blkdev_issue_flush() is a blocking function and returns only after
the flush bio is completed, so a module handling more than one
device can't issue flush for all the devices unless it uses worker
thread.
This patch adds a new function blkdev_issue_flush_no_wait(), which
uses submit_bio() instead of submit_bio_wait(), and accepts the
completion function and data from the caller.
Signed-off-by: Anand Jain <anand.jain@xxxxxxxxxx>
---
block/blk-flush.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
include/linux/blkdev.h | 8 ++++++++
2 files changed, 55 insertions(+)
diff --git a/block/blk-flush.c b/block/blk-flush.c
index c4e0880b54bb..16b9c61f4cd3 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -488,6 +488,53 @@ void blk_insert_flush(struct request *rq)
blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0);
}
+/*
+ * blkdev_issue_flush_no_wait - Issue a flush for the given block device
+ * @bdev: blockdev to issue flush for
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @endio_fn: completion function for the flush bio
+ * @data: flush bio private data
+ *
+ * Description:
+ * Issue a flush for the block device in question. Caller must provide
+ * the completion function and the private data, to be called when the
+ * issued flush bio completes.
+ */
+int blkdev_issue_flush_no_wait(struct block_device *bdev, gfp_t gfp_mask,
+ bio_end_io_t *endio_fn, void *data)
+{
+ struct request_queue *q;
+ struct bio *bio;
+
+ if (bdev->bd_disk == NULL)
+ return -ENXIO;
+
+ q = bdev_get_queue(bdev);
+ if (!q)
+ return -ENXIO;
+
+ /*
+ * some block devices may not have their queue correctly set up here
+ * (e.g. loop device without a backing file) and so issuing a flush
+ * here will panic. Ensure there is a request function before issuing
+ * the flush.
+ */
+ if (!q->make_request_fn)
+ return -ENXIO;
+
+ bio = bio_alloc(gfp_mask, 0);
+ bio->bi_bdev = bdev;
+ bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
+ bio->bi_end_io = endio_fn;
+ bio->bi_private = data;
+
+ init_completion(data);
+ submit_bio(bio);
+
+ return 0;
+}
+EXPORT_SYMBOL(blkdev_issue_flush_no_wait);
+
/**
* blkdev_issue_flush - queue a flush
* @bdev: blockdev to issue flush for
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b5d1e27631ee..5d2b62239251 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1322,6 +1322,8 @@ static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
}
extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *);
+extern int blkdev_issue_flush_no_wait(struct block_device *bdev,
+ gfp_t gfp_mask, bio_end_io_t *endio_fn, void *data);
extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct page *page);
@@ -1994,6 +1996,12 @@ static inline int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
return 0;
}
+static inline int blkdev_issue_flush_no_wait(struct block_device *bdev,
+ gfp_t gfp_mask, bio_end_io_t *endio_fn, void *data)
+{
+ return 0;
+}
+
#endif /* CONFIG_BLOCK */
#endif
--
2.10.0
