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 a4f4d693e2c1287d533c0bc05d9f292f9b529720..edb7d5d9db836959662c508f4fb5426630f36a2d 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 33eb923df8929f5500eab4d085bf61fcc5d7a6a2..8cd2926fb1fe6f9a77fc8943beb5ac2eb3ddd40d 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 aa3539238848562349516fc930985a6898913455..af3c7eecff91d4a49fb1b49cdfce7b7d4c9b11fe 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 c8afd2d4c40b70a245615c08471ac1ae3d6a6fc2..2cba13a532cd82b2a4a53ddf853eced763e7f852 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 245f57dbbb614e818d2f067f1f5c431d7e9f193b..0aae1b2ee931effe8ca3bb05c9952a3d98779f3c 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 };