[PATCH v3 08/15] futex: Propagate flags into get_futex_key()

peterz
2023-09-21T20:15:57Z

[-- Attachment #1: peterz-futex2-get_futex_key-flags.patch --]
[-- Type: text/plain, Size: 5603 bytes --]

Instead of only passing FLAGS_SHARED as a boolean, pass down flags as
a whole.

No functional change intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/futex/core.c | 5 ++++-
kernel/futex/futex.h | 2 +-
kernel/futex/pi.c | 4 ++--
kernel/futex/requeue.c | 6 +++---
kernel/futex/waitwake.c | 14 +++++++-------
5 files changed, 17 insertions(+), 14 deletions(-)

Index: linux-2.6/kernel/futex/core.c
===================================================================
--- linux-2.6.orig/kernel/futex/core.c
+++ linux-2.6/kernel/futex/core.c
@@ -193,7 +193,7 @@ static u64 get_inode_sequence_number(str
/**
* get_futex_key() - Get parameters which are the keys for a futex
* @uaddr: virtual address of the futex
- * @fshared: false for a PROCESS_PRIVATE futex, true for PROCESS_SHARED
+ * @flags: FLAGS_*
* @key: address where result is stored.
* @rw: mapping needs to be read/write (values: FUTEX_READ,
* FUTEX_WRITE)
@@ -217,7 +217,7 @@ static u64 get_inode_sequence_number(str
*
* lock_page() might sleep, the caller should not hold a spinlock.
*/
-int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key,
+int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key,
enum futex_access rw)
{
unsigned long address = (unsigned long)uaddr;
@@ -226,6 +226,9 @@ int get_futex_key(u32 __user *uaddr, boo
struct folio *folio;
struct address_space *mapping;
int err, ro = 0;
+ bool fshared;
+
+ fshared = flags & FLAGS_SHARED;

/*
* The futex address must be "naturally" aligned.
Index: linux-2.6/kernel/futex/futex.h
===================================================================
--- linux-2.6.orig/kernel/futex/futex.h
+++ linux-2.6/kernel/futex/futex.h
@@ -184,7 +184,7 @@ enum futex_access {
FUTEX_WRITE
};

-extern int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key,
+extern int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key,
enum futex_access rw);

extern struct hrtimer_sleeper *
Index: linux-2.6/kernel/futex/pi.c
===================================================================
--- linux-2.6.orig/kernel/futex/pi.c
+++ linux-2.6/kernel/futex/pi.c
@@ -933,7 +933,7 @@ int futex_lock_pi(u32 __user *uaddr, uns
to = futex_setup_timer(time, &timeout, flags, 0);

retry:
- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, FUTEX_WRITE);
+ ret = get_futex_key(uaddr, flags, &q.key, FUTEX_WRITE);
if (unlikely(ret != 0))
goto out;

@@ -1129,7 +1129,7 @@ retry:
if ((uval & FUTEX_TID_MASK) != vpid)
return -EPERM;

- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_WRITE);
+ ret = get_futex_key(uaddr, flags, &key, FUTEX_WRITE);
if (ret)
return ret;

Index: linux-2.6/kernel/futex/requeue.c
===================================================================
--- linux-2.6.orig/kernel/futex/requeue.c
+++ linux-2.6/kernel/futex/requeue.c
@@ -424,10 +424,10 @@ int futex_requeue(u32 __user *uaddr1, un
}

retry:
- ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
+ ret = get_futex_key(uaddr1, flags, &key1, FUTEX_READ);
if (unlikely(ret != 0))
return ret;
- ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2,
+ ret = get_futex_key(uaddr2, flags, &key2,
requeue_pi ? FUTEX_WRITE : FUTEX_READ);
if (unlikely(ret != 0))
return ret;
@@ -789,7 +789,7 @@ int futex_wait_requeue_pi(u32 __user *ua
*/
rt_mutex_init_waiter(&rt_waiter);

- ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
+ ret = get_futex_key(uaddr2, flags, &key2, FUTEX_WRITE);
if (unlikely(ret != 0))
goto out;

Index: linux-2.6/kernel/futex/waitwake.c
===================================================================
--- linux-2.6.orig/kernel/futex/waitwake.c
+++ linux-2.6/kernel/futex/waitwake.c
@@ -145,13 +145,13 @@ int futex_wake(u32 __user *uaddr, unsign
struct futex_hash_bucket *hb;
struct futex_q *this, *next;
union futex_key key = FUTEX_KEY_INIT;
- int ret;
DEFINE_WAKE_Q(wake_q);
+ int ret;

if (!bitset)
return -EINVAL;

- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &key, FUTEX_READ);
+ ret = get_futex_key(uaddr, flags, &key, FUTEX_READ);
if (unlikely(ret != 0))
return ret;

@@ -248,10 +248,10 @@ int futex_wake_op(u32 __user *uaddr1, un
DEFINE_WAKE_Q(wake_q);

retry:
- ret = get_futex_key(uaddr1, flags & FLAGS_SHARED, &key1, FUTEX_READ);
+ ret = get_futex_key(uaddr1, flags, &key1, FUTEX_READ);
if (unlikely(ret != 0))
return ret;
- ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
+ ret = get_futex_key(uaddr2, flags, &key2, FUTEX_WRITE);
if (unlikely(ret != 0))
return ret;

@@ -426,7 +426,7 @@ retry:
continue;

ret = get_futex_key(u64_to_user_ptr(vs[i].w.uaddr),
- vs[i].w.flags & FLAGS_SHARED,
+ vs[i].w.flags,
&vs[i].q.key, FUTEX_READ);

if (unlikely(ret))
@@ -438,7 +438,7 @@ retry:
for (i = 0; i < count; i++) {
u32 __user *uaddr = (u32 __user *)(unsigned long)vs[i].w.uaddr;
struct futex_q *q = &vs[i].q;
- u32 val = (u32)vs[i].w.val;
+ u32 val = vs[i].w.val;

hb = futex_q_lock(q);
ret = futex_get_value_locked(&uval, uaddr);
@@ -602,7 +602,7 @@ int futex_wait_setup(u32 __user *uaddr,
* while the syscall executes.
*/
retry:
- ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q->key, FUTEX_READ);
+ ret = get_futex_key(uaddr, flags, &q->key, FUTEX_READ);
if (unlikely(ret != 0))
return ret;