[PATCH V2] SCSI: Add runtime pm in the sd_check_events()

[Lan Tianyu <tianyu.lan@xxxxxxxxx>]

The sd_check_event() will be called periodly even when the device is in
the suspended status to check media event. The scsi_test_unit_ready() in
the sd_check_event() will issue scsi cmd request. Issuing scsi request when
the device is in the suspeneded status will cause problem. For example, when
a usb flash disk in the suspended status, scsi_test_unit_ready() issues a
scsi request. The request will be returned as failed because the usb device
is not active. The patch adds scsi_autopm_get_device() and scsi_autopm_put_device()
around scsi_test_unit_ready() in the sd_check_event() to resolve such problem.

Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
 drivers/scsi/sd.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c691fb5..2d18aa9 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1182,9 +1182,14 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
 	retval = -ENODEV;
 
 	if (scsi_block_when_processing_errors(sdp)) {
+		retval = scsi_autopm_get_device(sdp);
+		if (retval)
+			goto out;
+
 		sshdr  = kzalloc(sizeof(*sshdr), GFP_KERNEL);
 		retval = scsi_test_unit_ready(sdp, SD_TIMEOUT, SD_MAX_RETRIES,
 					      sshdr);
+		scsi_autopm_put_device(sdp);
 	}
 
 	/* failed to execute TUR, assume media not present */
-- 
1.7.6.rc2.8.g28eb

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