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>

1 files changed, 10 insertions, 15 deletions

diff --git a/drivers/crypto/mv_cesa.c b/drivers/crypto/mv_cesa.c
index fb3f1e35623d..de09303675d8 100644
--- 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;
         }
 }