Commit ec38ec12 authored by Ben Walker's avatar Ben Walker
Browse files

nvmf: Handle wrap-around for global cntlids 



64k sessions over the lifetime of a single target is something
that really could happen, so handle this case.

Change-Id: Iaed92b9ff6cd078fcd7c1efe88cf0c860c77c4ac
Signed-off-by: default avatarBen Walker <benjamin.walker@intel.com>
parent d77c0301

lib/nvmf/session.c

+46 −3
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 
 */



#include <arpa/inet.h>

#include <stdint.h>

#include <string.h>



#include "session.h"
@@ -47,8 +48,6 @@ 


#define MIN_KEEP_ALIVE_TIMEOUT 10000



static uint16_t g_next_cntlid = 1;



static void

nvmf_init_discovery_session_properties(struct spdk_nvmf_session *session)

{
@@ -191,6 +190,44 @@ invalid_connect_response(struct spdk_nvmf_fabric_connect_rsp *rsp, uint8_t iattr 
	rsp->status_code_specific.invalid.ipo = ipo;

}



static uint16_t

spdk_nvmf_session_gen_cntlid(void)

{

	static uint16_t cntlid = 0; /* cntlid is static, so its value is preserved */

	struct spdk_nvmf_subsystem *subsystem;

	uint16_t count;



	count = UINT16_MAX - 1;

	do {

		/* cntlid is an unsigned 16-bit integer, so let it overflow

		 * back to 0 if necessary.

		 */

		cntlid++;

		if (cntlid == 0) {

			/* 0 is not a valid cntlid because it is the reserved value in the RDMA

			 * private data for cntlid. This is the value sent by pre-NVMe-oF 1.1

			 * initiators.

			 */

			cntlid++;

		}



		/* Check if a subsystem with this cntlid currently exists. This could

		 * happen for a very long-lived session on a target with many short-lived

		 * sessions, where cntlid wraps around.

		 */

		subsystem = spdk_nvmf_find_subsystem_with_cntlid(cntlid);



		count--;



	} while (subsystem != NULL && count > 0);



	if (count == 0) {

		return 0;

	}



	return cntlid;

}



void

spdk_nvmf_session_connect(struct spdk_nvmf_conn *conn,

			  struct spdk_nvmf_fabric_connect_cmd *cmd,
@@ -260,7 +297,13 @@ spdk_nvmf_session_connect(struct spdk_nvmf_conn *conn, 


		TAILQ_INIT(&session->connections);



		session->cntlid = g_next_cntlid++;

		session->cntlid = spdk_nvmf_session_gen_cntlid();

		if (session->cntlid == 0) {

			/* Unable to get a cntlid */

			SPDK_ERRLOG("Reached max simultaneous sessions\n");

			rsp->status.sc = SPDK_NVME_SC_INTERNAL_DEVICE_ERROR;

			return;

		}

		session->kato = cmd->kato;

		session->async_event_config.raw = 0;

		session->num_connections = 0;

test/lib/nvmf/session/session_ut.c

+6 −0
Original line number Diff line number Diff line
@@ -44,6 +44,12 @@ SPDK_LOG_REGISTER_TRACE_FLAG("nvmf", SPDK_TRACE_NVMF) 


struct spdk_nvmf_globals g_nvmf_tgt;



struct spdk_nvmf_subsystem *

spdk_nvmf_find_subsystem_with_cntlid(uint16_t cntlid)

{

	return NULL;

}



struct spdk_nvmf_subsystem *

nvmf_find_subsystem(const char *subnqn)

{