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authorKent Overstreet <kent.overstreet@linux.dev>2023-10-24 14:46:58 -0400
committerKent Overstreet <kent.overstreet@linux.dev>2023-10-30 21:48:22 -0400
commit2bce6368c46b835a133f7f4946eea9c4513828dd (patch)
tree9ddb4e9e192a1cb25c27d9b29641d2650be8f718 /lib
parentcd063c8b9e1e95560e90bac7816234d8b2ee2897 (diff)
closures: Better memory barriers
atomic_(dec|sub)_return_release() are a thing now - use them. Also, delete the useless barrier in set_closure_fn(): it's redundant with the memory barrier in closure_put(0. Since closure_put() would now otherwise just have a release barrier, we also need a new barrier when the ref hits 0 - smp_acquire__after_ctrl_dep(). Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'lib')
-rw-r--r--lib/closure.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/lib/closure.c b/lib/closure.c
index 0855e698ced1..501dfa277b59 100644
--- a/lib/closure.c
+++ b/lib/closure.c
@@ -21,6 +21,8 @@ static inline void closure_put_after_sub(struct closure *cl, int flags)
BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR));
if (!r) {
+ smp_acquire__after_ctrl_dep();
+
if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) {
atomic_set(&cl->remaining,
CLOSURE_REMAINING_INITIALIZER);
@@ -43,7 +45,7 @@ static inline void closure_put_after_sub(struct closure *cl, int flags)
/* For clearing flags with the same atomic op as a put */
void closure_sub(struct closure *cl, int v)
{
- closure_put_after_sub(cl, atomic_sub_return(v, &cl->remaining));
+ closure_put_after_sub(cl, atomic_sub_return_release(v, &cl->remaining));
}
EXPORT_SYMBOL(closure_sub);
@@ -52,7 +54,7 @@ EXPORT_SYMBOL(closure_sub);
*/
void closure_put(struct closure *cl)
{
- closure_put_after_sub(cl, atomic_dec_return(&cl->remaining));
+ closure_put_after_sub(cl, atomic_dec_return_release(&cl->remaining));
}
EXPORT_SYMBOL(closure_put);