[PATCH 4/10] crypto mv_cesa : Fix situations where the src sglist spans more data than the request asks for

[Uri Simchoni <uri@xxxxxxxxxxxx>]

Fix for situations where the source scatterlist spans more data than the
request nbytes

Signed-off-by: Uri Simchoni <uri@xxxxxxxxxxxx>
---
diff -upr linux-2.6.32.8_p3/drivers/crypto/mv_cesa.c 
linux-2.6.32.8_p4/drivers/crypto/mv_cesa.c
--- linux-2.6.32.8_p3/drivers/crypto/mv_cesa.c    2010-03-16 
09:06:10.183753278 +0200
+++ linux-2.6.32.8_p4/drivers/crypto/mv_cesa.c    2010-03-16 
08:40:09.503257114 +0200
@@ -143,27 +143,45 @@ static int mv_setkey_aes(struct crypto_a
     return 0;
 }

-static void setup_data_in(struct ablkcipher_request *req)
+static void copy_src_to_buf(struct req_progress *p, char *dbuf, int len)
 {
     int ret;
-    void *buf;
-
-    if (!cpg->p.sg_src_left) {
-        ret = sg_miter_next(&cpg->p.src_sg_it);
-        BUG_ON(!ret);
-        cpg->p.sg_src_left = cpg->p.src_sg_it.length;
-        cpg->p.src_start = 0;
-    }
+    void *sbuf;
+    int copied = 0;

-    cpg->p.crypt_len = min(cpg->p.sg_src_left, cpg->max_req_size);
+    while (1) {
+        if (!p->sg_src_left) {
+            ret = sg_miter_next(&p->src_sg_it);
+            BUG_ON(!ret);
+            p->sg_src_left = p->src_sg_it.length;
+            p->src_start = 0;
+        }

-    buf = cpg->p.src_sg_it.addr;
-    buf += cpg->p.src_start;
+        sbuf = p->src_sg_it.addr + p->src_start;

-    memcpy(cpg->sram + SRAM_DATA_IN_START, buf, cpg->p.crypt_len);
+        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;
+        }
+    }
+}

-    cpg->p.sg_src_left -= cpg->p.crypt_len;
-    cpg->p.src_start += cpg->p.crypt_len;
+static void setup_data_in(struct ablkcipher_request *req)
+{
+    struct req_progress *p = &cpg->p;
+    p->crypt_len =
+        min((int)req->nbytes - p->total_req_bytes, cpg->max_req_size);
+    copy_src_to_buf(p, cpg->sram + SRAM_DATA_IN_START,
+            p->crypt_len);
 }

 static void mv_process_current_q(int first_block)
@@ -289,12 +307,16 @@ static void dequeue_complete_req(void)
 static int count_sgs(struct scatterlist *sl, unsigned int total_bytes)
 {
     int i = 0;
+    size_t cur_len;

-    do {
-        total_bytes -= sl[i].length;
-        i++;
-
-    } while (total_bytes > 0);
+    while (1) {
+        cur_len = sl[i].length;
+        ++i;
+        if (total_bytes > cur_len)
+            total_bytes -= cur_len;
+        else
+            break;
+    }

     return i;
 }

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