6 files changed, 150 insertions, 1 deletions

diff --git a/drivers/usb/storage/libusual.c b/drivers/usb/storage/libusual.c
index d617e8ae6b0..f970b27ba30 100644
--- a/drivers/usb/storage/libusual.c
+++ b/drivers/usb/storage/libusual.c
@@ -46,6 +46,12 @@ static int usu_probe_thread(void *arg);
 { USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin,bcdDeviceMax), \
   .driver_info = (flags)|(USB_US_TYPE_STOR<<24) }
 
+#define COMPLIANT_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
+                    vendorName, productName, useProtocol, useTransport, \
+                    initFunction, flags) \
+{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax), \
+  .driver_info = (flags) }
+
 #define USUAL_DEV(useProto, useTrans, useType) \
 { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, useProto, useTrans), \
   .driver_info = ((useType)<<24) }
@@ -57,6 +63,7 @@ struct usb_device_id storage_usb_ids [] = {
 
 #undef USUAL_DEV
 #undef UNUSUAL_DEV
+#undef COMPLIANT_DEV
 
 MODULE_DEVICE_TABLE(usb, storage_usb_ids);
 EXPORT_SYMBOL_GPL(storage_usb_ids);
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index e9d6c196a7a..8d78084abf9 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -208,6 +208,14 @@ static int slave_configure(struct scsi_device *sdev)
                  * sector in a larger then 1 sector read, since the performance
                  * impact is negible we set this flag for all USB disks */
                 sdev->last_sector_bug = 1;
+
+                /* Enable last-sector hacks for single-target devices using
+                 * the Bulk-only transport, unless we already know the
+                 * capacity will be decremented or is correct. */
+                if (!(us->fflags & (US_FL_FIX_CAPACITY | US_FL_CAPACITY_OK |
+                                        US_FL_SCM_MULT_TARG)) &&
+                                us->protocol == US_PR_BULK)
+                        us->use_last_sector_hacks = 1;
         } else {
 
                 /* Non-disk-type devices don't need to blacklist any pages
diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index 9cc30afd6d3..1d5438e6363 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -57,6 +57,9 @@
 #include "scsiglue.h"
 #include "debug.h"
 
+#include <linux/blkdev.h>
+#include "../../scsi/sd.h"
+
 
 /***********************************************************************
  * Data transfer routines
@@ -511,6 +514,110 @@ int usb_stor_bulk_transfer_sg(struct us_data* us, unsigned int pipe,
  * Transport routines
  ***********************************************************************/
 
