[dm-devel] [PATCH RFC 7/7] dm: add support for IO polling
Jeffle Xu
jefflexu at linux.alibaba.com
Wed Dec 23 11:26:24 UTC 2020
Enable iopoll when all underlying target devices supports iopoll.
Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
---
drivers/md/dm-table.c | 28 ++++++++++++++++++++++++++++
drivers/md/dm.c | 1 +
2 files changed, 29 insertions(+)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 188f41287f18..b0cd5bf58c3c 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1791,6 +1791,31 @@ static bool dm_table_requires_stable_pages(struct dm_table *t)
return false;
}
+static int device_supports_poll(struct dm_target *ti, struct dm_dev *dev,
+ sector_t start, sector_t len, void *data)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+
+ return q && test_bit(QUEUE_FLAG_POLL, &q->queue_flags);
+}
+
+static bool dm_table_supports_poll(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned int i;
+
+ /* Ensure that all targets support iopoll. */
+ for (i = 0; i < dm_table_get_num_targets(t); i++) {
+ ti = dm_table_get_target(t, i);
+
+ if (!ti->type->iterate_devices ||
+ !ti->type->iterate_devices(ti, device_supports_poll, NULL))
+ return false;
+ }
+
+ return true;
+}
+
void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
struct queue_limits *limits)
{
@@ -1883,6 +1908,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
#endif
blk_queue_update_readahead(q);
+
+ if (dm_table_supports_poll(t))
+ blk_queue_flag_set(QUEUE_FLAG_POLL, q);
}
unsigned int dm_table_get_num_targets(struct dm_table *t)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 03c2b867acaa..ffd2c5ead256 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -3049,6 +3049,7 @@ static const struct pr_ops dm_pr_ops = {
};
static const struct block_device_operations dm_blk_dops = {
+ .iopoll = blk_bio_poll,
.submit_bio = dm_submit_bio,
.open = dm_blk_open,
.release = dm_blk_close,
--
2.27.0
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