[PATCH 05/10] ata: libata-sata: Disallow changing LPM state if not supported

[Damien Le Moal <dlemoal@kernel.org>]

Modify ata_scsi_lpm_store() to return an error if a user attempts to set
a link power management policy for a port that does not support LPM,
that is, ports flagged with ATA_FLAG_NO_LPM.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/ata/libata-sata.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index cb46ce276bb1..47169c469f43 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -924,6 +924,11 @@ static ssize_t ata_scsi_lpm_store(struct device *device,
 
 	spin_lock_irqsave(ap->lock, flags);
 
+	if (ap->flags & ATA_FLAG_NO_LPM) {
+		count = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
 	ata_for_each_link(link, ap, EDGE) {
 		ata_for_each_dev(dev, &ap->link, ENABLED) {
 			if (dev->quirks & ATA_QUIRK_NOLPM) {
-- 
2.50.0