Commit 85e97601 authored by Ben Walker's avatar Ben Walker Committed by Changpeng Liu
Browse files

nvmf: Capture ns_info onto stack in poll_group_update_subsystem 



By capturing this pointer onto the stack, we inform the compiler
that we don't expect it to change. That allows the compiler to
generate more efficient code.

Change-Id: I0f3ff9373662198e915269c4498e4902a2cdb808
Signed-off-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/459754


Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
Reviewed-by: default avatarPaul Luse <paul.e.luse@intel.com>
Reviewed-by: default avatarShuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: default avatarSeth Howell <seth.howell5141@gmail.com>
parent ab3abc15

lib/nvmf/nvmf.c

+18 −13
Original line number Diff line number Diff line
@@ -870,6 +870,7 @@ poll_group_update_subsystem(struct spdk_nvmf_poll_group *group, 
	struct spdk_nvmf_ns *ns;

	struct spdk_nvmf_registrant *reg, *tmp;

	struct spdk_io_channel *ch;

	struct spdk_nvmf_subsystem_pg_ns_info *ns_info;



	/* Make sure our poll group has memory for this subsystem allocated */

	if (subsystem->id >= group->num_sgroups) {
@@ -910,9 +911,11 @@ poll_group_update_subsystem(struct spdk_nvmf_poll_group *group, 


		/* Free the extra I/O channels */

		for (i = new_num_ns; i < old_num_ns; i++) {

			if (sgroup->ns_info[i].channel) {

				spdk_put_io_channel(sgroup->ns_info[i].channel);

				sgroup->ns_info[i].channel = NULL;

			ns_info = &sgroup->ns_info[i];



			if (ns_info->channel) {

				spdk_put_io_channel(ns_info->channel);

				ns_info->channel = NULL;

			}

		}
@@ -934,42 +937,44 @@ poll_group_update_subsystem(struct spdk_nvmf_poll_group *group, 
	/* Detect bdevs that were added or removed */

	for (i = 0; i < sgroup->num_ns; i++) {

		ns = subsystem->ns[i];

		ch = sgroup->ns_info[i].channel;

		ns_info = &sgroup->ns_info[i];

		ch = ns_info->channel;



		if (ns == NULL && ch == NULL) {

			/* Both NULL. Leave empty */

		} else if (ns == NULL && ch != NULL) {

			/* There was a channel here, but the namespace is gone. */

			spdk_put_io_channel(ch);

			sgroup->ns_info[i].channel = NULL;

			ns_info->channel = NULL;

		} else if (ns != NULL && ch == NULL) {

			/* A namespace appeared but there is no channel yet */

			sgroup->ns_info[i].channel = spdk_bdev_get_io_channel(ns->desc);

			if (sgroup->ns_info[i].channel == NULL) {

			ch = spdk_bdev_get_io_channel(ns->desc);

			if (ch == NULL) {

				SPDK_ERRLOG("Could not allocate I/O channel.\n");

				return -ENOMEM;

			}

			ns_info->channel = ch;

		} else {

			/* A namespace was present before and didn't change. */

		}



		if (ns == NULL) {

			memset(&sgroup->ns_info[i], 0, sizeof(struct spdk_nvmf_subsystem_pg_ns_info));

			memset(ns_info, 0, sizeof(*ns_info));

		} else {

			sgroup->ns_info[i].crkey = ns->crkey;

			sgroup->ns_info[i].rtype = ns->rtype;

			ns_info->crkey = ns->crkey;

			ns_info->rtype = ns->rtype;

			if (ns->holder) {

				sgroup->ns_info[i].holder_id = ns->holder->hostid;

				ns_info->holder_id = ns->holder->hostid;

			}



			memset(&sgroup->ns_info[i].reg_hostid, 0, SPDK_NVMF_MAX_NUM_REGISTRANTS * sizeof(struct spdk_uuid));

			memset(&ns_info->reg_hostid, 0, SPDK_NVMF_MAX_NUM_REGISTRANTS * sizeof(struct spdk_uuid));

			j = 0;

			TAILQ_FOREACH_SAFE(reg, &ns->registrants, link, tmp) {

				if (j >= SPDK_NVMF_MAX_NUM_REGISTRANTS) {

					SPDK_ERRLOG("Maximum %u registrants can support.\n", SPDK_NVMF_MAX_NUM_REGISTRANTS);

					return -EINVAL;

				}

				sgroup->ns_info[i].reg_hostid[j++] = reg->hostid;

				ns_info->reg_hostid[j++] = reg->hostid;

			}

		}

	}