forked from luck/tmp_suning_uos_patched
bb175342aa
Setting and clearing REQ_F_OVERFLOW in io_uring_cancel_files() and io_cqring_overflow_flush() are racy, because they might be called asynchronously. REQ_F_OVERFLOW flag in only needed for files cancellation, so if it can be guaranteed that requests _currently_ marked inflight can't be overflown, the problem will be solved with removing the flag altogether. That's how the patch works, it removes inflight status of a request in io_cqring_fill_event() whenever it should be thrown into CQ-overflow list. That's Ok to do, because no opcode specific handling can be done after io_cqring_fill_event(), the same assumption as with "struct io_completion" patches. And it already have a good place for such cleanups, which is io_clean_op(). A nice side effect of this is removing this inflight check from the hot path. note on synchronisation: now __io_cqring_fill_event() may be taking two spinlocks simultaneously, completion_lock and inflight_lock. It's fine, because we never do that in reverse order, and CQ-overflow of inflight requests shouldn't happen often. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.