[PATCH] cifs: Fix kmap_local_page() unmapping

[Ira Weiny <ira.weiny@intel.com>]

kmap_local_page() requires kunmap_local() to unmap the mapping.  In
addition memcpy_page() is provided to perform this common memcpy
pattern.

Replace the kmap_local_page() and broken kunmap() with memcpy_page()

Fixes: d406d26745ab ("cifs: skip alloc when request has no pages")
Cc: Paulo Alcantara <pc@cjr.nz>
Cc: Steve French <sfrench@samba.org>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
---
 fs/cifs/smb2ops.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index dc160de7a6de..0d7e9bcd9f34 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4488,17 +4488,12 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst,
 
 		/* copy pages form the old */
 		for (j = 0; j < npages; j++) {
-			char *dst, *src;
 			unsigned int offset, len;
 
 			rqst_page_get_length(new, j, &len, &offset);
 
-			dst = kmap_local_page(new->rq_pages[j]) + offset;
-			src = kmap_local_page(old->rq_pages[j]) + offset;
-
-			memcpy(dst, src, len);
-			kunmap(new->rq_pages[j]);
-			kunmap(old->rq_pages[j]);
+			memcpy_page(new->rq_pages[j], offset,
+				    old->rq_pages[j], offset, len);
 		}
 	}
 

---
base-commit: 1b929c02afd37871d5afb9d498426f83432e71c2
change-id: 20221229-cifs-kmap-6700dabafcdf

Best regards,
-- 
Ira Weiny <ira.weiny@intel.com>