Commit 51ae6d40 authored by Szulik, Maciej's avatar Szulik, Maciej Committed by Tomasz Zawadzki
Browse files

nvme/tcp: add max_completion exit condition to loop inside read_pdu 



A loop inside 'nvme_tcp_qpair_process_completions' makes
'max_completions' actually behaving like a minimum:
	do {
		rc = nvme_tcp_read_pdu(tqpair, &reaped);
		[...]
	} while (reaped < max_completions);

Before this change 'max_completion' constraint, in its true sense,
was actually not respected and a loop inside 'nvme_tcp_read_pdu'
could be executed indefinitely as long as a recv state changed.

To prevent this behavior, max_completion must be passed to
'nvme_tcp_read_pdu' and used as an additional exit condition.

Signed-off-by: default avatarSzulik, Maciej <maciej.szulik@intel.com>
Change-Id: I28da962f4a62f08ddb51915b5d0dae9611a82dee
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/15136


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarAleksey Marchuk <alexeymar@nvidia.com>
parent 49713208

lib/nvme/nvme_tcp.c

+3 −3
Original line number Diff line number Diff line
@@ -1593,7 +1593,7 @@ nvme_tcp_pdu_psh_handle(struct nvme_tcp_qpair *tqpair, uint32_t *reaped) 
}



static int

nvme_tcp_read_pdu(struct nvme_tcp_qpair *tqpair, uint32_t *reaped)

nvme_tcp_read_pdu(struct nvme_tcp_qpair *tqpair, uint32_t *reaped, uint32_t max_completions)

{

	int rc = 0;

	struct nvme_tcp_pdu *pdu;
@@ -1687,7 +1687,7 @@ nvme_tcp_read_pdu(struct nvme_tcp_qpair *tqpair, uint32_t *reaped) 
			assert(0);

			break;

		}

	} while (prev_state != tqpair->recv_state);

	} while (prev_state != tqpair->recv_state && *reaped + tqpair->async_complete < max_completions);



out:

	*reaped += tqpair->async_complete;
@@ -1763,7 +1763,7 @@ nvme_tcp_qpair_process_completions(struct spdk_nvme_qpair *qpair, uint32_t max_c 


	reaped = 0;

	do {

		rc = nvme_tcp_read_pdu(tqpair, &reaped);

		rc = nvme_tcp_read_pdu(tqpair, &reaped, max_completions);

		if (rc < 0) {

			SPDK_DEBUGLOG(nvme, "Error polling CQ! (%d): %s\n",

				      errno, spdk_strerror(errno));