[PATCH] USB: uas: Fix slave queue_depth not being set

Hans de Goede
2016-05-23T11:49:25Z

Commit 198de51dbc34 ("USB: uas: Limit qdepth at the scsi-host level")
removed the scsi_change_queue_depth() call from uas_slave_configure()
assuming that the slave would inherit the host's queue_depth, which
that commit sets to the same value.

This is incorrect, without the scsi_change_queue_depth() call the slave's
queue_depth defaults to 1, introducing a performance regression.

This commit restores the call, fixing the performance regression.

Cc: stable@vger.kernel.org
Fixes: 198de51dbc34 ("USB: uas: Limit qdepth at the scsi-host level")
Reported-by: Tom Yan <tom.ty89@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/usb/storage/uas.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 16bc679..ecc7d4b 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -835,6 +835,7 @@ static int uas_slave_configure(struct scsi_device *sdev)
if (devinfo->flags & US_FL_BROKEN_FUA)
sdev->broken_fua = 1;

+ scsi_change_queue_depth(sdev, devinfo->qdepth - 2);
return 0;
}

--
2.7.4