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ff2437befd
The PAGE_SHIFT alignment restriction to devm_gen_pool_create() quickly exhaust local memory because most allocations are much smaller than PAGE_SIZE. This causes USB device failures such as usb 1-2.1: reset full-speed USB device number 4 using sm501-usb sd 1:0:0:0: [sda] tag#0 UNKNOWN(0x2003) Result: hostbyte=0x03 driverbyte=0x00 sd 1:0:0:0: [sda] tag#0 CDB: opcode=0x28 28 00 00 00 08 7c 00 00 f0 00 print_req_error: I/O error, dev sda, sector 2172 flags 80700 when trying to boot from the SM501 USB controller on SH4 with QEMU. Align allocations as required but not necessarily much more than that. The HCCA, TD and ED structures align with 256, 32 and 16 byte memory boundaries, as specified by the Open HCI[1]. The min_alloc_order argument to devm_gen_pool_create is now somewhat arbitrarily set to 4 (16 bytes). Perhaps it could be somewhat lower for general buffer allocations. Reference: [1] "Open Host Controller Interface Specification for USB", release 1.0a, Compaq, Microsoft, National Semiconductor, 1999, pp. 16, 19, 33. Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Fredrik Noring <noring@nocrew.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Christoph Hellwig <hch@lst.de> |
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certs | ||
crypto | ||
Documentation | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
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mm | ||
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usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
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COPYING | ||
CREDITS | ||
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Makefile | ||
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.