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Kees Cook
2bb6b10ebe
Since the beginning of time, struct usb_ep::maxpacket was a bitfield, and when new 16-bit members were added, the convention was followed:1da177e4c3(Linus Torvalds 2005-04-16 236) unsigned maxpacket:16;e117e742d3(Robert Baldyga 2013-12-13 237) unsigned maxpacket_limit:16;a59d6b91cb(Tatyana Brokhman 2011-06-28 238) unsigned max_streams:16; However, there is no need for this as a simple u16 can be used instead, simplifying the struct and the resulting compiler binary output. Switch to u16 for all three, and rearrange struct slightly to minimize holes. No change in the final size of the struct results; the 2 byte gap is just moved to the end, as seen with pahole: - /* XXX 2 bytes hole, try to pack */ ... /* size: 72, cachelines: 2, members: 15 */ ... + /* padding: 2 */ Changing this simplifies future introspection[1] of maxpacket's type during allocations: drivers/usb/gadget/function/f_tcm.c:330:24: error: 'typeof' applied to a bit-field 330 | fu->cmd.buf = kmalloc(fu->ep_out->maxpacket, GFP_KERNEL); Link: https://lore.kernel.org/all/202407090928.6UaOAZAJ-lkp@intel.com [1] Signed-off-by: Kees Cook <kees@kernel.org> Link: https://lore.kernel.org/r/20240709154953.work.953-kees@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 reStructuredText 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.