ata: libata-core: Do not try to set sleeping devices to standby

commit 4b08573 upstream.

In ata ata_dev_power_set_standby(), check that the target device is not
sleeping. If it is, there is no need to do anything.

Fixes: aa3998d ("ata: libata-scsi: Disable scsi device manage_system_start_stop")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/ata/libata-core.c

@@ -2034,6 +2034,10 @@ void ata_dev_power_set_active(struct ata_device *dev)
 	struct ata_taskfile tf;
 	unsigned int err_mask;
 
+	/* If the device is already sleeping, do nothing. */
+	if (dev->flags & ATA_DFLAG_SLEEPING)
+		return;
+
 	/*
 	 * Issue READ VERIFY SECTORS command for 1 sector at lba=0 only
 	 * if supported by the device.