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authorChristoph Hellwig <hch@lst.de>2015-07-20 15:29:37 +0200
committerJens Axboe <axboe@fb.com>2015-07-29 08:55:15 -0600
commit4246a0b63bd8f56a1469b12eafeb875b1041a451 (patch)
tree3281bb158d658ef7f208ad380c0ecee600a5ab5e /block/blk-lib.c
parent0034af036554c39eefd14d835a8ec3496ac46712 (diff)
downloadlinux-linaro-stable-4246a0b63bd8f56a1469b12eafeb875b1041a451.tar.gz
block: add a bi_error field to struct bio
Currently we have two different ways to signal an I/O error on a BIO: (1) by clearing the BIO_UPTODATE flag (2) by returning a Linux errno value to the bi_end_io callback The first one has the drawback of only communicating a single possible error (-EIO), and the second one has the drawback of not beeing persistent when bios are queued up, and are not passed along from child to parent bio in the ever more popular chaining scenario. Having both mechanisms available has the additional drawback of utterly confusing driver authors and introducing bugs where various I/O submitters only deal with one of them, and the others have to add boilerplate code to deal with both kinds of error returns. So add a new bi_error field to store an errno value directly in struct bio and remove the existing mechanisms to clean all this up. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-lib.c')
-rw-r--r--block/blk-lib.c30
1 files changed, 13 insertions, 17 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 7688ee3f5d72..6dee17443f14 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -11,16 +11,16 @@
struct bio_batch {
atomic_t done;
- unsigned long flags;
+ int error;
struct completion *wait;
};
-static void bio_batch_end_io(struct bio *bio, int err)
+static void bio_batch_end_io(struct bio *bio)
{
struct bio_batch *bb = bio->bi_private;
- if (err && (err != -EOPNOTSUPP))
- clear_bit(BIO_UPTODATE, &bb->flags);
+ if (bio->bi_error && bio->bi_error != -EOPNOTSUPP)
+ bb->error = bio->bi_error;
if (atomic_dec_and_test(&bb->done))
complete(bb->wait);
bio_put(bio);
@@ -78,7 +78,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
}
atomic_set(&bb.done, 1);
- bb.flags = 1 << BIO_UPTODATE;
+ bb.error = 0;
bb.wait = &wait;
blk_start_plug(&plug);
@@ -134,9 +134,8 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
if (!atomic_dec_and_test(&bb.done))
wait_for_completion_io(&wait);
- if (!test_bit(BIO_UPTODATE, &bb.flags))
- ret = -EIO;
-
+ if (bb.error)
+ return bb.error;
return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);
@@ -172,7 +171,7 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
return -EOPNOTSUPP;
atomic_set(&bb.done, 1);
- bb.flags = 1 << BIO_UPTODATE;
+ bb.error = 0;
bb.wait = &wait;
while (nr_sects) {
@@ -208,9 +207,8 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
if (!atomic_dec_and_test(&bb.done))
wait_for_completion_io(&wait);
- if (!test_bit(BIO_UPTODATE, &bb.flags))
- ret = -ENOTSUPP;
-
+ if (bb.error)
+ return bb.error;
return ret;
}
EXPORT_SYMBOL(blkdev_issue_write_same);
@@ -236,7 +234,7 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
DECLARE_COMPLETION_ONSTACK(wait);
atomic_set(&bb.done, 1);
- bb.flags = 1 << BIO_UPTODATE;
+ bb.error = 0;
bb.wait = &wait;
ret = 0;
@@ -270,10 +268,8 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
if (!atomic_dec_and_test(&bb.done))
wait_for_completion_io(&wait);
- if (!test_bit(BIO_UPTODATE, &bb.flags))
- /* One of bios in the batch was completed with error.*/
- ret = -EIO;
-
+ if (bb.error)
+ return bb.error;
return ret;
}