[PATCH v2] scsi: target: Save a few cycles in transport_lookup_[cmd|tmr]_lun()

From: Christophe JAILLET
Date: Tue Aug 16 2022 - 00:58:05 EST


Use percpu_ref_tryget_live_rcu() instead of percpu_ref_tryget_live() to
save a few cycles when it is known that the rcu lock is already
taken/released.

Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
Change in v2:
* sync with -next

v1:
* https://lore.kernel.org/all/e4a21bc607c39935cb98d4825cd63ba349820550.1635974637.git.christophe.jaillet@xxxxxxxxxx/
---
drivers/target/target_core_device.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index b7f16ee8aa0e..76c6613a1da7 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -77,7 +77,7 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd)

se_lun = deve->se_lun;

- if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
+ if (!percpu_ref_tryget_live_rcu(&se_lun->lun_ref)) {
se_lun = NULL;
goto out_unlock;
}
@@ -154,7 +154,7 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd)
if (deve) {
se_lun = deve->se_lun;

- if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
+ if (!percpu_ref_tryget_live_rcu(&se_lun->lun_ref)) {
se_lun = NULL;
goto out_unlock;
}
--
2.34.1