt2x00/rt2800lib.o] Error 1
make[5]: *** [../scripts/Makefile.build:503: drivers/net/wireless/ralink/rt2x00] Error 2
make[4]: *** [../scripts/Makefile.build:503: drivers/net/wireless/ralink] Error 2
make[4]: *** Waiting for unfinished jobs....

Re: [PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[Nathan Chancellor]

On Fri, Oct 17, 2025 at 05:03:02PM +0200, Greg KH wrote:
> On Fri, Oct 17, 2025 at 09:04:52AM +0000, Eliav Farber wrote:
> > This series backports 27 patches to update minmax.h in the 5.10.y
> > branch, aligning it with v6.17-rc7.
> > 
> > The ultimate goal is to synchronize all long-term branches so that they
> > include the full set of minmax.h changes.
> > 
> > - 6.12.y has already been backported; the changes are included in
> >   v6.12.49.
> > - 6.6.y has already been backported; the changes are included in
> >   v6.6.109.
> > - 6.1.y has already been backported; the changes are currently in the
> >   6.1-stable tree.
> > - 5.15.y has already been backported; the changes are currently in the
> >   5.15-stable tree.
> 
> With this series applied, on an arm64 server, building 'allmodconfig', I
> get the following build error.
> 
> Oddly I don't see it on my x86 server, perhaps due to different compiler
> versions?
> 
> Any ideas?
> 
> thanks,
> 
> greg k-h
> 
> ------------------------
> 
> In function ‘rt2800_txpower_to_dev’,
>     inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4022:25:
> ./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                             ^
> ./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
>   290 |                         prefix ## suffix();                             \
>       |                         ^~~~~~
> ./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |         ^~~~~~~~~~~~~~~~~~~
> ../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
> ../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>   188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
>       |         ^~~~~~~~~~~~~~~~
> ../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
>   195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
>       |         ^~~~~~~~~~~~
> ../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
>   218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
>       |                                    ^~~~~~~~~~~~~~~
> ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
>  3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
>       |                        ^~~~~~~

Missing commit 3bc753c06dd0 ("kbuild: treat char as always unsigned")?

Cheers,
Nathan

RE: [PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[Farber, Eliav]

> On Fri, Oct 17, 2025 at 09:04:52AM +0000, Eliav Farber wrote:
> > This series backports 27 patches to update minmax.h in the 5.10.y
> > branch, aligning it with v6.17-rc7.
> >
> > The ultimate goal is to synchronize all long-term branches so that they
> > include the full set of minmax.h changes.
> >
> > - 6.12.y has already been backported; the changes are included in
> >   v6.12.49.
> > - 6.6.y has already been backported; the changes are included in
> >   v6.6.109.
> > - 6.1.y has already been backported; the changes are currently in the
> >   6.1-stable tree.
> > - 5.15.y has already been backported; the changes are currently in the
> >   5.15-stable tree.
>
> With this series applied, on an arm64 server, building 'allmodconfig', I
> get the following build error.
>
> Oddly I don't see it on my x86 server, perhaps due to different compiler
> versions?
>
> Any ideas?

This mainline commit is missing:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/wireless/ralink/rt2x00/rt2800lib.c?h=v6.18-rc1&id=66063033f77e10b985258126a97573f84bb8d3b4

This fix already exists in 5.15.y:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/net/wireless/ralink/rt2x00/rt2800lib.c?h=v5.15.194&id=2d3cef3d7a5df260a14a6679c4aca0c97e570ee5
…but is missing in 5.10.y.

I now backported it to 5.10.y here:
https://lore.kernel.org/stable/20251018195945.18825-1-farbere@amazon.com/T/#u

Regards, Eliav


> In function ‘rt2800_txpower_to_dev’,
>     inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4022:25:
>./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                             ^
>./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
>   290 |                         prefix ## suffix();                             \
>       |                         ^~~~~~
>./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |         ^~~~~~~~~~~~~~~~~~~
>../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
>../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>   188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
>       |         ^~~~~~~~~~~~~~~~
>../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
>   195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
>       |         ^~~~~~~~~~~~
>../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
>   218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
>       |                                    ^~~~~~~~~~~~~~~
>../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
>  3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
>       |                        ^~~~~~~
> In function ‘rt2800_txpower_to_dev’,
>     inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4024:25:
>./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                             ^
>./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
>   290 |                         prefix ## suffix();                             \
>       |                         ^~~~~~
>./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |         ^~~~~~~~~~~~~~~~~~~
>../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
>../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>   188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
>       |         ^~~~~~~~~~~~~~~~
>../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
>   195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
>       |         ^~~~~~~~~~~~
>../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
>   218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
>       |                                    ^~~~~~~~~~~~~~~
>../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
>  3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
>       |                        ^~~~~~~
> In function ‘rt2800_txpower_to_dev’,
>     inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4028:4:
>./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |                                             ^
>./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
>   290 |                         prefix ## suffix();                             \
>       |                         ^~~~~~
>./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
>   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>       |         ^~~~~~~~~~~~~~~~~~~
>../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
>    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>       |                                     ^~~~~~~~~~~~~~~~~~
>../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
>   188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
>       |         ^~~~~~~~~~~~~~~~
>../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
>   195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
>       |         ^~~~~~~~~~~~
>../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
>   218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
>       |                                    ^~~~~~~~~~~~~~~
>../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
>  3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
>       |                        ^~~~~~~
> make[6]: *** [../scripts/Makefile.build:286: drivers/net/wireless/ralink/rt2x00/rt2800lib.o] Error 1
> make[5]: *** [../scripts/Makefile.build:503: drivers/net/wireless/ralink/rt2x00] Error 2
> make[4]: *** [../scripts/Makefile.build:503: drivers/net/wireless/ralink] Error 2
> make[4]: *** Waiting for unfinished jobs....

