android_kernel_oneplus_msm8998/drivers/usb/storage
Alan Stern 57d1b56857 UAS: Revert commit 3ae62a42090f ("UAS: fix alignment of scatter/gather segments")
commit 1186f86a71130a7635a20843e355bb880c7349b2 upstream.

Commit 3ae62a42090f ("UAS: fix alignment of scatter/gather segments"),
copying a similar commit for usb-storage, attempted to solve a problem
involving scatter-gather I/O and USB/IP by setting the
virt_boundary_mask for mass-storage devices.

However, it now turns out that the analogous change in usb-storage
interacted badly with commit 09324d32d2a0 ("block: force an unlimited
segment size on queues with a virt boundary"), which was added later.
A typical error message is:

	ehci-pci 0000:00:13.2: swiotlb buffer is full (sz: 327680 bytes),
	total 32768 (slots), used 97 (slots)

There is no longer any reason to keep the virt_boundary_mask setting
in the uas driver.  It was needed in the first place only for
handling devices with a block size smaller than the maxpacket size and
where the host controller was not capable of fully general
scatter-gather operation (that is, able to merge two SG segments into
a single USB packet).  But:

	High-speed or slower connections never use a bulk maxpacket
	value larger than 512;

	The SCSI layer does not handle block devices with a block size
	smaller than 512 bytes;

	All the host controllers capable of SuperSpeed operation can
	handle fully general SG;

	Since commit ea44d190764b ("usbip: Implement SG support to
	vhci-hcd and stub driver") was merged, the USB/IP driver can
	also handle SG.

Therefore all supported device/controller combinations should be okay
with no need for any special virt_boundary_mask.  So in order to head
off potential problems similar to those affecting usb-storage, this
patch reverts commit 3ae62a42090f.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Oliver Neukum <oneukum@suse.com>
CC: <stable@vger.kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Fixes: 3ae62a42090f ("UAS: fix alignment of scatter/gather segments")
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1910231132470.1878-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-06 12:09:18 +01:00
..
alauda.c
cypress_atacb.c
datafab.c
debug.c
debug.h
ene_ub6250.c
freecom.c
initializers.c
initializers.h
isd200.c
jumpshot.c
karma.c
Kconfig
Makefile
onetouch.c
option_ms.c
option_ms.h
protocol.c
protocol.h
realtek_cr.c USB: storage: ums-realtek: Whitelist auto-delink support 2019-09-06 10:18:16 +02:00
scsiglue.c
scsiglue.h
sddr09.c
sddr55.c
shuttle_usbat.c
sierra_ms.c
sierra_ms.h
transport.c
transport.h
uas-detect.h
uas.c UAS: Revert commit 3ae62a42090f ("UAS: fix alignment of scatter/gather segments") 2019-11-06 12:09:18 +01:00
unusual_alauda.h
unusual_cypress.h
unusual_datafab.h
unusual_devs.h usb-storage: Add new JMS567 revision to unusual_devs 2019-09-06 10:18:16 +02:00
unusual_ene_ub6250.h
unusual_freecom.h
unusual_isd200.h
unusual_jumpshot.h
unusual_karma.h
unusual_onetouch.h
unusual_realtek.h USB: usb-storage: Add new ID to ums-realtek 2019-06-22 08:18:24 +02:00
unusual_sddr09.h
unusual_sddr55.h
unusual_uas.h
unusual_usbat.h
usb.c
usb.h
usual-tables.c