Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...

[karo-tx-linux.git] / drivers / char / random.c

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4ad71ef2cd598745d3ca53cba0111edbcebad57d..0a7ac0a7b2520a852be7e61d32702dab391fced0 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -980,7 +980,6 @@ static void push_to_pool(struct work_struct *work)
 static size_t account(struct entropy_store *r, size_t nbytes, int min,
                      int reserved)
 {
-       int have_bytes;
        int entropy_count, orig;
        size_t ibytes;
 
@@ -989,17 +988,19 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
        /* Can we pull enough? */
 retry:
        entropy_count = orig = ACCESS_ONCE(r->entropy_count);
-       have_bytes = entropy_count >> (ENTROPY_SHIFT + 3);
        ibytes = nbytes;
        /* If limited, never pull more than available */
-       if (r->limit)
-               ibytes = min_t(size_t, ibytes, have_bytes - reserved);
+       if (r->limit) {
+               int have_bytes = entropy_count >> (ENTROPY_SHIFT + 3);
+
+               if ((have_bytes -= reserved) < 0)
+                       have_bytes = 0;
+               ibytes = min_t(size_t, ibytes, have_bytes);
+       }
        if (ibytes < min)
                ibytes = 0;
-       if (have_bytes >= ibytes + reserved)
-               entropy_count -= ibytes << (ENTROPY_SHIFT + 3);
-       else
-               entropy_count = reserved << (ENTROPY_SHIFT + 3);
+       if ((entropy_count -= ibytes << (ENTROPY_SHIFT + 3)) < 0)
+               entropy_count = 0;
 
        if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig)
                goto retry;