+/* There are so many devices that report the capacity incorrectly,
+ * this routine was written to counteract some of the resulting
+ * problems.
+ */
+static void last_sector_hacks(struct us_data *us, struct scsi_cmnd *srb)
+{
+        struct gendisk *disk;
+        struct scsi_disk *sdkp;
+        u32 sector;
+
+        /* To Report "Medium Error: Record Not Found */
+        static unsigned char record_not_found[18] = {
+                [0]     = 0x70,                 /* current error */
+                [2]     = MEDIUM_ERROR,         /* = 0x03 */
+                [7]     = 0x0a,                 /* additional length */
+                [12]    = 0x14                  /* Record Not Found */
+        };
+
+        /* If last-sector problems can't occur, whether because the
+         * capacity was already decremented or because the device is
+         * known to report the correct capacity, then we don't need
+         * to do anything.
+         */
+        if (!us->use_last_sector_hacks)
+                return;
+
+        /* Was this command a READ(10) or a WRITE(10)? */
+        if (srb->cmnd[0] != READ_10 && srb->cmnd[0] != WRITE_10)
+                goto done;
+
+        /* Did this command access the last sector? */
+        sector = (srb->cmnd[2] << 24) | (srb->cmnd[3] << 16) |
+                        (srb->cmnd[4] << 8) | (srb->cmnd[5]);
+        disk = srb->request->rq_disk;
+        if (!disk)
+                goto done;
+        sdkp = scsi_disk(disk);
+        if (!sdkp)
+                goto done;
+        if (sector + 1 != sdkp->capacity)
+                goto done;
+
+        if (srb->result == SAM_STAT_GOOD && scsi_get_resid(srb) == 0) {
+
+                /* The command succeeded.  If the capacity is odd
+                 * (i.e., if the sector number is even) then the
+                 * "always-even" heuristic would be wrong for this
+                 * device.  Issue a WARN() so that the kerneloops.org
+                 * project will be notified and we will then know to
+                 * mark the device with a CAPACITY_OK flag.  Hopefully
+                 * this will occur for only a few devices.
+                 *
+                 * Use the sign of us->last_sector_hacks to tell whether
+                 * the warning has already been issued; we don't need
+                 * more than one warning per device.
+                 */
+                if (!(sector & 1) && us->use_last_sector_hacks > 0) {
+                        unsigned vid = le16_to_cpu(
+                                        us->pusb_dev->descriptor.idVendor);
+                        unsigned pid = le16_to_cpu(
+                                        us->pusb_dev->descriptor.idProduct);
+                        unsigned rev = le16_to_cpu(
+                                        us->pusb_dev->descriptor.bcdDevice);
+
+                        WARN(1, "%s: Successful last sector success at %u, "
+                                        "device %04x:%04x:%04x\n",
+                                        sdkp->disk->disk_name, sector,
+                                        vid, pid, rev);
+                        us->use_last_sector_hacks = -1;
+                }
+
+        } else {
+                /* The command failed.  Allow up to 3 retries in case this
+                 * is some normal sort of failure.  After that, assume the
+                 * capacity is wrong and we're trying to access the sector
+                 * beyond the end.  Replace the result code and sense data
+                 * with values that will cause the SCSI core to fail the
+                 * command immediately, instead of going into an infinite
+                 * (or even just a very long) retry loop.
+                 */
+                if (++us->last_sector_retries < 3)
+                        return;
+                srb->result = SAM_STAT_CHECK_CONDITION;
+                memcpy(srb->sense_buffer, record_not_found,
+                                sizeof(record_not_found));
+
+                /* In theory we might want to issue a WARN() here if the
+                 * capacity is even, since it could indicate the device
+                 * has the READ CAPACITY bug _and_ the real capacity is
+                 * odd.  But it could also indicate that the device
+                 * simply can't access its last sector, a failure mode
+                 * which is surprisingly common.  So no warning.
+                 */
+        }
+
+ done:
+        /* Don't reset the retry counter for TEST UNIT READY commands,
+         * because they get issued after device resets which might be
+         * caused by a failed last-sector access.
+         */
+        if (srb->cmnd[0] != TEST_UNIT_READY)
+                us->last_sector_retries = 0;
+}
+
 /* Invoke the transport and basic error-handling/recovery methods
  *
  * This is used by the protocol layers to actually send the message to
@@ -544,6 +651,7 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
         /* if the transport provided its own sense data, don't auto-sense */
         if (result == USB_STOR_TRANSPORT_NO_SENSE) {
                 srb->result = SAM_STAT_CHECK_CONDITION;
+                last_sector_hacks(us, srb);
                 return;
         }
 
@@ -705,6 +813,7 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
                         scsi_bufflen(srb) - scsi_get_resid(srb) < srb->underflow)
                 srb->result = (DID_ERROR << 16) | (SUGGEST_RETRY << 24);
 
+        last_sector_hacks(us, srb);
         return;
 
         /* Error and abort processing: try to resynchronize with the device
@@ -732,6 +841,7 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
                 us->transport_reset(us);
         }
         clear_bit(US_FLIDX_RESETTING, &us->dflags);
+        last_sector_hacks(us, srb);
 }
 
 /* Stop the current URB transfer */
diff --git a/drivers/usb/storage/unusual_devs.h b/drivers/usb/storage/unusual_devs.h
index 0330ed53ec1..035bbc5d823 100644
--- a/drivers/usb/storage/unusual_devs.h
+++ b/drivers/usb/storage/unusual_devs.h
@@ -27,7 +27,8 @@
 
