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David Howells
4fe38acdac
It is necessary to allow MSG_SENDPAGE_* to be passed into ->sendmsg() to allow sendmsg(MSG_SPLICE_PAGES) to replace ->sendpage(). Unblocking them in the network protocol, however, allows these flags to be passed in by userspace too[1]. Fix this by marking MSG_SENDPAGE_NOPOLICY, MSG_SENDPAGE_NOTLAST and MSG_SENDPAGE_DECRYPTED as internal flags, which causes sendmsg() to object if they are passed to sendmsg() by userspace. Network protocol ->sendmsg() implementations can then allow them through. Note that it should be possible to remove MSG_SENDPAGE_NOTLAST once sendpage is removed as a whole slew of pages will be passed in in one go by splice through sendmsg, with MSG_MORE being set if it has more data waiting in the pipe. Signed-off-by: David Howells <[email protected]> cc: Chuck Lever <[email protected]> cc: Boris Pismenny <[email protected]> cc: John Fastabend <[email protected]> cc: Jens Axboe <[email protected]> cc: Matthew Wilcox <[email protected]> Link: https://lore.kernel.org/r/[email protected]/ [1] Signed-off-by: Jakub Kicinski <[email protected]>
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.