[PATCH v2 2/2] ata: libata-core: Allow capacity transition to zero for locked drives

[TJ Adams <tadamsjr@google.com>]

Commit 91842ed844a0 ("ata: libata-core: Set capacity to zero for a
security locked drive") introduced setting the device capacity (n_sectors)
to zero in ata_dev_configure() if the drive is security locked.

However, during runtime revalidation, ata_dev_revalidate() compares the
new capacity (now 0) with the old capacity (>0) and detects a mismatch.
Since it does not consider the locked status, it returns -ENODEV.

This revalidation failure can occur when doing a reset of the PHY (e.g.
hard reset) for a controller that has I/Os in flight. The timed out
I/Os trigger the SCSI Error Handling (EH) path, which in turn invokes
libata device revalidation. If the drive is locked at runtime (e.g.
it lost power during reset and relocked), revalidation sees the capacity
transition to zero and fails, eventually disabling the device.

Fix this by allowing the capacity transition to zero in
ata_dev_revalidate() if the drive is reported as security locked by
ata_id_is_locked().

Fixes: 91842ed844a0 ("ata: libata-core: Set capacity to zero for a security locked drive")
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Terrence Adams <tadamsjr@google.com>
---
 drivers/ata/libata-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3c06a15952f8..c43bd28b20b1 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -3992,7 +3992,7 @@ int ata_dev_revalidate(struct ata_device *dev, unsigned int new_class,
 
 	/* verify n_sectors hasn't changed */
 	if (dev->class != ATA_DEV_ATA || !n_sectors ||
-	    dev->n_sectors == n_sectors)
+	    dev->n_sectors == n_sectors || ata_id_is_locked(dev->id))
 		return 0;
 
 	/* n_sectors has changed */
-- 
2.55.0.rc2.803.g1fd1e6609c-goog