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authorKiyoshi Ueda <k-ueda@ct.jp.nec.com>2007-12-11 17:40:30 -0500
committerJens Axboe <jens.axboe@oracle.com>2008-01-28 10:35:53 +0100
commit336cdb4003200a90f4fc52a4e9ccc2baa570fffb (patch)
treedcb7f736738232c0e853a1ba796ca35d5b18c503
parent91525300baf162e83e923b09ca286f9205e21522 (diff)
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 <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>
-rw-r--r--block/ll_rw_blk.c96
-rw-r--r--include/linux/blkdev.h4
2 files changed, 100 insertions, 0 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 3d0422f4845..5c01911af47 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 49b7a4c31a6..3b212f02db8 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);