[PATCH 4/6] cifs: smbd: Don't use RDMA read/write when signing is used

From: Long Li
Date: Mon Apr 16 2018 - 20:51:36 EST


From: Long Li <longli@xxxxxxxxxxxxx>

SMB server will not sign data transferred through RDMA read/write. When
signing is used, it's a good idea to have all the data signed.

In this case, use RDMA send/recv for all data transfers. This will degrade
performance as this is not generally configured in RDMA environemnt. So
warn the user on signing and RDMA send/recv.

Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
---
fs/cifs/cifssmb.c | 3 +++
fs/cifs/smb2ops.c | 18 ++++++++++++++----
fs/cifs/smb2pdu.c | 4 ++--
3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 6d3e40d..1529a08 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -455,6 +455,9 @@ cifs_enable_signing(struct TCP_Server_Info *server, bool mnt_sign_required)
server->sign = true;
}

+ if (cifs_rdma_enabled(server) && server->sign)
+ cifs_dbg(VFS, "Signing is enabled, and RDMA read/write will be disabled");
+
return 0;
}

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 38ebf3f..b76b858 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -252,9 +252,14 @@ smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE;
wsize = min_t(unsigned int, wsize, server->max_write);
#ifdef CONFIG_CIFS_SMB_DIRECT
- if (server->rdma)
- wsize = min_t(unsigned int,
+ if (server->rdma) {
+ if (server->sign)
+ wsize = min_t(unsigned int,
+ wsize, server->smbd_conn->max_fragmented_send_size);
+ else
+ wsize = min_t(unsigned int,
wsize, server->smbd_conn->max_readwrite_size);
+ }
#endif
if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE);
@@ -272,9 +277,14 @@ smb2_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
rsize = volume_info->rsize ? volume_info->rsize : CIFS_DEFAULT_IOSIZE;
rsize = min_t(unsigned int, rsize, server->max_read);
#ifdef CONFIG_CIFS_SMB_DIRECT
- if (server->rdma)
- rsize = min_t(unsigned int,
+ if (server->rdma) {
+ if (server->sign)
+ rsize = min_t(unsigned int,
+ rsize, server->smbd_conn->max_fragmented_recv_size);
+ else
+ rsize = min_t(unsigned int,
rsize, server->smbd_conn->max_readwrite_size);
+ }
#endif

if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index abbefe2..6759035 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2596,7 +2596,7 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
* If we want to do a RDMA write, fill in and append
* smbd_buffer_descriptor_v1 to the end of read request
*/
- if (server->rdma && rdata &&
+ if (server->rdma && rdata && !server->sign &&
rdata->bytes >= server->smbd_conn->rdma_readwrite_threshold) {

struct smbd_buffer_descriptor_v1 *v1;
@@ -2974,7 +2974,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
* If we want to do a server RDMA read, fill in and append
* smbd_buffer_descriptor_v1 to the end of write request
*/
- if (server->rdma && wdata->bytes >=
+ if (server->rdma && !server->sign && wdata->bytes >=
server->smbd_conn->rdma_readwrite_threshold) {

struct smbd_buffer_descriptor_v1 *v1;
--
2.7.4