On Thu, 2017-06-01 at 12:06 -0700, Jens Axboe wrote:

On 06/01/2017 06:11 AM, Bart Van Assche wrote:

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On Thu, 2017-06-01 at 08:08 +0200, Christoph Hellwig wrote:

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On Wed, May 31, 2017 at 03:52:46PM -0700, Bart Van Assche wrote:

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Commit 6d247d7f71d1 ("block: allow specifying size for extra comman=

d

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data") added support for .cmd_size to blk-sq. Due to that patch the
blk_mq_rq_{to,from}_pdu() functions are also useful for single-queu=

e

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block drivers. Hence remove "_mq" from the name of these functions.
This patch does not change any functionality. Most of this patch ha=

s

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been generated by running the following shell command:

=20
I don't really see the point of this as it's primarily a blk-mq API
and we still hope to get rid of the old code.  But I'm not necessaril=

y

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against it either.

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I would like to introduce calls to these functions in several scsi-sq
functions. If I would do that without renaming these functions then any=

one

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who reads the code of these functions and sees calls to functions with =

a

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blk_mq_ prefix could get really confused when trying to figure out whet=

her

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these functions are used by scsi-sq, scsi-mq or perhaps both.

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But that should go away, eventually.

Hello Jens,

I agree that we should work towards removal of the single queue block layer=
.
But how long will it take before that code is removed?

Due to recent patches from Christoph the 'request' member in struct scsi_cm=
nd
is now superfluous. I'd like to replace accesses to that member by a call t=
o
blk_mq_rq_from_pdu(). I'm afraid that doing that in scsi-sq code paths will
make that code look weird.

Bart.=