block: convert blkdev_issue_flush() to use empty barriers
Then we can get rid of ->issue_flush_fn() and all the driver private
implementations of that.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 4fde3a3..4df7d02 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -304,23 +304,6 @@
EXPORT_SYMBOL(blk_queue_ordered);
-/**
- * blk_queue_issue_flush_fn - set function for issuing a flush
- * @q: the request queue
- * @iff: the function to be called issuing the flush
- *
- * Description:
- * If a driver supports issuing a flush command, the support is notified
- * to the block layer by defining it through this call.
- *
- **/
-void blk_queue_issue_flush_fn(struct request_queue *q, issue_flush_fn *iff)
-{
- q->issue_flush_fn = iff;
-}
-
-EXPORT_SYMBOL(blk_queue_issue_flush_fn);
-
/*
* Cache flushing for ordered writes handling
*/
@@ -2666,6 +2649,14 @@
EXPORT_SYMBOL(blk_execute_rq);
+static void bio_end_empty_barrier(struct bio *bio, int err)
+{
+ if (err)
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+
+ complete(bio->bi_private);
+}
+
/**
* blkdev_issue_flush - queue a flush
* @bdev: blockdev to issue flush for
@@ -2678,7 +2669,10 @@
*/
int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
{
+ DECLARE_COMPLETION_ONSTACK(wait);
struct request_queue *q;
+ struct bio *bio;
+ int ret;
if (bdev->bd_disk == NULL)
return -ENXIO;
@@ -2686,10 +2680,32 @@
q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
- if (!q->issue_flush_fn)
- return -EOPNOTSUPP;
- return q->issue_flush_fn(q, bdev->bd_disk, error_sector);
+ bio = bio_alloc(GFP_KERNEL, 0);
+ if (!bio)
+ return -ENOMEM;
+
+ bio->bi_end_io = bio_end_empty_barrier;
+ bio->bi_private = &wait;
+ bio->bi_bdev = bdev;
+ submit_bio(1 << BIO_RW_BARRIER, bio);
+
+ wait_for_completion(&wait);
+
+ /*
+ * The driver must store the error location in ->bi_sector, if
+ * it supports it. For non-stacked drivers, this should be copied
+ * from rq->sector.
+ */
+ if (error_sector)
+ *error_sector = bio->bi_sector;
+
+ ret = 0;
+ if (!bio_flagged(bio, BIO_UPTODATE))
+ ret = -EIO;
+
+ bio_put(bio);
+ return ret;
}
EXPORT_SYMBOL(blkdev_issue_flush);