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| author |   Kiyoshi Ueda <k-ueda@ct.jp.nec.com> | 2007-12-11 17:51:02 -0500 |
|---|---|---|
| committer |   Jens Axboe <jens.axboe@oracle.com> | 2008-01-28 10:37:04 +0100 |
| commit | e19a3ab058fe91c8c54d43dc56dccf7eb386478e (patch) | |
| tree | f62d5af2338484e8a3eec1dc453dec4f949024a7 /include | |
| parent | blk_end_request: changing ide normal caller (take 4) (diff) | |
| download | linux-dev-e19a3ab058fe91c8c54d43dc56dccf7eb386478e.tar.xz linux-dev-e19a3ab058fe91c8c54d43dc56dccf7eb386478e.zip | |
blk_end_request: add callback feature (take 4)
This patch adds a variant of the interface, blk_end_request_callback(),
which has driver callback feature.
Drivers may need to do special works between end_that_request_first()
and end_that_request_last().
For such drivers, blk_end_request_callback() allows it to pass
a callback function which is called between end_that_request_first()
and end_that_request_last().
This interface is only for fallback of other blk_end_request interfaces.
Drivers should avoid their tricky behaviors and use other interfaces
as much as possible.
Currently, only one driver, ide-cd, needs this interface.
So this interface should/will be removed, after the driver removes
such tricky behaviors.
o ide-cd (cdrom_newpc_intr())
In PIO mode, cdrom_newpc_intr() needs to defer end_that_request_last()
until the device clears DRQ_STAT and raises an interrupt after
end_that_request_first().
So end_that_request_first() and end_that_request_last() are called
separately in cdrom_newpc_intr().
This means blk_end_request_callback() has to return without
completing request even if no leftover in the request.
To satisfy the requirement, callback function has return value
so that drivers can tell blk_end_request_callback() to return
without completing request.
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index aa2341df7932..63fe7542b3fa 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -734,6 +734,8 @@ extern void end_that_request_last(struct request *, int); extern void end_request(struct request *, int); extern void end_queued_request(struct request *, int); extern void end_dequeued_request(struct request *, int); +extern int blk_end_request_callback(struct request *rq, int error, int nr_bytes, + int (drv_callback)(struct request *)); extern void blk_complete_request(struct request *); /* |