uas: Add US_FL_MAX_SECTORS_240 flag

The usb-storage driver sets max_sectors = 240 in its scsi-host template,
for uas we do not want to do that for all devices, but testing has shown
that some devices need it.

This commit adds a US_FL_MAX_SECTORS_240 flag for such devices, and
implements support for it in uas.c, while at it it also adds support
for US_FL_MAX_SECTORS_64 to uas.c.

Cc: stable@vger.kernel.org # 3.16
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 18 insertions, 2 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f6befa9855c1..61ab1628a057 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3787,6 +3787,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                                         READ_CAPACITY_16 command);
                                 f = NO_REPORT_OPCODES (don't use report opcodes
                                         command, uas only);
+                                g = MAX_SECTORS_240 (don't transfer more than
+                                        240 sectors at a time, uas only);
                                 h = CAPACITY_HEURISTICS (decrease the
                                         reported device capacity by one
                                         sector if the number is odd);
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index c6109c111aab..6d3122afeed3 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -759,7 +759,10 @@ static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
 
 static int uas_slave_alloc(struct scsi_device *sdev)
 {
-        sdev->hostdata = (void *)sdev->host->hostdata;
+        struct uas_dev_info *devinfo =
+                (struct uas_dev_info *)sdev->host->hostdata;
+
+        sdev->hostdata = devinfo;
 
         /* USB has unusual DMA-alignment requirements: Although the
          * starting address of each scatter-gather element doesn't matter,
@@ -778,6 +781,11 @@ static int uas_slave_alloc(struct scsi_device *sdev)
          */
         blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
 
+        if (devinfo->flags & US_FL_MAX_SECTORS_64)
+                blk_queue_max_hw_sectors(sdev->request_queue, 64);
+        else if (devinfo->flags & US_FL_MAX_SECTORS_240)
+                blk_queue_max_hw_sectors(sdev->request_queue, 240);
+
         return 0;
 }
 
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index db6f6b5ec745..6c10c888f35f 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -479,7 +479,8 @@ void usb_stor_adjust_quirks(struct usb_device *udev, unsigned long *fflags)
                         US_FL_SINGLE_LUN | US_FL_NO_WP_DETECT |
                         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_NO_ATA_1X | US_FL_NO_REPORT_OPCODES |
+                        US_FL_MAX_SECTORS_240);
 
         p = quirks;
         while (*p) {
@@ -520,6 +521,9 @@ void usb_stor_adjust_quirks(struct usb_device *udev, unsigned long *fflags)
                 case 'f':
                         f |= US_FL_NO_REPORT_OPCODES;
                         break;
+                case 'g':
+                        f |= US_FL_MAX_SECTORS_240;
+                        break;
                 case 'h':
                         f |= US_FL_CAPACITY_HEURISTICS;
                         break;
diff --git a/include/linux/usb_usual.h b/include/linux/usb_usual.h
index a7f2604c5f25..7f5f78bd15ad 100644
--- a/include/linux/usb_usual.h
+++ b/include/linux/usb_usual.h
@@ -77,6 +77,8 @@
                 /* Cannot handle ATA_12 or ATA_16 CDBs */       \
         US_FLAG(NO_REPORT_OPCODES,      0x04000000)             \
                 /* Cannot handle MI_REPORT_SUPPORTED_OPERATION_CODES */ \
+        US_FLAG(MAX_SECTORS_240,        0x08000000)             \
+                /* Sets max_sectors to 240 */                   \
 
 #define US_FLAG(name, value)    US_FL_##name = value ,
 enum { US_DO_ALL_FLAGS };