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Alan Stern 1186f86a71 UAS: Revert commit 3ae62a4209 ("UAS: fix alignment of scatter/gather segments")
Commit 3ae62a4209 ("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 09324d32d2 ("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 ea44d19076 ("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 3ae62a4209.

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: 3ae62a4209 ("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>
2019-10-28 17:53:39 +01:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-10-27 07:14:40 -04:00
block blk-rq-qos: fix first node deletion of rq_qos_del() 2019-10-15 10:13:13 -06:00
certs
crypto
Documentation ARM: SoC fixes 2019-10-25 16:00:47 -04:00
drivers UAS: Revert commit 3ae62a4209 ("UAS: fix alignment of scatter/gather segments") 2019-10-28 17:53:39 +01:00
fs Seven cifs/smb3 fixes, including three for stable 2019-10-27 06:41:52 -04:00
include Driver core fix for 5.4-rc5 2019-10-26 15:23:08 -04:00
init
ipc
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-10-27 07:04:22 -04:00
lib lib/vdso: Make clock_getres() POSIX compliant again 2019-10-23 14:48:23 +02:00
LICENSES
mm mm/thp: allow dropping THP from page cache 2019-10-19 06:32:33 -04:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-19 17:09:11 -04:00
samples samples/bpf: Add a workaround for asm_inline 2019-10-03 17:37:11 +02:00
scripts Modules fixes for v5.4-rc5 2019-10-25 16:11:55 -04:00
security selinux/stable-5.4 PR 20191007 2019-10-08 10:51:37 -07:00
sound ALSA: hda: Add Tigerlake/Jasperlake PCI ID 2019-10-23 06:28:50 +02:00
tools usbip: tools: Fix read_usb_vudc_device() error path handling 2019-10-28 17:51:06 +01:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM/arm fixes for 5.4, take #2 2019-10-22 13:31:29 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap A few MIPS fixes: 2019-10-26 19:43:12 -04:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS A few MIPS fixes: 2019-10-26 19:43:12 -04:00
Makefile Linux 5.4-rc5 2019-10-27 13:19:19 -04:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.