[PATCH] Reduced stack usage in random.c

Patch from: Matthew Wilcox <willy@debian.org>

Reduces stack use in random.c by 350 (or maybe 700) bytes by sharing a local
array between two functions.

drivers/char/random.c

@@ -1228,10 +1228,8 @@ static ssize_t extract_entropy(struct entropy_store *r, void * buf,
  * at which point we do a "catastrophic reseeding".
  */
 static inline void xfer_secondary_pool(struct entropy_store *r,
-				       size_t nbytes)
+				       size_t nbytes, __u32 *tmp)
 {
-	__u32	tmp[TMP_BUF_SIZE];
-
 	if (r->entropy_count < nbytes * 8 &&
 	    r->entropy_count < r->poolinfo.POOLBITS) {
 		int nwords = min_t(int,
@@ -1284,7 +1282,7 @@ static ssize_t extract_entropy(struct entropy_store *r, void * buf,
 		r->entropy_count = r->poolinfo.POOLBITS;
 
 	if (flags & EXTRACT_ENTROPY_SECONDARY)
-		xfer_secondary_pool(r, nbytes);
+		xfer_secondary_pool(r, nbytes, tmp);
 
 	DEBUG_ENT("%s has %d bits, want %d bits\n",
 		  r == sec_random_state ? "secondary" :