Re: [PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[Greg KH]

On Sat, Oct 18, 2025 at 08:07:32PM +0000, Farber, Eliav wrote:
> > On Fri, Oct 17, 2025 at 09:04:52AM +0000, Eliav Farber wrote:
> > > This series backports 27 patches to update minmax.h in the 5.10.y
> > > branch, aligning it with v6.17-rc7.
> > >
> > > The ultimate goal is to synchronize all long-term branches so that they
> > > include the full set of minmax.h changes.
> > >
> > > - 6.12.y has already been backported; the changes are included in
> > >   v6.12.49.
> > > - 6.6.y has already been backported; the changes are included in
> > >   v6.6.109.
> > > - 6.1.y has already been backported; the changes are currently in the
> > >   6.1-stable tree.
> > > - 5.15.y has already been backported; the changes are currently in the
> > >   5.15-stable tree.
> >
> > With this series applied, on an arm64 server, building 'allmodconfig', I
> > get the following build error.
> >
> > Oddly I don't see it on my x86 server, perhaps due to different compiler
> > versions?
> >
> > Any ideas?
> 
> This mainline commit is missing:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/wireless/ralink/rt2x00/rt2800lib.c?h=v6.18-rc1&id=66063033f77e10b985258126a97573f84bb8d3b4
> 
> This fix already exists in 5.15.y:
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/net/wireless/ralink/rt2x00/rt2800lib.c?h=v5.15.194&id=2d3cef3d7a5df260a14a6679c4aca0c97e570ee5
> …but is missing in 5.10.y.
> 
> I now backported it to 5.10.y here:
> https://lore.kernel.org/stable/20251018195945.18825-1-farbere@amazon.com/T/#u

Thanks,I've queued that up now.

greg k-h

Re: [PATCH v2 00/27 5.10.y] Backport minmax.h updates from v6.17-rc7

[Greg KH]

On Fri, Oct 17, 2025 at 05:09:24PM +0100, Nathan Chancellor wrote:
> On Fri, Oct 17, 2025 at 05:03:02PM +0200, Greg KH wrote:
> > On Fri, Oct 17, 2025 at 09:04:52AM +0000, Eliav Farber wrote:
> > > This series backports 27 patches to update minmax.h in the 5.10.y
> > > branch, aligning it with v6.17-rc7.
> > > 
> > > The ultimate goal is to synchronize all long-term branches so that they
> > > include the full set of minmax.h changes.
> > > 
> > > - 6.12.y has already been backported; the changes are included in
> > >   v6.12.49.
> > > - 6.6.y has already been backported; the changes are included in
> > >   v6.6.109.
> > > - 6.1.y has already been backported; the changes are currently in the
> > >   6.1-stable tree.
> > > - 5.15.y has already been backported; the changes are currently in the
> > >   5.15-stable tree.
> > 
> > With this series applied, on an arm64 server, building 'allmodconfig', I
> > get the following build error.
> > 
> > Oddly I don't see it on my x86 server, perhaps due to different compiler
> > versions?
> > 
> > Any ideas?
> > 
> > thanks,
> > 
> > greg k-h
> > 
> > ------------------------
> > 
> > In function ‘rt2800_txpower_to_dev’,
> >     inlined from ‘rt2800_config_channel’ at ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:4022:25:
> > ./../include/linux/compiler_types.h:309:45: error: call to ‘__compiletime_assert_1168’ declared with attribute error: clamp() low limit -7 greater than high limit 15
> >   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> >       |                                             ^
> > ./../include/linux/compiler_types.h:290:25: note: in definition of macro ‘__compiletime_assert’
> >   290 |                         prefix ## suffix();                             \
> >       |                         ^~~~~~
> > ./../include/linux/compiler_types.h:309:9: note: in expansion of macro ‘_compiletime_assert’
> >   309 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> >       |         ^~~~~~~~~~~~~~~~~~~
> > ../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
> >    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> >       |                                     ^~~~~~~~~~~~~~~~~~
> > ../include/linux/minmax.h:188:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
> >   188 |         BUILD_BUG_ON_MSG(statically_true(ulo > uhi),                            \
> >       |         ^~~~~~~~~~~~~~~~
> > ../include/linux/minmax.h:195:9: note: in expansion of macro ‘__clamp_once’
> >   195 |         __clamp_once(type, val, lo, hi, __UNIQUE_ID(v_), __UNIQUE_ID(l_), __UNIQUE_ID(h_))
> >       |         ^~~~~~~~~~~~
> > ../include/linux/minmax.h:218:36: note: in expansion of macro ‘__careful_clamp’
> >   218 | #define clamp_t(type, val, lo, hi) __careful_clamp(type, val, lo, hi)
> >       |                                    ^~~~~~~~~~~~~~~
> > ../drivers/net/wireless/ralink/rt2x00/rt2800lib.c:3980:24: note: in expansion of macro ‘clamp_t’
> >  3980 |                 return clamp_t(char, txpower, MIN_A_TXPOWER, MAX_A_TXPOWER);
> >       |                        ^~~~~~~
> 
> Missing commit 3bc753c06dd0 ("kbuild: treat char as always unsigned")?

That's going to be messy to backport, it's not even in 6.1.y, so let's
leave that alone if at all possible.

thanks,

greg k-h