cifs: Allocate encryption header through kmalloc

[ Upstream commit 3946d0d04bb360acca72db5efe9ae8440012d9dc ]

When encryption is used, smb2_transform_hdr is defined on the stack and is
passed to the transport. This doesn't work with RDMA as the buffer needs to
be DMA'ed.

Fix it by using kmalloc.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 0c4df56c825abf30fd8bc9af035010eb32f6f2e0..70412944b267d9a0591c56ae7c1bf89bce02ff6a 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -392,7 +392,7 @@ smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
              struct smb_rqst *rqst, int flags)
 {
        struct kvec iov;
-       struct smb2_transform_hdr tr_hdr;
+       struct smb2_transform_hdr *tr_hdr;
        struct smb_rqst cur_rqst[MAX_COMPOUND];
        int rc;
 
@@ -402,28 +402,34 @@ smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
        if (num_rqst > MAX_COMPOUND - 1)
                return -ENOMEM;
 
-       memset(&cur_rqst[0], 0, sizeof(cur_rqst));
-       memset(&iov, 0, sizeof(iov));
-       memset(&tr_hdr, 0, sizeof(tr_hdr));
-
-       iov.iov_base = &tr_hdr;
-       iov.iov_len = sizeof(tr_hdr);
-       cur_rqst[0].rq_iov = &iov;
-       cur_rqst[0].rq_nvec = 1;
-
        if (!server->ops->init_transform_rq) {
                cifs_dbg(VFS, "Encryption requested but transform callback "
                         "is missing\n");
                return -EIO;
        }
 
+       tr_hdr = kmalloc(sizeof(*tr_hdr), GFP_NOFS);
+       if (!tr_hdr)
+               return -ENOMEM;
+
+       memset(&cur_rqst[0], 0, sizeof(cur_rqst));
+       memset(&iov, 0, sizeof(iov));
+       memset(tr_hdr, 0, sizeof(*tr_hdr));
+
+       iov.iov_base = tr_hdr;
+       iov.iov_len = sizeof(*tr_hdr);
+       cur_rqst[0].rq_iov = &iov;
+       cur_rqst[0].rq_nvec = 1;
+
        rc = server->ops->init_transform_rq(server, num_rqst + 1,
                                            &cur_rqst[0], rqst);
        if (rc)
-               return rc;
+               goto out;
 
        rc = __smb_send_rqst(server, num_rqst + 1, &cur_rqst[0]);
        smb3_free_compound_rqst(num_rqst, &cur_rqst[1]);
+out:
+       kfree(tr_hdr);
        return rc;
 }