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-rw-r--r--fs/cifs/transport.c122
1 files changed, 92 insertions, 30 deletions
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 5be7302853b6..202e0e84efdd 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -387,7 +387,7 @@ smbd_done:
if (rc < 0 && rc != -EINTR)
cifs_dbg(VFS, "Error %d sending data on socket to server\n",
rc);
- else
+ else if (rc > 0)
rc = 0;
return rc;
@@ -783,8 +783,34 @@ cifs_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
}
static void
-cifs_noop_callback(struct mid_q_entry *mid)
+cifs_compound_callback(struct mid_q_entry *mid)
{
+ struct TCP_Server_Info *server = mid->server;
+ unsigned int optype = mid->optype;
+ unsigned int credits_received = 0;
+
+ if (mid->mid_state == MID_RESPONSE_RECEIVED) {
+ if (mid->resp_buf)
+ credits_received = server->ops->get_credits(mid);
+ else
+ cifs_dbg(FYI, "Bad state for cancelled MID\n");
+ }
+
+ add_credits(server, credits_received, optype);
+}
+
+static void
+cifs_compound_last_callback(struct mid_q_entry *mid)
+{
+ cifs_compound_callback(mid);
+ cifs_wake_up_task(mid);
+}
+
+static void
+cifs_cancelled_callback(struct mid_q_entry *mid)
+{
+ cifs_compound_callback(mid);
+ DeleteMidQEntry(mid);
}
int
@@ -795,7 +821,8 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
int i, j, rc = 0;
int timeout, optype;
struct mid_q_entry *midQ[MAX_COMPOUND];
- unsigned int credits = 0;
+ bool cancelled_mid[MAX_COMPOUND] = {false};
+ unsigned int credits[MAX_COMPOUND] = {0};
char *buf;
timeout = flags & CIFS_TIMEOUT_MASK;
@@ -813,13 +840,31 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
return -ENOENT;
/*
- * Ensure that we do not send more than 50 overlapping requests
- * to the same server. We may make this configurable later or
- * use ses->maxReq.
+ * Ensure we obtain 1 credit per request in the compound chain.
+ * It can be optimized further by waiting for all the credits
+ * at once but this can wait long enough if we don't have enough
+ * credits due to some heavy operations in progress or the server
+ * not granting us much, so a fallback to the current approach is
+ * needed anyway.
*/
- rc = wait_for_free_request(ses->server, timeout, optype);
- if (rc)
- return rc;
+ for (i = 0; i < num_rqst; i++) {
+ rc = wait_for_free_request(ses->server, timeout, optype);
+ if (rc) {
+ /*
+ * We haven't sent an SMB packet to the server yet but
+ * we already obtained credits for i requests in the
+ * compound chain - need to return those credits back
+ * for future use. Note that we need to call add_credits
+ * multiple times to match the way we obtained credits
+ * in the first place and to account for in flight
+ * requests correctly.
+ */
+ for (j = 0; j < i; j++)
+ add_credits(ses->server, 1, optype);
+ return rc;
+ }
+ credits[i] = 1;
+ }
/*
* Make sure that we sign in the same order that we send on this socket
@@ -835,18 +880,24 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
for (j = 0; j < i; j++)
cifs_delete_mid(midQ[j]);
mutex_unlock(&ses->server->srv_mutex);
+
/* Update # of requests on wire to server */
- add_credits(ses->server, 1, optype);
+ for (j = 0; j < num_rqst; j++)
+ add_credits(ses->server, credits[j], optype);
return PTR_ERR(midQ[i]);
}
midQ[i]->mid_state = MID_REQUEST_SUBMITTED;
+ midQ[i]->optype = optype;
/*
- * We don't invoke the callback compounds unless it is the last
- * request.
+ * Invoke callback for every part of the compound chain
+ * to calculate credits properly. Wake up this thread only when
+ * the last element is received.
*/
if (i < num_rqst - 1)
- midQ[i]->callback = cifs_noop_callback;
+ midQ[i]->callback = cifs_compound_callback;
+ else
+ midQ[i]->callback = cifs_compound_last_callback;
}
cifs_in_send_inc(ses->server);
rc = smb_send_rqst(ses->server, num_rqst, rqst, flags);
@@ -860,8 +911,20 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
mutex_unlock(&ses->server->srv_mutex);
- if (rc < 0)
+ if (rc < 0) {
+ /* Sending failed for some reason - return credits back */
+ for (i = 0; i < num_rqst; i++)
+ add_credits(ses->server, credits[i], optype);
goto out;
+ }
+
+ /*
+ * At this point the request is passed to the network stack - we assume
+ * that any credits taken from the server structure on the client have
+ * been spent and we can't return them back. Once we receive responses
+ * we will collect credits granted by the server in the mid callbacks
+ * and add those credits to the server structure.
+ */
/*
* Compounding is never used during session establish.
@@ -875,36 +938,34 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
for (i = 0; i < num_rqst; i++) {
rc = wait_for_response(ses->server, midQ[i]);
- if (rc != 0) {
+ if (rc != 0)
+ break;
+ }
+ if (rc != 0) {
+ for (; i < num_rqst; i++) {
cifs_dbg(VFS, "Cancelling wait for mid %llu cmd: %d\n",
midQ[i]->mid, le16_to_cpu(midQ[i]->command));
send_cancel(ses->server, &rqst[i], midQ[i]);
spin_lock(&GlobalMid_Lock);
if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) {
midQ[i]->mid_flags |= MID_WAIT_CANCELLED;
- midQ[i]->callback = DeleteMidQEntry;
- spin_unlock(&GlobalMid_Lock);
- add_credits(ses->server, 1, optype);
- return rc;
+ midQ[i]->callback = cifs_cancelled_callback;
+ cancelled_mid[i] = true;
+ credits[i] = 0;
}
spin_unlock(&GlobalMid_Lock);
}
}
- for (i = 0; i < num_rqst; i++)
- if (midQ[i]->resp_buf)
- credits += ses->server->ops->get_credits(midQ[i]);
- if (!credits)
- credits = 1;
-
for (i = 0; i < num_rqst; i++) {
if (rc < 0)
goto out;
rc = cifs_sync_mid_result(midQ[i], ses->server);
if (rc != 0) {
- add_credits(ses->server, credits, optype);
- return rc;
+ /* mark this mid as cancelled to not free it below */
+ cancelled_mid[i] = true;
+ goto out;
}
if (!midQ[i]->resp_buf ||
@@ -951,9 +1012,10 @@ out:
* This is prevented above by using a noop callback that will not
* wake this thread except for the very last PDU.
*/
- for (i = 0; i < num_rqst; i++)
- cifs_delete_mid(midQ[i]);
- add_credits(ses->server, credits, optype);
+ for (i = 0; i < num_rqst; i++) {
+ if (!cancelled_mid[i])
+ cifs_delete_mid(midQ[i]);
+ }
return rc;
}
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