747668dbc0
The USB subsystem has always had an unusual requirement for its scatter-gather transfers: Each element in the scatterlist (except the last one) must have a length divisible by the bulk maxpacket size. This is a particular issue for USB mass storage, which uses SG lists created by the block layer rather than setting up its own. So far we have scraped by okay because most devices have a logical block size of 512 bytes or larger, and the bulk maxpacket sizes for USB 2 and below are all <= 512. However, USB 3 has a bulk maxpacket size of 1024. Since the xhci-hcd driver includes native SG support, this hasn't mattered much. But now people are trying to use USB-3 mass storage devices with USBIP, and the vhci-hcd driver currently does not have full SG support. The result is an overflow error, when the driver attempts to implement an SG transfer of 63 512-byte blocks as a single 3584-byte (7 blocks) transfer followed by seven 4096-byte (8 blocks) transfers. The device instead sends 31 1024-byte packets followed by a 512-byte packet, and this overruns the first SG buffer. Ideally this would be fixed by adding better SG support to vhci-hcd. But for now it appears we can work around the problem by asking the block layer to respect the maxpacket limitation, through the use of the virt_boundary_mask. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Seth Bollinger <Seth.Bollinger@digi.com> Tested-by: Seth Bollinger <Seth.Bollinger@digi.com> CC: Ming Lei <tom.leiming@gmail.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.