[PATCH AUTOSEL 4.20 65/77] CIFS: Do not assume one credit for async responses

Sasha Levin
2019-02-15T02:36:38Z

From: Pavel Shilovsky <pshilov@microsoft.com>

[ Upstream commit 0fd1d37b0501efc6e295f56ab55cdaff784aa50c ]

If we don't receive a response we can't assume that the server
granted one credit. Assume zero credits in such cases.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cifs/smb2pdu.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index d1ae7cdb236d..3c44c51310c4 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2834,9 +2834,10 @@ smb2_echo_callback(struct mid_q_entry *mid)
{
struct TCP_Server_Info *server = mid->callback_data;
struct smb2_echo_rsp *rsp = (struct smb2_echo_rsp *)mid->resp_buf;
- unsigned int credits_received = 1;
+ unsigned int credits_received = 0;

- if (mid->mid_state == MID_RESPONSE_RECEIVED)
+ if (mid->mid_state == MID_RESPONSE_RECEIVED
+ || mid->mid_state == MID_RESPONSE_MALFORMED)
credits_received = le16_to_cpu(rsp->sync_hdr.CreditRequest);

DeleteMidQEntry(mid);
@@ -3093,7 +3094,7 @@ smb2_readv_callback(struct mid_q_entry *mid)
struct TCP_Server_Info *server = tcon->ses->server;
struct smb2_sync_hdr *shdr =
(struct smb2_sync_hdr *)rdata->iov[0].iov_base;
- unsigned int credits_received = 1;
+ unsigned int credits_received = 0;
struct smb_rqst rqst = { .rq_iov = rdata->iov,
.rq_nvec = 2,
.rq_pages = rdata->pages,
@@ -3132,6 +3133,9 @@ smb2_readv_callback(struct mid_q_entry *mid)
task_io_account_read(rdata->got_bytes);
cifs_stats_bytes_read(tcon, rdata->got_bytes);
break;
+ case MID_RESPONSE_MALFORMED:
+ credits_received = le16_to_cpu(shdr->CreditRequest);
+ /* fall through */
default:
if (rdata->result != -ENODATA)
rdata->result = -EIO;
@@ -3325,7 +3329,7 @@ smb2_writev_callback(struct mid_q_entry *mid)
struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
unsigned int written;
struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)mid->resp_buf;
- unsigned int credits_received = 1;
+ unsigned int credits_received = 0;

switch (mid->mid_state) {
case MID_RESPONSE_RECEIVED:
@@ -3353,6 +3357,9 @@ smb2_writev_callback(struct mid_q_entry *mid)
case MID_RETRY_NEEDED:
wdata->result = -EAGAIN;
break;
+ case MID_RESPONSE_MALFORMED:
+ credits_received = le16_to_cpu(rsp->sync_hdr.CreditRequest);
+ /* fall through */
default:
wdata->result = -EIO;
break;
--
2.19.1