linux-kernel - [PATCH] Revert "usb: storage: Add quirk for Samsung Fit flash"

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Date:   Tue, 13 Sep 2022 19:37:12 +0900
From:   sunghwan jung <onenowy@...il.com>
To:     stern@...land.harvard.edu
Cc:     gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
        usb-storage@...ts.one-eyed-alien.net, linux-kernel@...r.kernel.org,
        sunghwan jung <onenowy@...il.com>
Subject: [PATCH] Revert "usb: storage: Add quirk for Samsung Fit flash"

This reverts commit 86d92f5465958752481269348d474414dccb1552, which fix the timeout issue for "Samsung Fit Flash".

But the commit affects not only "Samsung Fit Flash" but also other usb storages that use the same controller and causes severe performance regression.

 # hdparm -t /dev/sda (without the quirk)
 Timing buffered disk reads: 622 MB in  3.01 seconds = 206.66 MB/sec

 # hdparm -t /dev/sda (with the quirk)
 Timing buffered disk reads: 220 MB in  3.00 seconds =  73.32 MB/sec

The commit author mentioned that "Issue was reproduced after device has bad block", so this quirk should be applied when we have the timeout issue with a device that has bad blocks.

We revert the commit so that we apply this quirk by adding kernel paramters using a bootloader or other ways when we really need it, without the performance regression with devices that don't have the issue.
---
 drivers/usb/storage/unusual_devs.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/usb/storage/unusual_devs.h b/drivers/usb/storage/unusual_devs.h
index 4993227ab293..20dcbccb290b 100644
--- a/drivers/usb/storage/unusual_devs.h
+++ b/drivers/usb/storage/unusual_devs.h
@@ -1275,12 +1275,6 @@ UNUSUAL_DEV( 0x090a, 0x1200, 0x0000, 0x9999,
 		USB_SC_RBC, USB_PR_BULK, NULL,
 		0 ),
 
-UNUSUAL_DEV(0x090c, 0x1000, 0x1100, 0x1100,
-		"Samsung",
-		"Flash Drive FIT",
-		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
-		US_FL_MAX_SECTORS_64),
-
 /* aeb */
 UNUSUAL_DEV( 0x090c, 0x1132, 0x0000, 0xffff,
 		"Feiya",
-- 
2.37.3