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authorFrederic Weisbecker <frederic@kernel.org>2019-11-08 17:08:55 +0100
committerIngo Molnar <mingo@kernel.org>2019-11-11 09:02:56 +0100
commit153bedbac2ebd475e1c7c2d2fa0c042f5525927d (patch)
tree80be4ee2af1d7aa3cc52be50c225f32002dd2dad /kernel/irq_work.c
parent31f4f5b495a62c9a8b15b1c3581acd5efeb9af8c (diff)
irq_work: Convert flags to atomic_t
We need to convert flags to atomic_t in order to later fix an ordering issue on atomic_cmpxchg() failure. This will allow us to use atomic_fetch_or(). Also clarify the nature of those flags. [ mingo: Converted two more usage site the original patch missed. ] 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/20191108160858.31665-2-frederic@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/irq_work.c')
-rw-r--r--kernel/irq_work.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index d42acaf81886..df0dbf4d859b 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -29,16 +29,16 @@ static DEFINE_PER_CPU(struct llist_head, lazy_list);
*/
static bool irq_work_claim(struct irq_work *work)
{
- unsigned long flags, oflags, nflags;
+ int flags, oflags, nflags;
/*
* Start with our best wish as a premise but only trust any
* flag value after cmpxchg() result.
*/
- flags = work->flags & ~IRQ_WORK_PENDING;
+ flags = atomic_read(&work->flags) & ~IRQ_WORK_PENDING;
for (;;) {
nflags = flags | IRQ_WORK_CLAIMED;
- oflags = cmpxchg(&work->flags, flags, nflags);
+ oflags = atomic_cmpxchg(&work->flags, flags, nflags);
if (oflags == flags)
break;
if (oflags & IRQ_WORK_PENDING)
@@ -61,7 +61,7 @@ void __weak arch_irq_work_raise(void)
static void __irq_work_queue_local(struct irq_work *work)
{
/* If the work is "lazy", handle it from next tick if any */
- if (work->flags & IRQ_WORK_LAZY) {
+ if (atomic_read(&work->flags) & IRQ_WORK_LAZY) {
if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
tick_nohz_tick_stopped())
arch_irq_work_raise();
@@ -143,7 +143,7 @@ static void irq_work_run_list(struct llist_head *list)
{
struct irq_work *work, *tmp;
struct llist_node *llnode;
- unsigned long flags;
+ int flags;
BUG_ON(!irqs_disabled());
@@ -159,15 +159,15 @@ 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 = work->flags & ~IRQ_WORK_PENDING;
- xchg(&work->flags, flags);
+ flags = atomic_read(&work->flags) & ~IRQ_WORK_PENDING;
+ atomic_xchg(&work->flags, flags);
work->func(work);
/*
* Clear the BUSY bit and return to the free state if
* no-one else claimed it meanwhile.
*/
- (void)cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
+ (void)atomic_cmpxchg(&work->flags, flags, flags & ~IRQ_WORK_BUSY);
}
}
@@ -199,7 +199,7 @@ void irq_work_sync(struct irq_work *work)
{
lockdep_assert_irqs_enabled();
- while (work->flags & IRQ_WORK_BUSY)
+ while (atomic_read(&work->flags) & IRQ_WORK_BUSY)
cpu_relax();
}
EXPORT_SYMBOL_GPL(irq_work_sync);