[PATCH v4 15/40] scsi: core: optimize scsi_evt_emit() by using an atomic iterator

Yury Norov
2024-06-20T17:57:52Z

A plain loop in scsi_evt_thread() opencodes optimized atomic bit traversing
macro. Simplify it by using the dedicated iterator.

CC: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
drivers/scsi/scsi_lib.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index ec39acc986d6..72bebe5247e7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -13,6 +13,7 @@
#include <linux/bitops.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
+#include <linux/find_atomic.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/init.h>
@@ -2588,14 +2589,13 @@ static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
void scsi_evt_thread(struct work_struct *work)
{
struct scsi_device *sdev;
- enum scsi_device_event evt_type;
+ enum scsi_device_event evt_type = SDEV_EVT_FIRST;
LIST_HEAD(event_list);

sdev = container_of(work, struct scsi_device, event_work);

- for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
- if (test_and_clear_bit(evt_type, sdev->pending_events))
- sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
+ for_each_test_and_clear_bit_from(evt_type, sdev->pending_events, SDEV_EVT_LAST + 1)
+ sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);

while (1) {
struct scsi_event *evt;
--
2.43.0