5 files changed, 46 insertions, 33 deletions

diff --git a/drivers/usb/storage/Makefile b/drivers/usb/storage/Makefile
index c5126a4cd954..a67ddcbb4e24 100644
--- a/drivers/usb/storage/Makefile
+++ b/drivers/usb/storage/Makefile
@@ -6,7 +6,7 @@
 # Rewritten to use lists instead of if-statements.
 #
 
-ccflags-y := -Idrivers/scsi
+ccflags-y := -I $(srctree)/drivers/scsi
 
 obj-$(CONFIG_USB_UAS)		+= uas.o
 obj-$(CONFIG_USB_STORAGE)	+= usb-storage.o
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index a73ea495d5a7..30790240aec6 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -65,6 +65,7 @@ static const char* host_info(struct Scsi_Host *host)
 static int slave_alloc (struct scsi_device *sdev)
 {
 	struct us_data *us = host_to_us(sdev->host);
+	int maxp;
 
 	/*
 	 * Set the INQUIRY transfer length to 36.  We don't use any of
@@ -74,20 +75,17 @@ static int slave_alloc (struct scsi_device *sdev)
 	sdev->inquiry_len = 36;
 
 	/*
-	 * USB has unusual DMA-alignment requirements: Although the
-	 * starting address of each scatter-gather element doesn't matter,
-	 * the length of each element except the last must be divisible
-	 * by the Bulk maxpacket value.  There's currently no way to
-	 * express this by block-layer constraints, so we'll cop out
-	 * and simply require addresses to be aligned at 512-byte
-	 * boundaries.  This is okay since most block I/O involves
-	 * hardware sectors that are multiples of 512 bytes in length,
-	 * and since host controllers up through USB 2.0 have maxpacket
-	 * values no larger than 512.
-	 *
-	 * But it doesn't suffice for Wireless USB, where Bulk maxpacket
-	 * values can be as large as 2048.  To make that work properly
-	 * will require changes to the block layer.
+	 * USB has unusual scatter-gather requirements: the length of each
+	 * scatterlist element except the last must be divisible by the
+	 * Bulk maxpacket value.  Fortunately this value is always a
+	 * power of 2.  Inform the block layer about this requirement.
+	 */
+	maxp = usb_maxpacket(us->pusb_dev, us->recv_bulk_pipe, 0);
+	blk_queue_virt_boundary(sdev->request_queue, maxp - 1);
+
+	/*
+	 * Some host controllers may have alignment requirements.
+	 * We'll play it safe by requiring 512-byte alignment always.
 	 */
 	blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
 
@@ -197,8 +195,11 @@ static int slave_configure(struct scsi_device *sdev)
 		 */
 		sdev->skip_ms_page_8 = 1;
 
-		/* Some devices don't handle VPD pages correctly */
-		sdev->skip_vpd_pages = 1;
+		/*
+		 * Some devices don't handle VPD pages correctly, so skip vpd
+		 * pages if not forced by SCSI layer.
+		 */
+		sdev->skip_vpd_pages = !sdev->try_vpd_pages;
 
 		/* Do not attempt to use REPORT SUPPORTED OPERATION CODES */
 		sdev->no_report_opcodes = 1;
diff --git a/drivers/usb/storage/sierra_ms.c b/drivers/usb/storage/sierra_ms.c
index 6ac60abd2e15..e605cbc3d8bf 100644
--- a/drivers/usb/storage/sierra_ms.c
+++ b/drivers/usb/storage/sierra_ms.c
@@ -194,8 +194,6 @@ int sierra_ms_init(struct us_data *us)
 		kfree(swocInfo);
 	}
 complete:
-	result = device_create_file(&us->pusb_intf->dev, &dev_attr_truinst);
-
-	return 0;
+	return device_create_file(&us->pusb_intf->dev, &dev_attr_truinst);
 }
 
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index a6d68191c861..047c5922618f 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -789,24 +789,33 @@ static int uas_slave_alloc(struct scsi_device *sdev)
 {
 	struct uas_dev_info *devinfo =
 		(struct uas_dev_info *)sdev->host->hostdata;
+	int maxp;
 
 	sdev->hostdata = devinfo;
 
 	/*
-	 * USB has unusual DMA-alignment requirements: Although the
-	 * starting address of each scatter-gather element doesn't matter,
-	 * the length of each element except the last must be divisible
-	 * by the Bulk maxpacket value.  There's currently no way to
-	 * express this by block-layer constraints, so we'll cop out
-	 * and simply require addresses to be aligned at 512-byte
-	 * boundaries.  This is okay since most block I/O involves
-	 * hardware sectors that are multiples of 512 bytes in length,
-	 * and since host controllers up through USB 2.0 have maxpacket
-	 * values no larger than 512.
+	 * We have two requirements here. We must satisfy the requirements
+	 * of the physical HC and the demands of the protocol, as we
+	 * definitely want no additional memory allocation in this path
+	 * ruling out using bounce buffers.
 	 *
-	 * But it doesn't suffice for Wireless USB, where Bulk maxpacket
-	 * values can be as large as 2048.  To make that work properly
-	 * will require changes to the block layer.
+	 * For a transmission on USB to continue we must never send
+	 * a package that is smaller than maxpacket. Hence the length of each
+         * scatterlist element except the last must be divisible by the
+         * Bulk maxpacket value.
+	 * If the HC does not ensure that through SG,
+	 * the upper layer must do that. We must assume nothing
+	 * about the capabilities off the HC, so we use the most
+	 * pessimistic requirement.
+	 */
+
+	maxp = usb_maxpacket(devinfo->udev, devinfo->data_in_pipe, 0);
+	blk_queue_virt_boundary(sdev->request_queue, maxp - 1);
+
+	/*
+	 * The protocol has no requirements on alignment in the strict sense.
+	 * Controllers may or may not have alignment restrictions.
+	 * As this is not exported, we use an extremely conservative guess.
 	 */
 	blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));
 
diff --git a/drivers/usb/storage/unusual_realtek.h b/drivers/usb/storage/unusual_realtek.h
index 6b2140f966ef..7e14c2d7cf73 100644
--- a/drivers/usb/storage/unusual_realtek.h
+++ b/drivers/usb/storage/unusual_realtek.h
@@ -17,6 +17,11 @@ UNUSUAL_DEV(0x0bda, 0x0138, 0x0000, 0x9999,
 		"USB Card Reader",
 		USB_SC_DEVICE, USB_PR_DEVICE, init_realtek_cr, 0),
 
+UNUSUAL_DEV(0x0bda, 0x0153, 0x0000, 0x9999,
+		"Realtek",
+		"USB Card Reader",
+		USB_SC_DEVICE, USB_PR_DEVICE, init_realtek_cr, 0),
+
 UNUSUAL_DEV(0x0bda, 0x0158, 0x0000, 0x9999,
 		"Realtek",
 		"USB Card Reader",