random: only update the last_pulled time if we actually transferred entropy

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@mit.edu>
Cc: George Spelvin <linux@horizon.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/char/random.c b/drivers/char/random.c
index bc0de22f31f4..364a8001a2bd 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -920,6 +920,11 @@ 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;
 
@@ -928,10 +933,8 @@ 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)