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Commit a58aa4ed authored by Greg Price's avatar Greg Price Committed by Theodore Ts'o
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random: forget lock in lockless accounting 



The only mutable data accessed here is ->entropy_count, but since
10b3a32d ("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>
Signed-off-by: default avatarGreg Price <price@mit.edu>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent ee1de406

drivers/char/random.c

+0 −4
Original line number Original line Diff line number Diff line
@@ -970,9 +970,6 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, 
	int entropy_count, orig;

	int entropy_count, orig;

	size_t ibytes;

	size_t ibytes;





	/* Hold lock while accounting */

	spin_lock_irqsave(&r->lock, flags);



	BUG_ON(r->entropy_count > r->poolinfo->poolfracbits);

	BUG_ON(r->entropy_count > r->poolinfo->poolfracbits);





	/* Can we pull enough? */

	/* Can we pull enough? */
@@ -995,7 +992,6 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min, 
		    < random_write_wakeup_thresh)

		    < random_write_wakeup_thresh)

			wakeup_write = 1;

			wakeup_write = 1;

	}

	}

	spin_unlock_irqrestore(&r->lock, flags);





	trace_debit_entropy(r->name, 8 * ibytes);

	trace_debit_entropy(r->name, 8 * ibytes);

	if (wakeup_write) {

	if (wakeup_write) {