[Patch v3 13/16] CIFS: Pass page offset for encrypting

[Long Li]

From: Long Li <lon...@microsoft.com>

Encryption function needs to read data starting page offset from input
buffer.

This doesn't affect decryption path since it allocates its own page
buffers.

Signed-off-by: Long Li <lon...@microsoft.com>
---
 fs/cifs/smb2ops.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 1fa1c29..38d19b6 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2189,9 +2189,10 @@ init_sg(struct smb_rqst *rqst, u8 *sign)
                smb2_sg_set_buf(&sg[i], rqst->rq_iov[i].iov_base,
                                                rqst->rq_iov[i].iov_len);
        for (j = 0; i < sg_len - 1; i++, j++) {
-               unsigned int len = (j < rqst->rq_npages - 1) ? rqst->rq_pagesz
-                                                       : rqst->rq_tailsz;
-               sg_set_page(&sg[i], rqst->rq_pages[j], len, 0);
+               unsigned int len, offset;
+
+               rqst_page_get_length(rqst, j, &len, &offset);
+               sg_set_page(&sg[i], rqst->rq_pages[j], len, offset);
        }
        smb2_sg_set_buf(&sg[sg_len - 1], sign, SMB2_SIGNATURE_SIZE);
        return sg;
@@ -2332,6 +2333,7 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, 
struct smb_rqst *new_rq,
                return rc;
 
        new_rq->rq_pages = pages;
+       new_rq->rq_offset = old_rq->rq_offset;
        new_rq->rq_npages = old_rq->rq_npages;
        new_rq->rq_pagesz = old_rq->rq_pagesz;
        new_rq->rq_tailsz = old_rq->rq_tailsz;
@@ -2363,10 +2365,14 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, 
struct smb_rqst *new_rq,
 
        /* copy pages form the old */
        for (i = 0; i < npages; i++) {
-               char *dst = kmap(new_rq->rq_pages[i]);
-               char *src = kmap(old_rq->rq_pages[i]);
-               unsigned int len = (i < npages - 1) ? new_rq->rq_pagesz :
-                                                       new_rq->rq_tailsz;
+               char *dst, *src;
+               unsigned int offset, len;
+
+               rqst_page_get_length(new_rq, i, &len, &offset);
+
+               dst = (char *) kmap(new_rq->rq_pages[i]) + offset;
+               src = (char *) kmap(old_rq->rq_pages[i]) + offset;
+
                memcpy(dst, src, len);
                kunmap(new_rq->rq_pages[i]);
                kunmap(old_rq->rq_pages[i]);
-- 
2.7.4