diff mbox series

[net-next,3/4] inetpeer: update inetpeer timestamp in inet_getpeer()

Message ID 20241213130212.1783302-4-edumazet@google.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series inetpeer: reduce false sharing and atomic operations | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
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: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 36 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Dec. 13, 2024, 1:02 p.m. UTC 
inet_putpeer() will be removed in the following patch,
because we will no longer use refcounts.

Update inetpeer timetamp (p->dtime) at lookup time.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/inetpeer.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

Comments

Ido Schimmel Dec. 15, 2024, 3:34 p.m. UTC | #1 
On Fri, Dec 13, 2024 at 01:02:11PM +0000, Eric Dumazet wrote:
> inet_putpeer() will be removed in the following patch,
> because we will no longer use refcounts.
> 
> Update inetpeer timetamp (p->dtime) at lookup time.

Given you're planning a v2: s/timetamp/timestamp/
diff mbox series

Patch

diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 58d2805b046d00cd509e2d2343abfb8eacfbdde7..67827c9bf2c8f3ba842ff1dc3b7e1fc2976e6ef1 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -95,6 +95,7 @@  static struct inet_peer *lookup(const struct inetpeer_addr *daddr,
 {
 	struct rb_node **pp, *parent, *next;
 	struct inet_peer *p;
+	u32 now;
 
 	pp = &base->rb_root.rb_node;
 	parent = NULL;
@@ -110,6 +111,9 @@  static struct inet_peer *lookup(const struct inetpeer_addr *daddr,
 		if (cmp == 0) {
 			if (!refcount_inc_not_zero(&p->refcnt))
 				break;
+			now = jiffies;
+			if (READ_ONCE(p->dtime) != now)
+				WRITE_ONCE(p->dtime, now);
 			return p;
 		}
 		if (gc_stack) {
@@ -150,9 +154,6 @@  static void inet_peer_gc(struct inet_peer_base *base,
 	for (i = 0; i < gc_cnt; i++) {
 		p = gc_stack[i];
 
-		/* The READ_ONCE() pairs with the WRITE_ONCE()
-		 * in inet_putpeer()
-		 */
 		delta = (__u32)jiffies - READ_ONCE(p->dtime);
 
 		if (delta < ttl || !refcount_dec_if_one(&p->refcnt))
@@ -226,11 +227,6 @@  EXPORT_SYMBOL_GPL(inet_getpeer);
 
 void inet_putpeer(struct inet_peer *p)
 {
-	/* The WRITE_ONCE() pairs with itself (we run lockless)
-	 * and the READ_ONCE() in inet_peer_gc()
-	 */
-	WRITE_ONCE(p->dtime, (__u32)jiffies);
-
 	if (refcount_dec_and_test(&p->refcnt))
 		kfree_rcu(p, rcu);
 }