Length parameter of io_sg_from_iter() can be smaller than the iterator's size, as it's with TCP, so when we set from->count at the end of the function we truncate the iterator forcing TCP to return preliminary with a short send. It affects zerocopy sends with large payload sizes and leads to retries and possible request failures. Fixes: 3ff1a0d395c00 ("io_uring: enable managed frags with register buffers") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/0bc0d5179c665b4ef5c328377c84c7a1f298467e.1661530037.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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.
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