[PATCH 5.15.y 0/8] Backport patches for DAMON merge regions fix

[PATCH 5.15.y 0/8] Backport patches for DAMON merge regions fix

[SeongJae Park]

Commit 310d6c15e910 ("mm/damon/core: merge regions aggressively when
max_nr_regions") causes a build warning and a build failure [1] on
5.15.y.  Those are due to
1) unnecessarily strict type check from max(), and
2) use of not-yet-introduced damon_ctx->attrs field, respectively.

Fix the warning by backporting a minmax.h upstream commit that made the
type check less strict for unnecessary case, and upstream commits that
it depends on.

Note that all patches except the fourth one ("minmax: fix header
inclusions") are clean cherry-picks of upstream commit.  For the fourth
one, minor conflict resolving was needed.

Also, the last patch, which is the backport of the DAMON fix, was
cleanly cherry-picked, but added manual fix for the build failure.

[1] https://lore.kernel.org/2024071532-pebble-jailhouse-48b2@gregkh

Andy Shevchenko (1):
  minmax: fix header inclusions

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

David Laight (3):
  minmax: allow min()/max()/clamp() if the arguments have the same
    signedness.
  minmax: allow comparisons of 'int' against 'unsigned char/short'
  minmax: relax check to allow comparison between unsigned arguments and
    signed constants

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

SeongJae Park (1):
  mm/damon/core: merge regions aggressively when max_nr_regions is unmet

 include/linux/compiler.h     |  6 +++
 include/linux/minmax.h       | 89 ++++++++++++++++++++++++++----------
 include/linux/overflow.h     |  1 -
 include/linux/trace_events.h |  2 -
 mm/damon/core.c              | 23 ++++++++--
 5 files changed, 90 insertions(+), 31 deletions(-)


base-commit: 4d1b7f1bf3858ed48a98c004bda5fdff2cdf13c8
-- 
2.39.2

[PATCH 5.15.y 1/8] tracing: Define the is_signed_type() macro once

[SeongJae Park]

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

commit a49a64b5bf195381c09202c524f0f84b5f3e816f upstream.

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, 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.

Link: https://lore.kernel.org/all/CAHk-=whjH6p+qzwUdx5SOVVHjS3WvzJQr6mDUwhEyTf6pJWzaQ@mail.gmail.com/
Link: https://lore.kernel.org/all/CAHk-=wjQGnVfb4jehFR0XyZikdQvCZouE96xR_nnf5kqaM5qqQ@mail.gmail.com/
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit a49a64b5bf195381c09202c524f0f84b5f3e816f)
Signed-off-by: SeongJae Park <sj@kernel.org>
---
 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 0f7fd205ab7e..65111de4ad6b 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -246,6 +246,12 @@ 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 17575aa2a53c..511c43ce9421 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -801,8 +801,6 @@ 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,
-- 
2.39.2

Re: [PATCH 5.15.y 0/8] Backport patches for DAMON merge regions fix

[Greg KH]

On Tue, Jul 16, 2024 at 11:33:25AM -0700, SeongJae Park wrote:
> Commit 310d6c15e910 ("mm/damon/core: merge regions aggressively when
> max_nr_regions") causes a build warning and a build failure [1] on
> 5.15.y.  Those are due to
> 1) unnecessarily strict type check from max(), and
> 2) use of not-yet-introduced damon_ctx->attrs field, respectively.
> 
> Fix the warning by backporting a minmax.h upstream commit that made the
> type check less strict for unnecessary case, and upstream commits that
> it depends on.
> 
> Note that all patches except the fourth one ("minmax: fix header
> inclusions") are clean cherry-picks of upstream commit.  For the fourth
> one, minor conflict resolving was needed.
> 
> Also, the last patch, which is the backport of the DAMON fix, was
> cleanly cherry-picked, but added manual fix for the build failure.
> 
> [1] https://lore.kernel.org/2024071532-pebble-jailhouse-48b2@gregkh

All now queued up, again, thank you for the minmax backports, much
appreciated.

greg k-h