Merge tag 'usb-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB/PHY updates from Greg KH:
 "Here is the big set of USB and PHY driver patches for 5.2-rc1

  There is the usual set of:

   - USB gadget updates

   - PHY driver updates and additions

   - USB serial driver updates and fixes

   - typec updates and new chips supported

   - mtu3 driver updates

   - xhci driver updates

   - other tiny driver updates

  Nothing really interesting, just constant forward progress.

  All of these have been in linux-next for a while with no reported
  issues. The usb-gadget and usb-serial trees were merged a bit "late",
  but both of them had been in linux-next before they got merged here
  last Friday"

* tag 'usb-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (206 commits)
  USB: serial: f81232: implement break control
  USB: serial: f81232: add high baud rate support
  USB: serial: f81232: clear overrun flag
  USB: serial: f81232: fix interrupt worker not stop
  usb: dwc3: Rename DWC3_DCTL_LPM_ERRATA
  usb: dwc3: Fix default lpm_nyet_threshold value
  usb: dwc3: debug: Print GET_STATUS(device) tracepoint
  usb: dwc3: Do core validation early on probe
  usb: dwc3: gadget: Set lpm_capable
  usb: gadget: atmel: tie wake lock to running clock
  usb: gadget: atmel: support USB suspend
  usb: gadget: atmel_usba_udc: simplify setting of interrupt-enabled mask
  dwc2: gadget: Fix completed transfer size calculation in DDMA
  usb: dwc2: Set lpm mode parameters depend on HW configuration
  usb: dwc2: Fix channel disable flow
  usb: dwc2: Set actual frame number for completed ISOC transfer
  usb: gadget: do not use __constant_cpu_to_le16
  usb: dwc2: gadget: Increase descriptors count for ISOC's
  usb: introduce usb_ep_type_string() function
  usb: dwc3: move synchronize_irq() out of the spinlock protected block
  ...

3 files changed, 35 insertions, 30 deletions

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index a73ea495d5a7b..59190d88fa9f3 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));
 
diff --git a/drivers/usb/storage/sierra_ms.c b/drivers/usb/storage/sierra_ms.c
index 6ac60abd2e15c..e605cbc3d8bf2 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 a6d68191c8617..047c5922618f8 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));