Prepare for improving SSD performance in the following patch, which
needs to read queue flag of QUEUE_FLAG_NONROT in IO path. So we have
to freeze queue before changing this flag in sd_revalidate_disk().
However, queue freezing becomes quite slow after the queue is registered
because RCU period is involved.
So delay registering queue after sd_revalidate_disk() is done for
avoiding slow queue freezing which will be added to sd_revalidate_disk()
in the following patch.
Cc: Sathya Prakash <sathya.prakash@xxxxxxxxxxxx>
Cc: Chaitra P B <chaitra.basappa@xxxxxxxxxxxx>
Cc: Suganath Prabu Subramani <suganath-prabu.subramani@xxxxxxxxxxxx>
Cc: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
Cc: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx>
Cc: Shivasharan S <shivasharan.srikanteshwara@xxxxxxxxxxxx>
Cc: Ewan D. Milne <emilne@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>,
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Bart Van Assche <bart.vanassche@xxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
drivers/scsi/sd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 03163ac5fe95..0744c34468e1 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3368,12 +3368,14 @@ static int sd_probe(struct device *dev)
}
blk_pm_runtime_init(sdp->request_queue, dev);
- device_add_disk(dev, gd, NULL);
+ device_add_disk_no_queue_reg(dev, gd);
if (sdkp->capacity)
sd_dif_config_host(sdkp);
sd_revalidate_disk(gd);
+ blk_register_queue(gd);
+
if (sdkp->security) {
sdkp->opal_dev = init_opal_dev(sdp, &sd_sec_submit);
if (sdkp->opal_dev)
--
2.20.1
