random: forget lock in lockless accounting

The only mutable data accessed here is ->entropy_count, but 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>
Signed-off-by: Greg Price <price@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 0 insertions, 4 deletions

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 9675821b4b5a..694510af4fcd 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -970,9 +970,6 @@ 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? */
@@ -995,7 +992,6 @@ retry:
                     < random_write_wakeup_thresh)
                         wakeup_write = 1;
         }
-        spin_unlock_irqrestore(&r->lock, flags);
 
         trace_debit_entropy(r->name, 8 * ibytes);
         if (wakeup_write) {