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 a4f4d69..edb7d5d 100644 (file)
--- 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 33eb923..8cd2926 100644 (file)
--- 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 aa35392..af3c7ee 100644 (file)
--- 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 c8afd2d..2cba13a 100644 (file)
--- 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 245f57d..0aae1b2 100644 (file)
--- 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 };