Commit 1cff3306 authored by Simon Derr's avatar Simon Derr Committed by Eric Van Hensbergen
Browse files

9P/RDMA: count posted buffers without a pending request



In rdma_request():

If an error occurs between posting the recv and the send,
there will be a reply context posted without a pending
request.
Since there is no way to "un-post" it, we remember it and
skip post_recv() for the next request.
Signed-off-by: default avatarSimon Derr <simon.derr@bull.net>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
parent 2f52d07c
......@@ -656,8 +656,10 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
return PTR_ERR(req);
/* if we haven't received a response for oldreq,
remove it from the list. */
/*
* if we haven't received a response for oldreq,
* remove it from the list.
*/
spin_lock(&c->lock);
if (oldreq->status == REQ_STATUS_FLSH)
list_del(&oldreq->req_list);
......
......@@ -74,6 +74,8 @@
* @sq_sem: Semaphore for the SQ
* @rq_depth: The depth of the Receive Queue.
* @rq_sem: Semaphore for the RQ
* @excess_rc : Amount of posted Receive Contexts without a pending request.
* See rdma_request()
* @addr: The remote peer's address
* @req_lock: Protects the active request list
* @cm_done: Completion event for connection management tracking
......@@ -99,6 +101,7 @@ struct p9_trans_rdma {
struct semaphore sq_sem;
int rq_depth;
struct semaphore rq_sem;
atomic_t excess_rc;
struct sockaddr_in addr;
spinlock_t req_lock;
......@@ -426,6 +429,26 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
struct p9_rdma_context *c = NULL;
struct p9_rdma_context *rpl_context = NULL;
/* When an error occurs between posting the recv and the send,
* there will be a receive context posted without a pending request.
* Since there is no way to "un-post" it, we remember it and skip
* post_recv() for the next request.
* So here,
* see if we are this `next request' and need to absorb an excess rc.
* If yes, then drop and free our own, and do not recv_post().
**/
if (unlikely(atomic_read(&rdma->excess_rc) > 0)) {
if ((atomic_sub_return(1, &rdma->excess_rc) >= 0)) {
/* Got one ! */
kfree(req->rc);
req->rc = NULL;
goto dont_need_post_recv;
} else {
/* We raced and lost. */
atomic_inc(&rdma->excess_rc);
}
}
/* Allocate an fcall for the reply */
rpl_context = kmalloc(sizeof *rpl_context, GFP_NOFS);
if (!rpl_context) {
......@@ -451,10 +474,10 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
p9_debug(P9_DEBUG_FCALL, "POST RECV failed\n");
goto recv_error;
}
/* remove posted receive buffer from request structure */
req->rc = NULL;
dont_need_post_recv:
/* Post the request */
c = kmalloc(sizeof *c, GFP_NOFS);
if (!c) {
......@@ -499,6 +522,11 @@ static int rdma_request(struct p9_client *client, struct p9_req_t *req)
send_error:
kfree(c);
p9_debug(P9_DEBUG_ERROR, "Error %d in rdma_request()\n", err);
/* Ach.
* We did recv_post(), but not send. We have one recv_post in excess.
*/
atomic_inc(&rdma->excess_rc);
return err;
/* Handle errors that happened during or while preparing post_recv(): */
......@@ -549,6 +577,7 @@ static struct p9_trans_rdma *alloc_rdma(struct p9_rdma_opts *opts)
init_completion(&rdma->cm_done);
sema_init(&rdma->sq_sem, rdma->sq_depth);
sema_init(&rdma->rq_sem, rdma->rq_depth);
atomic_set(&rdma->excess_rc, 0);
return rdma;
}
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment