diff options
Diffstat (limited to 'net/9p/trans_rdma.c')
| -rw-r--r-- | net/9p/trans_rdma.c | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c index 926e72d00e5..8f68df5d297 100644 --- a/net/9p/trans_rdma.c +++ b/net/9p/trans_rdma.c @@ -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; } |