Messages in this thread Patch in this message |  | | Date | Wed, 13 Nov 2013 03:08:28 -0500 | From | Greg Price <> | Subject | [PATCH 7/9] random: forget lock in lockless accounting |
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The only mutable data accessed here is ->entropy_count, but since 902c098a3 ("random: use lockless techniques in the interrupt path") that member isn't protected by the lock anyway. Since 10b3a32d2 ("random: fix accounting race condition") we use cmpxchg to protect our accesses to ->entropy_count here. Drop the use of the lock.
Cc: Jiri Kosina <jkosina@suse.cz> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Price <price@mit.edu> --- drivers/char/random.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c index 5dffca8..1f43f9e 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -974,9 +974,6 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, int entropy_count, orig; size_t ibytes; - /* Hold lock while accounting */ - spin_lock_irqsave(&r->lock, flags); - BUG_ON(r->entropy_count > r->poolinfo->poolfracbits); /* Can we pull enough? */ @@ -999,7 +996,6 @@ retry: < random_write_wakeup_thresh) wakeup_write = 1; } - spin_unlock_irqrestore(&r->lock, flags); trace_debit_entropy(r->name, 8 * ibytes); if (wakeup_write) { -- 1.8.3.2
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