From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Set queue flags to QUEUE_FLAG_NOWAIT to indicate REQ_NOWAIT
will be handled. If any of the underlying devices do not support
NOWAIT feature, we do not set the flag.
If the device is suspended, it returns -EWOULDBLOCK.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
drivers/md/md.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 0ff1bbf6c90e..7325f8be36b4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -237,6 +237,19 @@ EXPORT_SYMBOL_GPL(md_new_event);
static LIST_HEAD(all_mddevs);
static DEFINE_SPINLOCK(all_mddevs_lock);
+static bool is_suspended(struct mddev *mddev, struct bio *bio)
+{
+ /* We can serve READ requests when device is suspended */
+ if (bio_data_dir(bio) == READ)
+ return false;
+
+ if (mddev->suspended)
+ return true;
+
+ return (mddev->suspend_lo < bio_end_sector(bio) &&
+ mddev->suspend_hi > bio->bi_iter.bi_sector);
+}
+
/*
* iterates through all used mddevs in the system.
* We take care to grab the all_mddevs_lock whenever navigating
@@ -316,6 +329,11 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio)
bio_endio(bio);
return BLK_QC_T_NONE;
}
+ /* Bail out if we would have to wait for suspended device */
+ if ((bio->bi_opf & REQ_NOWAIT) && is_suspended(mddev, bio)) {
+ bio_wouldblock_error(bio);
+ return BLK_QC_T_NONE;
+ }
/*
* save the sectors now since our bio can
@@ -5404,6 +5422,7 @@ int md_run(struct mddev *mddev)
int err;
struct md_rdev *rdev;
struct md_personality *pers;
+ bool nowait = true;
if (list_empty(&mddev->disks))
/* cannot run an array with no devices.. */
@@ -5470,8 +5489,15 @@ int md_run(struct mddev *mddev)
}
}
sysfs_notify_dirent_safe(rdev->sysfs_state);
+ if (!blk_queue_supports_nowait(rdev->bdev->bd_queue))
+ nowait = false;
}
+ /* Set the NOWAIT flags if all underlying devices support it */
+ if (nowait)
+ queue_flag_set_unlocked(QUEUE_FLAG_NOWAIT, mddev->queue);
+
+
if (mddev->bio_set == NULL) {
mddev->bio_set = bioset_create(BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
if (!mddev->bio_set)
@@ -6554,6 +6580,15 @@ static int hot_add_disk(struct mddev *mddev, dev_t dev)
set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
if (!mddev->thread)
md_update_sb(mddev, 1);
+
+ /* If the new disk does not support REQ_NOWAIT,
+ disable on whole MD */
+ if (!blk_queue_supports_nowait(rdev->bdev->bd_queue)) {
+ pr_info("%s: Disabling nowait because %s does not support nowait\n",
+ mdname(mddev), bdevname(rdev->bdev,b));
+ queue_flag_clear_unlocked(QUEUE_FLAG_NOWAIT, mddev->queue);
+ }
+
/*
* Kick recovery, maybe this spare has to be added to the
* array immediately.
--
2.14.2
