ata: libata-sata: Disallow changing LPM state if not supported

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>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20250701125321.69496-6-dlemoal@kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>

diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index cb46ce276bb119859aea71683e3b13e7cc7f5b06..47169c469f437bf29016e8e125e63f1146b5d070 100644 (file)
--- 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) {