 /* IMPORTANT NOTE: This file must be included in another file which does
  * the following thing for it to work:
- * The macro UNUSUAL_DEV() must be defined before this file is included
+ * The UNUSUAL_DEV, COMPLIANT_DEV, and USUAL_DEV macros must be defined
+ * before this file is included.
  */
 
 /* If you edit this file, please try to keep it sorted first by VendorID,
@@ -46,6 +47,12 @@
  * <usb-storage@lists.one-eyed-alien.net>
  */
 
+/* Note: If you add an entry only in order to set the CAPACITY_OK flag,
+ * use the COMPLIANT_DEV macro instead of UNUSUAL_DEV.  This is
+ * because such entries mark devices which actually work correctly,
+ * as opposed to devices that do something strangely or wrongly.
+ */
+
 /* patch submitted by Vivian Bregier <Vivian.Bregier@imag.fr>
  */
 UNUSUAL_DEV(  0x03eb, 0x2002, 0x0100, 0x0100,
@@ -704,6 +711,13 @@ UNUSUAL_DEV(  0x0525, 0xa140, 0x0100, 0x0100,
                 US_SC_8070, US_PR_DEVICE, NULL,
                 US_FL_FIX_INQUIRY ),
 
+/* Added by Alan Stern <stern@rowland.harvard.edu> */
+COMPLIANT_DEV(0x0525, 0xa4a5, 0x0000, 0x9999,
+                "Linux",
+                "File-backed Storage Gadget",
+                US_SC_DEVICE, US_PR_DEVICE, NULL,
+                US_FL_CAPACITY_OK ),
+
 /* Yakumo Mega Image 37
  * Submitted by Stephan Fuhrmann <atomenergie@t-online.de> */
 UNUSUAL_DEV(  0x052b, 0x1801, 0x0100, 0x0100,
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index ce0b580db5e..80e234bf4e5 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -134,6 +134,8 @@ static struct quirks_entry *quirks_list, *quirks_end;
 { USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin,bcdDeviceMax), \
   .driver_info = (flags)|(USB_US_TYPE_STOR<<24) }
 
+#define COMPLIANT_DEV   UNUSUAL_DEV
+
 #define USUAL_DEV(useProto, useTrans, useType) \
 { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, useProto, useTrans), \
   .driver_info = (USB_US_TYPE_STOR<<24) }
@@ -142,6 +144,7 @@ static struct usb_device_id storage_usb_ids [] = {
 
 #       include "unusual_devs.h"
 #undef UNUSUAL_DEV
+#undef COMPLIANT_DEV
 #undef USUAL_DEV
         /* Terminating entry */
         { }
@@ -172,6 +175,8 @@ MODULE_DEVICE_TABLE (usb, storage_usb_ids);
         .initFunction = init_function,  \
 }
 
+#define COMPLIANT_DEV   UNUSUAL_DEV
+
 #define USUAL_DEV(use_protocol, use_transport, use_type) \
 { \
         .useProtocol = use_protocol,    \
@@ -181,6 +186,7 @@ MODULE_DEVICE_TABLE (usb, storage_usb_ids);
 static struct us_unusual_dev us_unusual_dev_list[] = {
 #       include "unusual_devs.h" 
 #       undef UNUSUAL_DEV
+#       undef COMPLIANT_DEV
 #       undef USUAL_DEV
 
         /* Terminating entry */
diff --git a/drivers/usb/storage/usb.h b/drivers/usb/storage/usb.h
index e4674fc715e..65e674e4be9 100644
--- a/drivers/usb/storage/usb.h
+++ b/drivers/usb/storage/usb.h
@@ -154,6 +154,10 @@ struct us_data {
 #ifdef CONFIG_PM
         pm_hook                 suspend_resume_hook;
 #endif
+
+        /* hacks for READ CAPACITY bug handling */
+        int                     use_last_sector_hacks;
+        int                     last_sector_retries;
 };
 
 /* Convert between us_data and the corresponding Scsi_Host */