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author | Theodore Ts'o <tytso@mit.edu> | 2013-09-12 20:27:22 +0200 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2013-10-10 20:32:17 +0200 |
commit | 3ef4cb2d65ee13d84140cbede8e1980c6ae49ffd (patch) | |
tree | 676c6f18c9b75350b92cec558919b6d19a5e5298 /drivers/char | |
parent | random: fix the tracepoint for get_random_bytes(_arch) (diff) | |
download | linux-3ef4cb2d65ee13d84140cbede8e1980c6ae49ffd.tar.xz linux-3ef4cb2d65ee13d84140cbede8e1980c6ae49ffd.zip |
random: optimize spinlock use in add_device_randomness()
The add_device_randomness() function calls mix_pool_bytes() twice for
the input pool and the non-blocking pool, for a total of four times.
By using _mix_pool_byte() and taking the spinlock in
add_device_randomness(), we can halve the number of times we need
take each pool's spinlock.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'drivers/char')
-rw-r--r-- | drivers/char/random.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 80b58774e891..89eb5a8dec82 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -710,12 +710,18 @@ struct timer_rand_state { void add_device_randomness(const void *buf, unsigned int size) { unsigned long time = random_get_entropy() ^ jiffies; + unsigned long flags; trace_add_device_randomness(size, _RET_IP_); - mix_pool_bytes(&input_pool, buf, size, NULL); - mix_pool_bytes(&input_pool, &time, sizeof(time), NULL); - mix_pool_bytes(&nonblocking_pool, buf, size, NULL); - mix_pool_bytes(&nonblocking_pool, &time, sizeof(time), NULL); + spin_lock_irqsave(&input_pool.lock, flags); + _mix_pool_bytes(&input_pool, buf, size, NULL); + _mix_pool_bytes(&input_pool, &time, sizeof(time), NULL); + spin_unlock_irqrestore(&input_pool.lock, flags); + + spin_lock_irqsave(&nonblocking_pool.lock, flags); + _mix_pool_bytes(&nonblocking_pool, buf, size, NULL); + _mix_pool_bytes(&nonblocking_pool, &time, sizeof(time), NULL); + spin_unlock_irqrestore(&nonblocking_pool.lock, flags); } EXPORT_SYMBOL(add_device_randomness); |