The current autocork algorithms will delay the data transmission in BH context to smc_release_cb() when sock_lock is hold by user. So there is a possibility that when connection is being actively closed (sock_lock is hold by user now), some corked data still remains in sndbuf, waiting to be sent by smc_release_cb(). This will cause: - smc_close_stream_wait(), which is called under the sock_lock, has a high probability of timeout because data transmission is delayed until sock_lock is released. - Unexpected data sends may happen after connction closed and use the rtoken which has been deleted by remote peer through LLC_DELETE_RKEY messages. So this patch will try to send out the remaining corked data in sndbuf before active close process, to ensure data integrity and avoid unexpected data transmission after close. Reported-by: Guangguan Wang <guangguan.wang@linux.alibaba.com> Fixes: 6b88af839d20 ("net/smc: don't send in the BH context if sock_owned_by_user") Signed-off-by: Wen Gu <guwen@linux.alibaba.com> Acked-by: Karsten Graul <kgraul@linux.ibm.com> Link: https://lore.kernel.org/r/1648447836-111521-1-git-send-email-guwen@linux.alibaba.com Signed-off-by: Jakub Kicinski <kuba@kernel.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 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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