From: Oliver Neukum <oneukum@suse.com>
Date: Mon, 12 Sep 2016 13:19:41 +0000 (+0200)
Subject: scsi: introduce a quirk for false cache reporting
X-Git-Tag: v4.9-rc1~146^2~41
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=050bc4e846af24e77af82d0fa5f718e0919d15a4;p=linux.git

scsi: introduce a quirk for false cache reporting

Some SATA to USB bridges fail to cooperate with some
drives resulting in no cache being present being reported
to the host. That causes the host to skip sending
a command to synchronize caches. That causes data loss
when the drive is powered down.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a4f4d693e2c1..edb7d5d9db83 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -4238,6 +4238,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 				u = IGNORE_UAS (don't bind to the uas driver);
 				w = NO_WP_DETECT (don't test whether the
 					medium is write-protected).
+				y = ALWAYS_SYNC (issue a SYNCHRONIZE_CACHE
+					even if the device claims no cache)
 			Example: quirks=0419:aaf5:rl,0421:0433:rc
 
 	user_debug=	[KNL,ARM]
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 33eb923df892..8cd2926fb1fe 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -296,6 +296,14 @@ static int slave_configure(struct scsi_device *sdev)
 		if (us->fflags & US_FL_BROKEN_FUA)
 			sdev->broken_fua = 1;
 
+		/* Some even totally fail to indicate a cache */
+		if (us->fflags & US_FL_ALWAYS_SYNC) {
+			/* don't read caching information */
+			sdev->skip_ms_page_8 = 1;
+			sdev->skip_ms_page_3f = 1;
+			/* assume sync is needed */
+			sdev->wce_default_on = 1;
+		}
 	} else {
 
 		/*
diff --git a/drivers/usb/storage/unusual_devs.h b/drivers/usb/storage/unusual_devs.h
index aa3539238848..af3c7eecff91 100644
--- a/drivers/usb/storage/unusual_devs.h
+++ b/drivers/usb/storage/unusual_devs.h
@@ -338,6 +338,13 @@ UNUSUAL_DEV(  0x046b, 0xff40, 0x0100, 0x0100,
 		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
 		US_FL_NO_WP_DETECT),
 
+/* Reported by Egbert Eich <eich@suse.com> */
+UNUSUAL_DEV(  0x0480, 0xd010, 0x0100, 0x9999,
+		"Toshiba",
+		"External USB 3.0",
+		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
+		US_FL_ALWAYS_SYNC),
+
 /* Patch submitted by Philipp Friedrich <philipp@void.at> */
 UNUSUAL_DEV(  0x0482, 0x0100, 0x0100, 0x0100,
 		"Kyocera",
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index c8afd2d4c40b..2cba13a532cd 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -498,7 +498,8 @@ void usb_stor_adjust_quirks(struct usb_device *udev, unsigned long *fflags)
 			US_FL_NO_READ_DISC_INFO | US_FL_NO_READ_CAPACITY_16 |
 			US_FL_INITIAL_READ10 | US_FL_WRITE_CACHE |
 			US_FL_NO_ATA_1X | US_FL_NO_REPORT_OPCODES |
-			US_FL_MAX_SECTORS_240 | US_FL_NO_REPORT_LUNS);
+			US_FL_MAX_SECTORS_240 | US_FL_NO_REPORT_LUNS |
+			US_FL_ALWAYS_SYNC);
 
 	p = quirks;
 	while (*p) {
@@ -581,6 +582,9 @@ void usb_stor_adjust_quirks(struct usb_device *udev, unsigned long *fflags)
 		case 'w':
 			f |= US_FL_NO_WP_DETECT;
 			break;
+		case 'y':
+			f |= US_FL_ALWAYS_SYNC;
+			break;
 		/* Ignore unrecognized flag characters */
 		}
 	}
diff --git a/include/linux/usb_usual.h b/include/linux/usb_usual.h
index 245f57dbbb61..0aae1b2ee931 100644
--- a/include/linux/usb_usual.h
+++ b/include/linux/usb_usual.h
@@ -81,6 +81,8 @@
 		/* Sets max_sectors to 240 */			\
 	US_FLAG(NO_REPORT_LUNS,	0x10000000)			\
 		/* Cannot handle REPORT_LUNS */			\
+	US_FLAG(ALWAYS_SYNC, 0x20000000)			\
+		/* lies about caching, so always sync */	\
 
 #define US_FLAG(name, value)	US_FL_##name = value ,
 enum { US_DO_ALL_FLAGS };