smb: server: make use of smbdirect_socket.send_io.lcredits.*
This introduces logic to prevent on overflow of
the send submission queue with ib_post_send() easier.
As we first get a local credit and then a remote credit
before we mark us as pending.
From reading the git history of the linux smbdirect
implementations in client and server) it was seen
that a peer granted more credits than we requested.
I guess that only happened because of bugs in our
implementation which was active as client and server.
I guess Windows won't do that.
So the local credits make sure we only use the amount
of credits we asked for.
Fixes: 0626e6641f6b ("cifsd: add server handler for central processing and tranport layers")
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/smb/server/transport_rdma.c b/fs/smb/server/transport_rdma.c
index 2aa8e4d..8aaa950 100644
--- a/fs/smb/server/transport_rdma.c
+++ b/fs/smb/server/transport_rdma.c
@@ -219,6 +219,7 @@ static void smb_direct_disconnect_wake_up_all(struct smbdirect_socket *sc)
* in order to notice the broken connection.
*/
wake_up_all(&sc->status_wait);
+ wake_up_all(&sc->send_io.lcredits.wait_queue);
wake_up_all(&sc->send_io.credits.wait_queue);
wake_up_all(&sc->send_io.pending.zero_wait_queue);
wake_up_all(&sc->recv_io.reassembly.wait_queue);
@@ -916,6 +917,7 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc)
{
struct smbdirect_send_io *sendmsg, *sibling, *next;
struct smbdirect_socket *sc;
+ int lcredits = 0;
sendmsg = container_of(wc->wr_cqe, struct smbdirect_send_io, cqe);
sc = sendmsg->socket;
@@ -930,9 +932,11 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc)
list_for_each_entry_safe(sibling, next, &sendmsg->sibling_list, sibling_list) {
list_del_init(&sibling->sibling_list);
smb_direct_free_sendmsg(sc, sibling);
+ lcredits += 1;
}
/* Note this frees wc->wr_cqe, but not wc */
smb_direct_free_sendmsg(sc, sendmsg);
+ lcredits += 1;
if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {
pr_err("Send error. status='%s (%d)', opcode=%d\n",
@@ -942,6 +946,9 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc)
return;
}
+ atomic_add(lcredits, &sc->send_io.lcredits.count);
+ wake_up(&sc->send_io.lcredits.wait_queue);
+
if (atomic_dec_and_test(&sc->send_io.pending.count))
wake_up(&sc->send_io.pending.zero_wait_queue);
}
@@ -1081,6 +1088,23 @@ static int wait_for_credits(struct smbdirect_socket *sc,
} while (true);
}
+static int wait_for_send_lcredit(struct smbdirect_socket *sc,
+ struct smbdirect_send_batch *send_ctx)
+{
+ if (send_ctx && (atomic_read(&sc->send_io.lcredits.count) <= 1)) {
+ int ret;
+
+ ret = smb_direct_flush_send_list(sc, send_ctx, false);
+ if (ret)
+ return ret;
+ }
+
+ 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,
struct smbdirect_send_batch *send_ctx)
{
@@ -1268,9 +1292,13 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
int data_length;
struct scatterlist sg[SMBDIRECT_SEND_IO_MAX_SGE - 1];
+ ret = wait_for_send_lcredit(sc, send_ctx);
+ if (ret)
+ goto lcredit_failed;
+
ret = wait_for_send_credits(sc, send_ctx);
if (ret)
- return ret;
+ goto credit_failed;
data_length = 0;
for (i = 0; i < niov; i++)
@@ -1278,10 +1306,8 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
ret = smb_direct_create_header(sc, data_length, remaining_data_length,
&msg);
- if (ret) {
- atomic_inc(&sc->send_io.credits.count);
- return ret;
- }
+ if (ret)
+ goto header_failed;
for (i = 0; i < niov; i++) {
struct ib_sge *sge;
@@ -1319,7 +1345,11 @@ static int smb_direct_post_send_data(struct smbdirect_socket *sc,
return 0;
err:
smb_direct_free_sendmsg(sc, msg);
+header_failed:
atomic_inc(&sc->send_io.credits.count);
+credit_failed:
+ atomic_inc(&sc->send_io.lcredits.count);
+lcredit_failed:
return ret;
}
@@ -1897,6 +1927,8 @@ static int smb_direct_init_params(struct smbdirect_socket *sc)
return -EINVAL;
}
+ atomic_set(&sc->send_io.lcredits.count, sp->send_credit_target);
+
maxpages = DIV_ROUND_UP(sp->max_read_write_size, PAGE_SIZE);
sc->rw_io.credits.max = rdma_rw_mr_factor(sc->ib.dev,
sc->rdma.cm_id->port_num,
