diff mbox series

[net-next,4/6] net: adopt try_cmpxchg() in napi_schedule_prep() and napi_complete_done()

Message ID 20221115091101.2234482-5-edumazet@google.com (mailing list archive)
State Accepted
Commit 1462160c7455cfc495693e47d0eabb371ec4f7ff
Delegated to: Netdev Maintainers
Headers show
Series net: more try_cmpxchg() conversions | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers warning 1 maintainers not CCed: petrm@nvidia.com
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 37 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Nov. 15, 2022, 9:10 a.m. UTC 
This makes the code slightly more efficient.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/dev.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index 10b56648a9d4a0a709f8e23bb3e114854a4a1b69..0c12c7ad04f21da05fef4c60ca5570bff48ec491 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5979,10 +5979,9 @@  EXPORT_SYMBOL(__napi_schedule);
  */
 bool napi_schedule_prep(struct napi_struct *n)
 {
-	unsigned long val, new;
+	unsigned long new, val = READ_ONCE(n->state);
 
 	do {
-		val = READ_ONCE(n->state);
 		if (unlikely(val & NAPIF_STATE_DISABLE))
 			return false;
 		new = val | NAPIF_STATE_SCHED;
@@ -5995,7 +5994,7 @@  bool napi_schedule_prep(struct napi_struct *n)
 		 */
 		new |= (val & NAPIF_STATE_SCHED) / NAPIF_STATE_SCHED *
 						   NAPIF_STATE_MISSED;
-	} while (cmpxchg(&n->state, val, new) != val);
+	} while (!try_cmpxchg(&n->state, &val, new));
 
 	return !(val & NAPIF_STATE_SCHED);
 }
@@ -6063,9 +6062,8 @@  bool napi_complete_done(struct napi_struct *n, int work_done)
 		local_irq_restore(flags);
 	}
 
+	val = READ_ONCE(n->state);
 	do {
-		val = READ_ONCE(n->state);
-
 		WARN_ON_ONCE(!(val & NAPIF_STATE_SCHED));
 
 		new = val & ~(NAPIF_STATE_MISSED | NAPIF_STATE_SCHED |
@@ -6078,7 +6076,7 @@  bool napi_complete_done(struct napi_struct *n, int work_done)
 		 */
 		new |= (val & NAPIF_STATE_MISSED) / NAPIF_STATE_MISSED *
 						    NAPIF_STATE_SCHED;
-	} while (cmpxchg(&n->state, val, new) != val);
+	} while (!try_cmpxchg(&n->state, &val, new));
 
 	if (unlikely(val & NAPIF_STATE_MISSED)) {
 		__napi_schedule(n);