From e19a3ab058fe91c8c54d43dc56dccf7eb386478e Mon Sep 17 00:00:00 2001 From: Kiyoshi Ueda Date: Tue, 11 Dec 2007 17:51:02 -0500 Subject: 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 Signed-off-by: Jun'ichi Nomura Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/blkdev.h') 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 *); /* -- cgit v1.2.3