Re: [RFC PATCH 3/3] blk-mq: Remove generation seqeunce

Bart Van Assche
2018-07-18T21:05:40Z

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On Wed, 2018-07-18 at 22:39 +-0200, hch+AEA-lst.de wrote:
+AD4- On Wed, Jul 18, 2018 at 09:56:50PM +-0200, hch+AEA-lst.de wrote:
+AD4- +AD4- The important bit is that we need to fix this issue quickly. W=
e are
+AD4- +AD4- past -rc5 so I'm rather concerned about anything too complicate=
d.
+AD4- +AD4-=20
+AD4- +AD4- I'm not even sure SCSI has a problem with multiple completions =
happening
+AD4- +AD4- at the same time, but it certainly has a problem with bypassing
+AD4- +AD4- blk+AF8-mq+AF8-complete+AF8-request from the EH path.
+AD4- +AD4-=20
+AD4- +AD4- I think we can solve this properly, but I also think we are way=
to late
+AD4- +AD4- in the 4.18 cycle to fix it properly. For now I fear we'll jus=
t have
+AD4- +AD4- to revert the changes and try again for 4.19 or even 4.20 if we=
don't
+AD4- +AD4- act quickly enough.
+AD4-=20
+AD4- So here is a quick attempt at the revert while also trying to keep
+AD4- nvme working. Keith, Bart, Jianchao - does this looks reasonable
+AD4- as a 4.18 band aid?
+AD4-=20
+AD4- http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/blk-=
eh-revert

Hello Christoph,

A patch series that first reverts the following patches:
+ACo- blk-mq: Fix timeout handling in case the timeout handler returns BLK+=
AF8-EH+AF8-DONE
+ACo- block: fix timeout changes for legacy request drivers
+ACo- blk-mq: don't time out requests again that are in the timeout handler
+ACo- blk-mq: simplify blk+AF8-mq+AF8-rq+AF8-timed+AF8-out
+ACo- block: remove BLK+AF8-EH+AF8-HANDLED
+ACo- block: rename BLK+AF8-EH+AF8-NOT+AF8-HANDLED to BLK+AF8-EH+AF8-DONE
+ACo- blk-mq: Remove generation seqeunce

and next renames BLK+AF8-EH+AF8-NOT+AF8-HANDLED again into BLK+AF8-EH+AF8-D=
ONE would probably be
a lot easier to review.

Thanks,

Bart.