[PATCH 3/3] random: only update the last_pulled time if we actually transferred entropy

From: Theodore Ts'o
Date: Tue Jun 10 2014 - 23:30:33 EST


In xfer_secondary_pull(), check to make sure we need to pull from the
secondary pool before checking and potentially updating the
last_pulled time.

Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Cc: George Spelvin <linux@xxxxxxxxxxx>
---
drivers/char/random.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 97f390b..4bb6e37 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -919,6 +919,11 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes);
static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
{
+ if (!r->pull ||
+ r->entropy_count >= (nbytes << (ENTROPY_SHIFT + 3)) ||
+ r->entropy_count > r->poolinfo->poolfracbits)
+ return;
+
if (r->limit == 0 && random_min_urandom_seed) {
unsigned long now = jiffies;

@@ -927,10 +932,8 @@ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
return;
r->last_pulled = now;
}
- if (r->pull &&
- r->entropy_count < (nbytes << (ENTROPY_SHIFT + 3)) &&
- r->entropy_count < r->poolinfo->poolfracbits)
- _xfer_secondary_pool(r, nbytes);
+
+ _xfer_secondary_pool(r, nbytes);
}

static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
--
2.0.0

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