smb: client: port and use the wait_for_credits logic used by server

This simplifies the logic and prepares the use of
smbdirect_send_batch in order to make sure
all messages in a multi fragment send are grouped
together.

We'll add the smbdirect_send_batch processin
in a later patch.

Cc: <stable@vger.kernel.org> # 6.18.x
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Long Li <longli@microsoft.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c
index cfbe8ce0db42201dbc13e00839063033d736a2c8..405931ce3978f483b90707eeaf6afc925f1a99cd 100644 (file)
--- a/fs/smb/client/smbdirect.c
+++ b/fs/smb/client/smbdirect.c
@@ -1137,6 +1137,44 @@ static int smbd_post_send(struct smbdirect_socket *sc,
        return rc;
 }
 
+static int wait_for_credits(struct smbdirect_socket *sc,
+                           wait_queue_head_t *waitq, atomic_t *total_credits,
+                           int needed)
+{
+       int ret;
+
+       do {
+               if (atomic_sub_return(needed, total_credits) >= 0)
+                       return 0;
+
+               atomic_add(needed, total_credits);
+               ret = wait_event_interruptible(*waitq,
+                                              atomic_read(total_credits) >= needed ||
+                                              sc->status != SMBDIRECT_SOCKET_CONNECTED);
+
+               if (sc->status != SMBDIRECT_SOCKET_CONNECTED)
+                       return -ENOTCONN;
+               else if (ret < 0)
+                       return ret;
+       } while (true);
+}
+
+static int wait_for_send_lcredit(struct smbdirect_socket *sc)
+{
+       return wait_for_credits(sc,
+                               &sc->send_io.lcredits.wait_queue,
+                               &sc->send_io.lcredits.count,
+                               1);
+}
+
+static int wait_for_send_credits(struct smbdirect_socket *sc)
+{
+       return wait_for_credits(sc,
+                               &sc->send_io.credits.wait_queue,
+                               &sc->send_io.credits.count,
+                               1);
+}
+
 static int smbd_post_send_iter(struct smbdirect_socket *sc,
                               struct iov_iter *iter,
                               int *_remaining_data_length)
@@ -1149,41 +1187,19 @@ static int smbd_post_send_iter(struct smbdirect_socket *sc,
        struct smbdirect_data_transfer *packet;
        int new_credits = 0;
 
-wait_lcredit:
-       /* Wait for local send credits */
-       rc = wait_event_interruptible(sc->send_io.lcredits.wait_queue,
-               atomic_read(&sc->send_io.lcredits.count) > 0 ||
-               sc->status != SMBDIRECT_SOCKET_CONNECTED);
-       if (rc)
-               goto err_wait_lcredit;
-
-       if (sc->status != SMBDIRECT_SOCKET_CONNECTED) {
-               log_outgoing(ERR, "disconnected not sending on wait_credit\n");
+       rc = wait_for_send_lcredit(sc);
+       if (rc) {
+               log_outgoing(ERR, "disconnected not sending on wait_lcredit\n");
                rc = -EAGAIN;
                goto err_wait_lcredit;
        }
-       if (unlikely(atomic_dec_return(&sc->send_io.lcredits.count) < 0)) {
-               atomic_inc(&sc->send_io.lcredits.count);
-               goto wait_lcredit;
-       }
 
-wait_credit:
-       /* Wait for send credits. A SMBD packet needs one credit */
-       rc = wait_event_interruptible(sc->send_io.credits.wait_queue,
-               atomic_read(&sc->send_io.credits.count) > 0 ||
-               sc->status != SMBDIRECT_SOCKET_CONNECTED);
-       if (rc)
-               goto err_wait_credit;
-
-       if (sc->status != SMBDIRECT_SOCKET_CONNECTED) {
+       rc = wait_for_send_credits(sc);
+       if (rc) {
                log_outgoing(ERR, "disconnected not sending on wait_credit\n");
                rc = -EAGAIN;
                goto err_wait_credit;
        }
-       if (unlikely(atomic_dec_return(&sc->send_io.credits.count) < 0)) {
-               atomic_inc(&sc->send_io.credits.count);
-               goto wait_credit;
-       }
 
        request = mempool_alloc(sc->send_io.mem.pool, GFP_KERNEL);
        if (!request) {