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authorChristoph Hellwig <hch@lst.de>2015-07-20 16:29:37 +0300
committerJens Axboe <axboe@fb.com>2015-07-29 17:55:15 +0300
commit4246a0b63bd8f56a1469b12eafeb875b1041a451 (patch)
tree3281bb158d658ef7f208ad380c0ecee600a5ab5e /Documentation
parent0034af036554c39eefd14d835a8ec3496ac46712 (diff)
downloadlinux-4246a0b63bd8f56a1469b12eafeb875b1041a451.tar.xz
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 'Documentation')
-rw-r--r--Documentation/block/biodoc.txt2
1 files changed, 1 insertions, 1 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index fd12c0d835fd..5be8a7f4cc7f 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -1109,7 +1109,7 @@ it will loop and handle as many sectors (on a bio-segment granularity)
as specified.
Now bh->b_end_io is replaced by bio->bi_end_io, but most of the time the
-right thing to use is bio_endio(bio, uptodate) instead.
+right thing to use is bio_endio(bio) instead.
If the driver is dropping the io_request_lock from its request_fn strategy,
then it just needs to replace that with q->queue_lock instead.