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authorTheodore Ts'o <tytso@mit.edu>2013-09-12 14:27:22 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-10-10 14:32:17 -0400
commit3ef4cb2d65ee13d84140cbede8e1980c6ae49ffd (patch)
tree676c6f18c9b75350b92cec558919b6d19a5e5298 /drivers/char
parent5910895f0e868d4f70303922ed00ccdc328b3c30 (diff)
downloadop-kernel-dev-3ef4cb2d65ee13d84140cbede8e1980c6ae49ffd.zip
op-kernel-dev-3ef4cb2d65ee13d84140cbede8e1980c6ae49ffd.tar.gz
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.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 80b5877..89eb5a8 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);
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