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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 /block/bio.c
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 'block/bio.c')
-rw-r--r--block/bio.c43
1 files changed, 18 insertions, 25 deletions
diff --git a/block/bio.c b/block/bio.c
index 2a00d349cd68..a23f489f398f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -269,7 +269,6 @@ static void bio_free(struct bio *bio)
void bio_init(struct bio *bio)
{
memset(bio, 0, sizeof(*bio));
- bio->bi_flags = 1 << BIO_UPTODATE;
atomic_set(&bio->__bi_remaining, 1);
atomic_set(&bio->__bi_cnt, 1);
}
@@ -292,14 +291,17 @@ void bio_reset(struct bio *bio)
__bio_free(bio);
memset(bio, 0, BIO_RESET_BYTES);
- bio->bi_flags = flags | (1 << BIO_UPTODATE);
+ bio->bi_flags = flags;
atomic_set(&bio->__bi_remaining, 1);
}
EXPORT_SYMBOL(bio_reset);
-static void bio_chain_endio(struct bio *bio, int error)
+static void bio_chain_endio(struct bio *bio)
{
- bio_endio(bio->bi_private, error);
+ struct bio *parent = bio->bi_private;
+
+ parent->bi_error = bio->bi_error;
+ bio_endio(parent);
bio_put(bio);
}
@@ -896,11 +898,11 @@ struct submit_bio_ret {
int error;
};
-static void submit_bio_wait_endio(struct bio *bio, int error)
+static void submit_bio_wait_endio(struct bio *bio)
{
struct submit_bio_ret *ret = bio->bi_private;
- ret->error = error;
+ ret->error = bio->bi_error;
complete(&ret->event);
}
@@ -1445,7 +1447,7 @@ void bio_unmap_user(struct bio *bio)
}
EXPORT_SYMBOL(bio_unmap_user);
-static void bio_map_kern_endio(struct bio *bio, int err)
+static void bio_map_kern_endio(struct bio *bio)
{
bio_put(bio);
}
@@ -1501,13 +1503,13 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
}
EXPORT_SYMBOL(bio_map_kern);
-static void bio_copy_kern_endio(struct bio *bio, int err)
+static void bio_copy_kern_endio(struct bio *bio)
{
bio_free_pages(bio);
bio_put(bio);
}
-static void bio_copy_kern_endio_read(struct bio *bio, int err)
+static void bio_copy_kern_endio_read(struct bio *bio)
{
char *p = bio->bi_private;
struct bio_vec *bvec;
@@ -1518,7 +1520,7 @@ static void bio_copy_kern_endio_read(struct bio *bio, int err)
p += bvec->bv_len;
}
- bio_copy_kern_endio(bio, err);
+ bio_copy_kern_endio(bio);
}
/**
@@ -1778,25 +1780,15 @@ static inline bool bio_remaining_done(struct bio *bio)
/**
* bio_endio - end I/O on a bio
* @bio: bio
- * @error: error, if any
*
* Description:
- * bio_endio() will end I/O on the whole bio. bio_endio() is the
- * preferred way to end I/O on a bio, it takes care of clearing
- * BIO_UPTODATE on error. @error is 0 on success, and and one of the
- * established -Exxxx (-EIO, for instance) error values in case
- * something went wrong. No one should call bi_end_io() directly on a
- * bio unless they own it and thus know that it has an end_io
- * function.
+ * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred
+ * way to end I/O on a bio. No one should call bi_end_io() directly on a
+ * bio unless they own it and thus know that it has an end_io function.
**/
-void bio_endio(struct bio *bio, int error)
+void bio_endio(struct bio *bio)
{
while (bio) {
- if (error)
- clear_bit(BIO_UPTODATE, &bio->bi_flags);
- else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
- error = -EIO;
-
if (unlikely(!bio_remaining_done(bio)))
break;
@@ -1810,11 +1802,12 @@ void bio_endio(struct bio *bio, int error)
*/
if (bio->bi_end_io == bio_chain_endio) {
struct bio *parent = bio->bi_private;
+ parent->bi_error = bio->bi_error;
bio_put(bio);
bio = parent;
} else {
if (bio->bi_end_io)
- bio->bi_end_io(bio, error);
+ bio->bi_end_io(bio);
bio = NULL;
}
}