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Commit 47f2bce9 authored by Roland Dreier's avatar Roland Dreier
Browse files

[IB] srp: don't post receive if no send buf available 



Have __srp_get_tx_iu() fail if the target port's request limit will
not allow the initiator to post a send.  This avoids continuing on and
posting a receive, and then failing to post a corresponding send.  If
that happens, then the initiator will end up with an extra receive
posted, and if this happens to much, the receive queue will overflow.

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 5f068992

drivers/infiniband/ulp/srp/ib_srp.c

+9 −6
Original line number Diff line number Diff line
@@ -802,13 +802,21 @@ static int srp_post_recv(struct srp_target_port *target) 


/*

 * Must be called with target->scsi_host->host_lock held to protect

 * req_lim and tx_head.

 * req_lim and tx_head.  Lock cannot be dropped between call here and

 * call to __srp_post_send().

 */

static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target)

{

	if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)

		return NULL;



	if (unlikely(target->req_lim < 1)) {

		if (printk_ratelimit())

			printk(KERN_DEBUG PFX "Target has req_lim %d\n",

			       target->req_lim);

		return NULL;

	}



	return target->tx_ring[target->tx_head & SRP_SQ_SIZE];

}
@@ -823,11 +831,6 @@ static int __srp_post_send(struct srp_target_port *target, 
	struct ib_send_wr wr, *bad_wr;

	int ret = 0;



	if (target->req_lim < 1) {

		printk(KERN_ERR PFX "Target has req_lim %d\n", target->req_lim);

		return -EAGAIN;

	}



	list.addr   = iu->dma;

	list.length = len;

	list.lkey   = target->srp_host->mr->lkey;