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dql: annotate data-races around dql->last_obj_cnt

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dql->last_obj_cnt is read/written from different contexts,
without any lock synchronization.

Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20241029191425.2519085-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-10-29 19:14:25 +00:00 committed by Jakub Kicinski
parent 4138e9ec00
commit a911bad094
2 changed files with 2 additions and 2 deletions
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2
include/linux/dynamic_queue_limits.h
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@ -127,7 +127,7 @@ static inline void dql_queued(struct dql *dql, unsigned int count)
if (WARN_ON_ONCE(count > DQL_MAX_OBJECT))
return;
dql->last_obj_cnt = count;
WRITE_ONCE(dql->last_obj_cnt, count);
/* We want to force a write first, so that cpu do not attempt
* to get cache line containing last_obj_cnt, num_queued, adj_limit

2
lib/dynamic_queue_limits.c
View File

@ -179,7 +179,7 @@ void dql_completed(struct dql *dql, unsigned int count)
dql->adj_limit = limit + completed;
dql->prev_ovlimit = ovlimit;
dql->prev_last_obj_cnt = dql->last_obj_cnt;
dql->prev_last_obj_cnt = READ_ONCE(dql->last_obj_cnt);
dql->num_completed = completed;
dql->prev_num_queued = num_queued;