CIFS: Simplify inFlight logic

by making it as unsigned integer and surround access with req_lock
from server structure.

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 24b3dfc..573b899 100644 (file)
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -171,8 +171,7 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
                        seq_printf(m, "TCP status: %d\n\tLocal Users To "
                                   "Server: %d SecMode: 0x%x Req On Wire: %d",
                                   server->tcpStatus, server->srv_count,
-                                  server->sec_mode,
-                                  atomic_read(&server->inFlight));
+                                  server->sec_mode, in_flight(server));
 
 #ifdef CONFIG_CIFS_STATS2
                        seq_printf(m, " In Send: %d In MaxReq Wait: %d",

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d47d20a..fb78bc9 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -250,7 +250,8 @@ struct TCP_Server_Info {
        bool noblocksnd;                /* use blocking sendmsg */
        bool noautotune;                /* do not autotune send buf sizes */
        bool tcp_nodelay;
-       atomic_t inFlight;  /* number of requests on the wire to server */
+       unsigned int in_flight;  /* number of requests on the wire to server */
+       spinlock_t req_lock; /* protect the value above */
        struct mutex srv_mutex;
        struct task_struct *tsk;
        char server_GUID[16];
@@ -303,6 +304,24 @@ struct TCP_Server_Info {
 #endif
 };
 
+static inline unsigned int
+in_flight(struct TCP_Server_Info *server)
+{
+       unsigned int num;
+       spin_lock(&server->req_lock);
+       num = server->in_flight;
+       spin_unlock(&server->req_lock);
+       return num;
+}
+
+static inline void
+dec_in_flight(struct TCP_Server_Info *server)
+{
+       spin_lock(&server->req_lock);
+       server->in_flight--;
+       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 cd66b76..d7cbcfa 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -721,7 +721,7 @@ cifs_echo_callback(struct mid_q_entry *mid)
        struct TCP_Server_Info *server = mid->callback_data;
 
        DeleteMidQEntry(mid);
-       atomic_dec(&server->inFlight);
+       dec_in_flight(server);
        wake_up(&server->request_q);
 }
 
@@ -1674,7 +1674,7 @@ cifs_readv_callback(struct mid_q_entry *mid)
 
        queue_work(system_nrt_wq, &rdata->work);
        DeleteMidQEntry(mid);
-       atomic_dec(&server->inFlight);
+       dec_in_flight(server);
        wake_up(&server->request_q);
 }
 
@@ -2115,7 +2115,7 @@ cifs_writev_callback(struct mid_q_entry *mid)
 
        queue_work(system_nrt_wq, &wdata->work);
        DeleteMidQEntry(mid);
-       atomic_dec(&tcon->ses->server->inFlight);
+       dec_in_flight(tcon->ses->server);
        wake_up(&tcon->ses->server->request_q);
 }
 

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0ac595c..ed91abc 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -643,14 +643,14 @@ static void clean_demultiplex_info(struct TCP_Server_Info *server)
        wake_up_all(&server->response_q);
 
        /* Check if we have blocked requests that need to free. */
-       spin_lock(&GlobalMid_Lock);
-       if (atomic_read(&server->inFlight) >= server->maxReq)
-               atomic_set(&server->inFlight, server->maxReq - 1);
+       spin_lock(&server->req_lock);
+       if (server->in_flight >= server->maxReq)
+               server->in_flight = server->maxReq - 1;
        /*
         * We do not want to set the max_pending too low or we could end up
         * with the counter going negative.
         */
-       spin_unlock(&GlobalMid_Lock);
+       spin_unlock(&server->req_lock);
        /*
         * Although there should not be any requests blocked on this queue it
         * can not hurt to be paranoid and try to wake up requests that may
@@ -1905,7 +1905,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
        tcp_ses->noblocksnd = volume_info->noblocksnd;
        tcp_ses->noautotune = volume_info->noautotune;
        tcp_ses->tcp_nodelay = volume_info->sockopt_tcp_nodelay;
-       atomic_set(&tcp_ses->inFlight, 0);
+       tcp_ses->in_flight = 0;
        tcp_ses->maxReq = 1; /* enough to send negotiate request */
        init_waitqueue_head(&tcp_ses->response_q);
        init_waitqueue_head(&tcp_ses->request_q);

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 99a27cf..e2673aa 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -254,28 +254,29 @@ smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer,
        return smb_sendv(server, &iov, 1);
 }
 
