linux-kernel - [PATCH v4 15/40] scsi: core: optimize scsi_evt

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Message-ID: <20240620175703.605111-16-yury.norov@gmail.com>
Date: Thu, 20 Jun 2024 10:56:38 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Sathya Prakash Veerichetty <sathya.prakash@...adcom.com>,
	Kashyap Desai <kashyap.desai@...adcom.com>,
	Sumit Saxena <sumit.saxena@...adcom.com>,
	Sreekanth Reddy <sreekanth.reddy@...adcom.com>,
	"James E.J. Bottomley" <jejb@...ux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Nilesh Javali <njavali@...vell.com>,
	Manish Rangankar <mrangankar@...vell.com>,
	GR-QLogic-Storage-Upstream@...vell.com,
	mpi3mr-linuxdrv.pdl@...adcom.com,
	linux-scsi@...r.kernel.org
Cc: Yury Norov <yury.norov@...il.com>,
	Alexey Klimov <alexey.klimov@...aro.org>,
	Bart Van Assche <bvanassche@....org>,
	Jan Kara <jack@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Wilcox <willy@...radead.org>,
	Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Sergey Shtylyov <s.shtylyov@....ru>
Subject: [PATCH v4 15/40] scsi: core: optimize scsi_evt_emit() by using an atomic iterator

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@....org>
Signed-off-by: Yury Norov <yury.norov@...il.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