From: Kiyoshi Ueda Date: Tue, 11 Dec 2007 22:40:30 +0000 (-0500) Subject: blk_end_request: add new request completion interface (take 4) X-Git-Tag: v2.6.25-rc1~1172^2~29 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=336cdb4003200a90f4fc52a4e9ccc2baa570fffb;p=linux-2.6 blk_end_request: add new request completion interface (take 4) This patch adds 2 new interfaces for request completion: o blk_end_request() : called without queue lock o __blk_end_request() : called with queue lock held blk_end_request takes 'error' as an argument instead of 'uptodate', which current end_that_request_* take. The meanings of values are below and the value is used when bio is completed. 0 : success < 0 : error Some device drivers call some generic functions below between end_that_request_{first/chunk} and end_that_request_last(). o add_disk_randomness() o blk_queue_end_tag() o blkdev_dequeue_request() These are called in the blk_end_request interfaces as a part of generic request completion. So all device drivers become to call above functions. To decide whether to call blkdev_dequeue_request(), blk_end_request uses list_empty(&rq->queuelist) (blk_queued_rq() macro is added for it). So drivers must re-initialize it using list_init() or so before calling blk_end_request if drivers use it for its specific purpose. (Currently, there is no driver which completes request without re-initializing the queuelist after used it. So rq->queuelist can be used for the purpose above.) "Normal" drivers can be converted to use blk_end_request() in a standard way shown below. a) end_that_request_{chunk/first} spin_lock_irqsave() (add_disk_randomness(), blk_queue_end_tag(), blkdev_dequeue_request()) end_that_request_last() spin_unlock_irqrestore() => blk_end_request() b) spin_lock_irqsave() end_that_request_{chunk/first} (add_disk_randomness(), blk_queue_end_tag(), blkdev_dequeue_request()) end_that_request_last() spin_unlock_irqrestore() => spin_lock_irqsave() __blk_end_request() spin_unlock_irqsave() c) spin_lock_irqsave() (add_disk_randomness(), blk_queue_end_tag(), blkdev_dequeue_request()) end_that_request_last() spin_unlock_irqrestore() => blk_end_request() or spin_lock_irqsave() __blk_end_request() spin_unlock_irqrestore() Signed-off-by: Kiyoshi Ueda Signed-off-by: Jun'ichi Nomura Signed-off-by: Jens Axboe --- diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index 3d0422f484..5c01911af4 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -3791,6 +3791,102 @@ void end_request(struct request *req, int uptodate) } EXPORT_SYMBOL(end_request); +static void complete_request(struct request *rq, int error) +{ + /* + * REMOVEME: This conversion is transitional and will be removed + * when old end_that_request_* are unexported. + */ + int uptodate = 1; + if (error) + uptodate = (error == -EIO) ? 0 : error; + + if (blk_rq_tagged(rq)) + blk_queue_end_tag(rq->q, rq); + + if (blk_queued_rq(rq)) + blkdev_dequeue_request(rq); + + end_that_request_last(rq, uptodate); +} + +/** + * blk_end_request - Helper function for drivers to complete the request. + * @rq: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Ends I/O on a number of bytes attached to @rq. + * If @rq has leftover, sets it up for the next range of segments. + * + * Return: + * 0 - we are done with this request + * 1 - still buffers pending for this request + **/ +int blk_end_request(struct request *rq, int error, int nr_bytes) +{ + struct request_queue *q = rq->q; + unsigned long flags = 0UL; + /* + * REMOVEME: This conversion is transitional and will be removed + * when old end_that_request_* are unexported. + */ + int uptodate = 1; + if (error) + uptodate = (error == -EIO) ? 0 : error; + + if (blk_fs_request(rq) || blk_pc_request(rq)) { + if (__end_that_request_first(rq, uptodate, nr_bytes)) + return 1; + } + + add_disk_randomness(rq->rq_disk); + + spin_lock_irqsave(q->queue_lock, flags); + complete_request(rq, error); + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; +} +EXPORT_SYMBOL_GPL(blk_end_request); + +/** + * __blk_end_request - Helper function for drivers to complete the request. + * @rq: the request being processed + * @error: 0 for success, < 0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Must be called with queue lock held unlike blk_end_request(). + * + * Return: + * 0 - we are done with this request + * 1 - still buffers pending for this request + **/ +int __blk_end_request(struct request *rq, int error, int nr_bytes) +{ + /* + * REMOVEME: This conversion is transitional and will be removed + * when old end_that_request_* are unexported. + */ + int uptodate = 1; + if (error) + uptodate = (error == -EIO) ? 0 : error; + + if (blk_fs_request(rq) || blk_pc_request(rq)) { + if (__end_that_request_first(rq, uptodate, nr_bytes)) + return 1; + } + + add_disk_randomness(rq->rq_disk); + + complete_request(rq, error); + + return 0; +} +EXPORT_SYMBOL_GPL(__blk_end_request); + static void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio) { diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 49b7a4c31a..3b212f02db 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -537,6 +537,8 @@ enum { #define blk_fua_rq(rq) ((rq)->cmd_flags & REQ_FUA) #define blk_bidi_rq(rq) ((rq)->next_rq != NULL) #define blk_empty_barrier(rq) (blk_barrier_rq(rq) && blk_fs_request(rq) && !(rq)->hard_nr_sectors) +/* rq->queuelist of dequeued request must be list_empty() */ +#define blk_queued_rq(rq) (!list_empty(&(rq)->queuelist)) #define list_entry_rq(ptr) list_entry((ptr), struct request, queuelist) @@ -724,6 +726,8 @@ static inline void blk_run_address_space(struct address_space *mapping) * for parts of the original function. This prevents * code duplication in drivers. */ +extern int blk_end_request(struct request *rq, int error, int nr_bytes); +extern int __blk_end_request(struct request *rq, int error, int nr_bytes); extern int end_that_request_first(struct request *, int, int); extern int end_that_request_chunk(struct request *, int, int); extern void end_that_request_last(struct request *, int);