diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2019-11-08 17:08:57 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-11-11 09:03:31 +0100 |
| commit | feb4a51323babe13315c3b783ea7f1cf25368918 (patch) | |
| tree | 5ff36d9d23ddfc23be5bee4caf1c7cb6b8242024 /kernel | |
| parent | irq_work: Fix irq_work_claim() memory ordering (diff) | |
| download | linux-feb4a51323babe13315c3b783ea7f1cf25368918.tar.xz linux-feb4a51323babe13315c3b783ea7f1cf25368918.zip | |
irq_work: Slightly simplify IRQ_WORK_PENDING clearing
Instead of fetching the value of flags and perform an xchg() to clear
a bit, just use atomic_fetch_andnot() that is more suitable to do that
job in one operation while keeping the full ordering.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191108160858.31665-4-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq_work.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 255454a48346..49c53f80a13a 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -34,7 +34,7 @@ static bool irq_work_claim(struct irq_work *work) oflags = atomic_fetch_or(IRQ_WORK_CLAIMED, &work->flags); /* * If the work is already pending, no need to raise the IPI. - * The pairing atomic_xchg() in irq_work_run() makes sure + * The pairing atomic_fetch_andnot() in irq_work_run() makes sure * everything we did before is visible. */ if (oflags & IRQ_WORK_PENDING) @@ -135,7 +135,6 @@ static void irq_work_run_list(struct llist_head *list) { struct irq_work *work, *tmp; struct llist_node *llnode; - int flags; BUG_ON(!irqs_disabled()); @@ -144,6 +143,7 @@ static void irq_work_run_list(struct llist_head *list) llnode = llist_del_all(list); llist_for_each_entry_safe(work, tmp, llnode, llnode) { + int flags; /* * Clear the PENDING bit, after this point the @work * can be re-used. @@ -151,8 +151,7 @@ static void irq_work_run_list(struct llist_head *list) * to claim that work don't rely on us to handle their data * while we are in the middle of the func. */ - flags = atomic_read(&work->flags) & ~IRQ_WORK_PENDING; - atomic_xchg(&work->flags, flags); + flags = atomic_fetch_andnot(IRQ_WORK_PENDING, &work->flags); work->func(work); /* |