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From: Ashlie Martinez <ashmrtn@utexas.edu>
To: linux-block@vger.kernel.org
Subject: RFC bio flags and ops in v4.10+
Date: Mon, 21 Jan 2019 20:45:09 -0800	[thread overview]
Message-ID: <CAFk8rvbdfzdChGf9jsTT7qPVf7bpW4VH0mys1He8_KjUD5mD2A@mail.gmail.com> (raw)

Hello,

I was working on porting parts of a file system crash consistency
checking tool called CrashMonkey [1] to linux kernels 4.9 and 4.14
when I noticed an inconsistency in how the bio->bi_opf field is
treated. According to the comments in /include/linux/blk_types.h, the
REQ_OP should be the upper bits in bi_opf, while the request flags
should be in the lower bits. In kernel 4.9, the accessor and setter
methods for this field appear to be correct. However, kernels 4.10+ do
not properly shift the REQ_OP argument up for either setting it or
getting it from bi_opf. Is this the intended behavior or is it a
mistake in how the code was written? Please note that I have not
checked all the releases between 4.9 and 5.0-rc3, but I know 4.10,
4.14, 4.15, and 5.0-rc3 contain the same or similar code for setting
bio->bi_opf.

[1] https://github.com/utsaslab/crashmonkey

             reply	other threads:[~2019-01-22  4:45 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-22  4:45 Ashlie Martinez [this message]
2019-01-22  5:04 ` RFC bio flags and ops in v4.10+ Bart Van Assche
2019-01-22  5:12   ` Ashlie Martinez
2019-01-22 17:05     ` Bart Van Assche

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