and send no more than credits value requests at once. For SMB/CIFS
it's trivial: increment this value by receiving any message and
decrement by sending one.
Signed-off-by: Pavel Shilovsky <piastry@xxxxxxxxxxx>
---
fs/cifs/cifsglob.h | 24 ++++++++++++++++++++++--
fs/cifs/cifssmb.c | 6 +++---
fs/cifs/connect.c | 17 ++++++-----------
fs/cifs/transport.c | 30 ++++++++++++++++--------------
4 files changed, 47 insertions(+), 30 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 44cfc9a..600d61c 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -255,8 +255,9 @@ struct TCP_Server_Info {
bool noblocksnd; /* use blocking sendmsg */
bool noautotune; /* do not autotune send buf sizes */
bool tcp_nodelay;
+ int credits; /* send no more requests at once */
unsigned int in_flight; /* number of requests on the wire to server */
- spinlock_t req_lock; /* protect the value above */
+ spinlock_t req_lock; /* protect the two values above */
struct mutex srv_mutex;
struct task_struct *tsk;
char server_GUID[16];
@@ -318,14 +319,33 @@ in_flight(struct TCP_Server_Info *server)
return num;
}
+static inline int
+get_credits(struct TCP_Server_Info *server)
+{
+ int num;
+ spin_lock(&server->req_lock);
+ num = server->credits;
+ spin_unlock(&server->req_lock);
+ return num;
+}
+
static inline void
-dec_in_flight(struct TCP_Server_Info *server)
+add_credits(struct TCP_Server_Info *server, unsigned int add)
{
spin_lock(&server->req_lock);
+ server->credits += add;
server->in_flight--;
spin_unlock(&server->req_lock);
}
+static inline void
+set_credits(struct TCP_Server_Info *server, int val)
+{
+ spin_lock(&server->req_lock);
+ server->credits = val;
+ spin_unlock(&server->req_lock);
+}
+
/*
* Macros to allow the TCP_Server_Info->net field and related code to drop out
* when CONFIG_NET_NS isn't set.
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 0b50551..c255c25 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -716,7 +716,7 @@ cifs_echo_callback(struct mid_q_entry *mid)
struct TCP_Server_Info *server = mid->callback_data;
DeleteMidQEntry(mid);
- dec_in_flight(server);
+ add_credits(server, 1);
wake_up(&server->request_q);
}
@@ -1669,7 +1669,7 @@ cifs_readv_callback(struct mid_q_entry *mid)
queue_work(system_nrt_wq, &rdata->work);
DeleteMidQEntry(mid);
- dec_in_flight(server);
+ add_credits(server, 1);
wake_up(&server->request_q);
}
@@ -2110,7 +2110,7 @@ cifs_writev_callback(struct mid_q_entry *mid)
queue_work(system_nrt_wq, &wdata->work);
DeleteMidQEntry(mid);
- dec_in_flight(tcon->ses->server);
+ add_credits(tcon->ses->server, 1);
wake_up(&tcon->ses->server->request_q);
}
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 12286d0..673813f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -642,18 +642,10 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
spin_unlock(&GlobalMid_Lock);
wake_up_all(&server->response_q);
- /*
- * Check if we have blocked requests that need to free. Note that
- * cifs_max_pending is normally 50, but can be set at module install
- * time to as little as two.
- */
+ /* check if we have blocked requests that need to free */
spin_lock(&server->req_lock);
- if (server->in_flight >= cifs_max_pending)
- server->in_flight = cifs_max_pending - 1;
- /*
- * We do not want to set the max_pending too low or we could end up
- * with the counter going negative.
- */
+ if (server->credits <= 0)
+ server->credits = 1;
spin_unlock(&server->req_lock);
/*
* Although there should not be any requests blocked on this queue it
@@ -1910,6 +1902,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
tcp_ses->noautotune = volume_info->noautotune;
tcp_ses->tcp_nodelay = volume_info->sockopt_tcp_nodelay;
tcp_ses->in_flight = 0;
+ tcp_ses->credits = cifs_max_pending;
init_waitqueue_head(&tcp_ses->response_q);
init_waitqueue_head(&tcp_ses->request_q);
INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
@@ -3759,9 +3752,11 @@ int cifs_negotiate_protocol(unsigned int xid, struct cifs_ses *ses)
if (server->maxBuf != 0)
return 0;
+ set_credits(server, cifs_max_pending);
rc = CIFSSMBNegotiate(xid, ses);
if (rc == -EAGAIN) {
/* retry only once on 1st time connection */
+ set_credits(server, cifs_max_pending);
rc = CIFSSMBNegotiate(xid, ses);
if (rc == -EAGAIN)
rc = -EHOSTDOWN;
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index fc1904f..44ac0aa 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -262,16 +262,16 @@ wait_for_free_request(struct TCP_Server_Info *server, const int long_op)
if (long_op == CIFS_ASYNC_OP) {
/* oplock breaks must not be held up */
server->in_flight++;
+ server->credits--;
spin_unlock(&server->req_lock);
return 0;
}
while (1) {
- if (server->in_flight >= cifs_max_pending) {
+ if (server->credits <= 0) {
spin_unlock(&server->req_lock);
cifs_num_waiters_inc(server);
- wait_event(server->request_q,
- in_flight(server) < cifs_max_pending);
+ wait_event(server->request_q, get_credits(server) > 0);
cifs_num_waiters_dec(server);
spin_lock(&server->req_lock);
} else {
@@ -284,8 +284,10 @@ wait_for_free_request(struct TCP_Server_Info *server, const int long_op)
as they are allowed to block on server */
/* update # of requests on the wire to server */
- if (long_op != CIFS_BLOCKING_OP)
+ if (long_op != CIFS_BLOCKING_OP) {
+ server->credits--;
server->in_flight++;
+ }
spin_unlock(&server->req_lock);
break;
}
@@ -360,7 +362,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
mid = AllocMidQEntry(hdr, server);
if (mid == NULL) {
mutex_unlock(&server->srv_mutex);
- dec_in_flight(server);
+ add_credits(server, 1);
wake_up(&server->request_q);
return -ENOMEM;
}
@@ -393,7 +395,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
return rc;
out_err:
delete_mid(mid);
- dec_in_flight(server);
+ add_credits(server, 1);
wake_up(&server->request_q);
return rc;
}
@@ -565,7 +567,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
mutex_unlock(&ses->server->srv_mutex);
cifs_small_buf_release(in_buf);
/* Update # of requests on wire to server */
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
}
@@ -602,7 +604,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
midQ->callback = DeleteMidQEntry;
spin_unlock(&GlobalMid_Lock);
cifs_small_buf_release(in_buf);
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
}
@@ -613,7 +615,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
rc = cifs_sync_mid_result(midQ, ses->server);
if (rc != 0) {
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
}
@@ -638,7 +640,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
midQ->resp_buf = NULL;
out:
delete_mid(midQ);
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
@@ -689,7 +691,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
if (rc) {
mutex_unlock(&ses->server->srv_mutex);
/* Update # of requests on wire to server */
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
}
@@ -722,7 +724,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
/* no longer considered to be "in-flight" */
midQ->callback = DeleteMidQEntry;
spin_unlock(&GlobalMid_Lock);
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
}
@@ -731,7 +733,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
rc = cifs_sync_mid_result(midQ, ses->server);
if (rc != 0) {
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
}
@@ -748,7 +750,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
rc = cifs_check_receive(midQ, ses->server, 0);
out:
delete_mid(midQ);
- dec_in_flight(ses->server);
+ add_credits(ses->server, 1);
wake_up(&ses->server->request_q);
return rc;
--
1.7.1
--
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