crypto: mv_cesa - refactor copy_src_to_buf()

The main goal was to have it not do anything when a zero len parameter
was being passed (which could lead to a null pointer dereference, as in
this case p->src_sg is null, either). Using the min() macro, the lower
part of the loop gets simpler, too.

Signed-off-by: Phil Sutter <phil.sutter@viprinet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/mv_cesa.c b/drivers/crypto/mv_cesa.c
index fb3f1e3..de09303 100644 (file)
--- a/drivers/crypto/mv_cesa.c
+++ b/drivers/crypto/mv_cesa.c
@@ -187,9 +187,9 @@ static void copy_src_to_buf(struct req_progress *p, char *dbuf, int len)
 {
        int ret;
        void *sbuf;
-       int copied = 0;
+       int copy_len;
 
-       while (1) {
+       while (len) {
                if (!p->sg_src_left) {
                        ret = sg_miter_next(&p->src_sg_it);
                        BUG_ON(!ret);
@@ -199,19 +199,14 @@ static void copy_src_to_buf(struct req_progress *p, char *dbuf, int len)
 
                sbuf = p->src_sg_it.addr + p->src_start;
 
-               if (p->sg_src_left <= len - copied) {
-                       memcpy(dbuf + copied, sbuf, p->sg_src_left);
-                       copied += p->sg_src_left;
-                       p->sg_src_left = 0;
-                       if (copied >= len)
-                               break;
-               } else {
-                       int copy_len = len - copied;
-                       memcpy(dbuf + copied, sbuf, copy_len);
-                       p->src_start += copy_len;
-                       p->sg_src_left -= copy_len;
-                       break;
-               }
+               copy_len = min(p->sg_src_left, len);
+               memcpy(dbuf, sbuf, copy_len);
+
+               p->src_start += copy_len;
+               p->sg_src_left -= copy_len;
+
+               len -= copy_len;
+               dbuf += copy_len;
        }
 }