For failover handling, we will take the approach to resubmit each bio. However, unlike NVMe, for SCSI there is no guarantee that any bio submitted is either all or none completed.
As such, for SCSI, for failover handling we will take the approach to just re-submit the original bio. For this, clone and submit each bio. Signed-off-by: John Garry <[email protected]> --- drivers/scsi/scsi_multipath.c | 36 +++++++++++++++++++++++++++++++++-- include/scsi/scsi_multipath.h | 1 + 2 files changed, 35 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/scsi_multipath.c b/drivers/scsi/scsi_multipath.c index 6159803d4cbb8..ca4ab720c19af 100644 --- a/drivers/scsi/scsi_multipath.c +++ b/drivers/scsi/scsi_multipath.c @@ -96,6 +96,7 @@ static void scsi_mpath_head_release(struct device *dev) container_of(dev, struct scsi_mpath_head, dev); struct mpath_head *mpath_head = &scsi_mpath_head->mpath_head; + bioset_exit(&scsi_mpath_head->bio_pool); ida_free(&scsi_multipath_dev_ida, scsi_mpath_head->index); mpath_head_uninit(mpath_head); kfree(scsi_mpath_head); @@ -230,7 +231,34 @@ static int scsi_multipath_sdev_init(struct scsi_device *sdev) return 0; } +static void scsi_mpath_clone_end_io(struct bio *clone) +{ + struct bio *master_bio = clone->bi_private; + + master_bio->bi_status = clone->bi_status; + bio_put(clone); + bio_endio(master_bio); +} + +static struct bio *scsi_mpath_clone_bio(struct bio *bio) +{ + struct mpath_head *mpath_head = bio->bi_bdev->bd_disk->private_data; + struct scsi_mpath_head *scsi_mpath_head = to_scsi_mpath_head(mpath_head); + struct bio *clone; + + clone = bio_alloc_clone(bio->bi_bdev, bio, GFP_NOIO, + &scsi_mpath_head->bio_pool); + if (!clone) + return NULL; + + clone->bi_end_io = scsi_mpath_clone_end_io; + clone->bi_private = bio; + + return clone; +} + static struct mpath_head_template smpdt = { + .clone_bio = scsi_mpath_clone_bio, }; static struct scsi_mpath_head *scsi_mpath_alloc_head(void) @@ -244,9 +272,11 @@ static struct scsi_mpath_head *scsi_mpath_alloc_head(void) ida_init(&scsi_mpath_head->ida); - if (mpath_head_init(&scsi_mpath_head->mpath_head)) + if (bioset_init(&scsi_mpath_head->bio_pool, BIO_POOL_SIZE, + 0, BIOSET_PERCPU_CACHE)) goto out_free; - + if (mpath_head_init(&scsi_mpath_head->mpath_head)) + goto out_bioset_exit; scsi_mpath_head->mpath_head.mpdt = &smpdt; scsi_mpath_head->mpath_head.iopolicy = &scsi_mpath_head->iopolicy; @@ -270,6 +300,8 @@ static struct scsi_mpath_head *scsi_mpath_alloc_head(void) ida_free(&scsi_multipath_dev_ida, scsi_mpath_head->index); out_put_head: mpath_put_head(&scsi_mpath_head->mpath_head); +out_bioset_exit: + bioset_exit(&scsi_mpath_head->bio_pool); out_free: kfree(scsi_mpath_head); return NULL; diff --git a/include/scsi/scsi_multipath.h b/include/scsi/scsi_multipath.h index 2dc02313b0496..5cc37acaa664f 100644 --- a/include/scsi/scsi_multipath.h +++ b/include/scsi/scsi_multipath.h @@ -26,6 +26,7 @@ struct scsi_mpath_head { struct ida ida; struct kref ref; enum mpath_iopolicy_e iopolicy; + struct bio_set bio_pool; struct device dev; int index; }; -- 2.43.7
