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authorLong Li <longli@microsoft.com>2020-03-30 11:04:07 -0700
committerSteve French <stfrench@microsoft.com>2020-04-07 12:41:16 -0500
commit3ffbe78aff93586d3e09e8af4501c563ab367c75 (patch)
treeb6450147a9a1092f6b445dcbde85dba5cba07b9d
parent072a14ec6386829314ca96c725175ac1631360da (diff)
cifs: smbd: Check send queue size before posting a send
Sometimes the remote peer may return more send credits than the send queue depth. If all the send credits are used to post senasd, we may overflow the send queue. Fix this by checking the send queue size before posting a send. Signed-off-by: Long Li <longli@microsoft.com> Signed-off-by: Steve French <stfrench@microsoft.com>
-rw-r--r--fs/cifs/smbdirect.c11
-rw-r--r--fs/cifs/smbdirect.h1
2 files changed, 11 insertions, 1 deletions
diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 79d8dcbd0034..c7ef2d7ce0ef 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -287,6 +287,7 @@ static void send_done(struct ib_cq *cq, struct ib_wc *wc)
if (atomic_dec_and_test(&request->info->send_pending))
wake_up(&request->info->wait_send_pending);
+ wake_up(&request->info->wait_post_send);
mempool_free(request, request->info->request_mempool);
}
@@ -939,7 +940,14 @@ static int smbd_post_send(struct smbd_connection *info,
send_wr.opcode = IB_WR_SEND;
send_wr.send_flags = IB_SEND_SIGNALED;
- atomic_inc(&info->send_pending);
+wait_sq:
+ wait_event(info->wait_post_send,
+ atomic_read(&info->send_pending) < info->send_credit_target);
+ if (unlikely(atomic_inc_return(&info->send_pending) >
+ info->send_credit_target)) {
+ atomic_dec(&info->send_pending);
+ goto wait_sq;
+ }
rc = ib_post_send(info->id->qp, &send_wr, NULL);
if (rc) {
@@ -1733,6 +1741,7 @@ static struct smbd_connection *_smbd_get_connection(
init_waitqueue_head(&info->wait_send_pending);
atomic_set(&info->send_pending, 0);
+ init_waitqueue_head(&info->wait_post_send);
INIT_WORK(&info->disconnect_work, smbd_disconnect_rdma_work);
INIT_WORK(&info->post_send_credits_work, smbd_post_send_credits);
diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h
index f70c7119a456..07c8f5638c39 100644
--- a/fs/cifs/smbdirect.h
+++ b/fs/cifs/smbdirect.h
@@ -114,6 +114,7 @@ struct smbd_connection {
/* Activity accoutning */
atomic_t send_pending;
wait_queue_head_t wait_send_pending;
+ wait_queue_head_t wait_post_send;
/* Receive queue */
struct list_head receive_queue;