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nvmf: Capture ns_info onto stack in poll_group_update_subsystem

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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: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/459754
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Seth Howell <seth.howell5141@gmail.com>
This commit is contained in:
Ben Walker 2019-06-28 02:35:05 -07:00 committed by Changpeng Liu
parent ab3abc15aa
commit 85e9760161
1 changed files with 18 additions and 13 deletions
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31
lib/nvmf/nvmf.c
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@ -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;
}
}
}