-static int wait_for_free_request(struct TCP_Server_Info *server,
-                                const int long_op)
+static int
+wait_for_free_request(struct TCP_Server_Info *server, const int long_op)
 {
+       spin_lock(&server->req_lock);
+
        if (long_op == CIFS_ASYNC_OP) {
                /* oplock breaks must not be held up */
-               atomic_inc(&server->inFlight);
+               server->in_flight++;
+               spin_unlock(&server->req_lock);
                return 0;
        }
 
-       spin_lock(&GlobalMid_Lock);
        while (1) {
-               if (atomic_read(&server->inFlight) >= server->maxReq) {
-                       spin_unlock(&GlobalMid_Lock);
+               if (server->in_flight >= server->maxReq) {
+                       spin_unlock(&server->req_lock);
                        cifs_num_waiters_inc(server);
                        wait_event(server->request_q,
-                                  atomic_read(&server->inFlight)
-                                    < server->maxReq);
+                                  in_flight(server) < server->maxReq);
                        cifs_num_waiters_dec(server);
-                       spin_lock(&GlobalMid_Lock);
+                       spin_lock(&server->req_lock);
                } else {
                        if (server->tcpStatus == CifsExiting) {
-                               spin_unlock(&GlobalMid_Lock);
+                               spin_unlock(&server->req_lock);
                                return -ENOENT;
                        }
 
@@ -284,8 +285,8 @@ static int wait_for_free_request(struct TCP_Server_Info *server,
 
                        /* update # of requests on the wire to server */
                        if (long_op != CIFS_BLOCKING_OP)
-                               atomic_inc(&server->inFlight);
-                       spin_unlock(&GlobalMid_Lock);
+                               server->in_flight++;
+                       spin_unlock(&server->req_lock);
                        break;
                }
        }
@@ -359,7 +360,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
        mid = AllocMidQEntry(hdr, server);
        if (mid == NULL) {
                mutex_unlock(&server->srv_mutex);
-               atomic_dec(&server->inFlight);
+               dec_in_flight(server);
                wake_up(&server->request_q);
                return -ENOMEM;
        }
@@ -392,7 +393,7 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
        return rc;
 out_err:
        delete_mid(mid);
-       atomic_dec(&server->inFlight);
+       dec_in_flight(server);
        wake_up(&server->request_q);
        return rc;
 }
@@ -564,7 +565,7 @@ 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 */
-               atomic_dec(&ses->server->inFlight);
+               dec_in_flight(ses->server);
                wake_up(&ses->server->request_q);
                return rc;
        }
@@ -601,7 +602,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
                        midQ->callback = DeleteMidQEntry;
                        spin_unlock(&GlobalMid_Lock);
                        cifs_small_buf_release(in_buf);
-                       atomic_dec(&ses->server->inFlight);
+                       dec_in_flight(ses->server);
                        wake_up(&ses->server->request_q);
                        return rc;
                }
@@ -612,7 +613,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 
        rc = cifs_sync_mid_result(midQ, ses->server);
        if (rc != 0) {
-               atomic_dec(&ses->server->inFlight);
+               dec_in_flight(ses->server);
                wake_up(&ses->server->request_q);
                return rc;
        }
@@ -637,7 +638,7 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
                midQ->resp_buf = NULL;
 out:
        delete_mid(midQ);
-       atomic_dec(&ses->server->inFlight);
+       dec_in_flight(ses->server);
        wake_up(&ses->server->request_q);
 
        return rc;
@@ -688,7 +689,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
        if (rc) {
                mutex_unlock(&ses->server->srv_mutex);
                /* Update # of requests on wire to server */
-               atomic_dec(&ses->server->inFlight);
+               dec_in_flight(ses->server);
                wake_up(&ses->server->request_q);
                return rc;
        }
@@ -721,7 +722,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
                        /* no longer considered to be "in-flight" */
                        midQ->callback = DeleteMidQEntry;
                        spin_unlock(&GlobalMid_Lock);
-                       atomic_dec(&ses->server->inFlight);
+                       dec_in_flight(ses->server);
                        wake_up(&ses->server->request_q);
                        return rc;
                }
@@ -730,7 +731,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
 
        rc = cifs_sync_mid_result(midQ, ses->server);
        if (rc != 0) {
-               atomic_dec(&ses->server->inFlight);
+               dec_in_flight(ses->server);
                wake_up(&ses->server->request_q);
                return rc;
        }
@@ -747,7 +748,7 @@ SendReceive(const unsigned int xid, struct cifs_ses *ses,
        rc = cifs_check_receive(midQ, ses->server, 0);
 out:
        delete_mid(midQ);
-       atomic_dec(&ses->server->inFlight);
+       dec_in_flight(ses->server);
        wake_up(&ses->server->request_q);
 
        return rc;