5/10
----------------------------
commit 66329cffcdf3124b6b391e20b39568a2c031bd77
Author: Jaren Johnston <jaren's email>
Date: Fri Jun 8 15:48:57 2012 -0700
handle null IO buffers gracefully
Change-Id: I9039b49d719318e82dd30845029081b162c759e9
diff --git a/zc.c b/zc.c
index ce929f0..96a011d 100644
--- a/zc.c
+++ b/zc.c
@@ -135,71 +135,86 @@ int get_userbuf(struct csession *ses,
struct scatterlist **src_sg,
struct scatterlist **dst_sg)
{
- int src_pagecount, dst_pagecount = 0, pagecount, write_src =
1;
+ int src_pagecount, dst_pagecount;
int rc;
- if (src == NULL)
- return -EINVAL;
+ /* Empty input is a valid option to many algorithms & is
tested by NIST/FIPS */
+ /* Make sure NULL input has 0 length */
+ if (!src && src_len) { src_len = 0; }
+
+ /* I don't know that null output is ever useful, but we can
handle it gracefully */
+ /* Make sure NULL output has 0 length */
+ if (!dst && dst_len) { dst_len = 0; }
if (ses->alignmask && !IS_ALIGNED((unsigned long)src,
ses->alignmask)) {
dprintk(2, KERN_WARNING, "%s: careful -
source address %lx is not %d byte aligned\n",
__func__,
(unsigned long)src, ses->alignmask + 1);
}
- if (src == dst) {
- /* dst == src */
- src_len = max(src_len, dst_len);
- dst_len = src_len;
- }
+ if (ses->alignmask && !IS_ALIGNED((unsigned long)dst,
ses->alignmask)) {
+ dprintk(2, KERN_WARNING, "%s: careful -
destination address %lx is not %d byte aligned\n",
+ __func__,
(unsigned long)dst, ses->alignmask + 1);
+ }
src_pagecount = PAGECOUNT(src, src_len);
- if (!ses->cdata.init) { /* hashing only
*/
- write_src = 0;
- } else if (src != dst) { /* non-in-situ transformation
*/
- if (dst == NULL)
- return -EINVAL;
+ dst_pagecount = PAGECOUNT(dst, dst_len);
- dst_pagecount = PAGECOUNT(dst, dst_len);
- write_src = 0;
+ ses->used_pages = (src == dst) ? max(src_pagecount,
dst_pagecount)
+ : src_pagecount +
dst_pagecount;
- if (ses->alignmask && !IS_ALIGNED((unsigned
long)dst, ses->alignmask)) {
- dprintk(2, KERN_WARNING, "%s:
careful - destination address %lx is not %d byte aligned\n",
-
__func__, (unsigned long)dst, ses->alignmask + 1);
- }
- }
- ses->used_pages = pagecount = src_pagecount + dst_pagecount;
+ ses->readonly_pages = (src == dst) ? 0 : src_pagecount;
- if (write_src) ses->readonly_pages = 0;
- else ses->readonly_pages = src_pagecount;
-
- if (pagecount > ses->array_size) {
- rc = adjust_sg_array(ses, pagecount);
+ if (ses->used_pages > ses->array_size) {
+ rc = adjust_sg_array(ses, ses->used_pages);
if (rc)
return rc;
}
- rc = __get_userbuf(src, src_len, write_src, src_pagecount,
- ses->pages, ses->sg, task, mm);
- if (unlikely(rc)) {
- dprintk(1, KERN_ERR,
- "failed to get user pages for
data input\n");
- return -EINVAL;
+ if (src == dst) {
+ rc = __get_userbuf(src, src_len, 1,
ses->used_pages,
+ ses->pages,
ses->sg, task, mm);
+ if (unlikely(rc)) {
+ dprintk(1, KERN_ERR,
+ "failed to
get user pages for data IO\n");
+ return rc;
+ }
+ (*src_sg) = (*dst_sg) = ses->sg;
}
- (*src_sg) = (*dst_sg) = ses->sg;
-
- if (!dst_pagecount)
- return 0;
-
- (*dst_sg) = ses->sg + src_pagecount;
-
- rc = __get_userbuf(dst, dst_len, 1, dst_pagecount,
- ses->pages + src_pagecount, *dst_sg,
- task, mm);
- if (unlikely(rc)) {
- dprintk(1, KERN_ERR,
- "failed to get user pages for data
output\n");
- release_user_pages(ses);
- return -EINVAL;
+ else {
+ const unsigned int readonly_pages =
ses->readonly_pages;
+ const unsigned int writable_pages =
ses->used_pages - readonly_pages;
+
+ if(likely(src)) {
+ rc = __get_userbuf(src,
src_len, 0, readonly_pages,
+
ses->pages, ses->sg, task, mm);
+ if (unlikely(rc)) {
+ dprintk(1,
KERN_ERR,
+
"failed to get user pages for data input\n");
+ return rc;
+ }
+ *src_sg = ses->sg;
+ }
+ else {
+ *src_sg = NULL; // no input
+ }
+
+ if(likely(dst)) {
+ struct page **dst_pages =
ses->pages + readonly_pages;
+ *dst_sg = ses->sg +
readonly_pages;
+
+ rc = __get_userbuf(dst,
dst_len, 1, writable_pages,
+
dst_pages, *dst_sg, task, mm);
+ if (unlikely(rc)) {
+ dprintk(1,
KERN_ERR,
+
"failed to get user pages for data output\n");
+
release_user_pages(ses); /* FIXME: use __release_userbuf(src, ...) */
+ return rc;
+ }
+ }
+ else {
+ *dst_sg = NULL; // ignore
output
+ }
}
return 0;
}
+
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