scsi: sd: usb_storage: uas: Access media prior to querying device properties

commit 321da3dc1f3c92a12e3c5da934090d2992a8814c upstream.

It has been observed that some USB/UAS devices return generic properties
hardcoded in firmware for mode pages for a period of time after a device
has been discovered. The reported properties are either garbage or they do
not accurately reflect the characteristics of the physical storage device
attached in the case of a bridge.

Prior to commit 1e029397d12f ("scsi: sd: Reorganize DIF/DIX code to
avoid calling revalidate twice") we would call revalidate several
times during device discovery. As a result, incorrect values would
eventually get replaced with ones accurately describing the attached
storage. When we did away with the redundant revalidate pass, several
cases were reported where devices reported nonsensical values or would
end up in write-protected state.

An initial attempt at addressing this issue involved introducing a
delayed second revalidate invocation. However, this approach still
left some devices reporting incorrect characteristics.

Tasos Sahanidis debugged the problem further and identified that
introducing a READ operation prior to MODE SENSE fixed the problem and that
it wasn't a timing issue. Issuing a READ appears to cause the devices to
update their state to reflect the actual properties of the storage
media. Device properties like vendor, model, and storage capacity appear to
be correctly reported from the get-go. It is unclear why these devices
defer populating the remaining characteristics.

Match the behavior of a well known commercial operating system and
trigger a READ operation prior to querying device characteristics to
force the device to populate the mode pages.

The additional READ is triggered by a flag set in the USB storage and
UAS drivers. We avoid issuing the READ for other transport classes
since some storage devices identify Linux through our particular
discovery command sequence.

Link: https://lore.kernel.org/r/20240213143306.2194237-1-martin.petersen@oracle.com
Fixes: 1e029397d12f ("scsi: sd: Reorganize DIF/DIX code to avoid calling revalidate twice")
Cc: stable@vger.kernel.org
Reported-by: Tasos Sahanidis <tasos@tasossah.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Tasos Sahanidis <tasos@tasossah.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 25 insertions, 1 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c2e8d9e27749..1335119a4993 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3404,6 +3404,24 @@ static bool sd_validate_opt_xfer_size(struct scsi_disk *sdkp,
 	return true;
 }
 
+static void sd_read_block_zero(struct scsi_disk *sdkp)
+{
+	unsigned int buf_len = sdkp->device->sector_size;
+	char *buffer, cmd[10] = { };
+
+	buffer = kmalloc(buf_len, GFP_KERNEL);
+	if (!buffer)
+		return;
+
+	cmd[0] = READ_10;
+	put_unaligned_be32(0, &cmd[2]); /* Logical block address 0 */
+	put_unaligned_be16(1, &cmd[7]);	/* Transfer 1 logical block */
+
+	scsi_execute_cmd(sdkp->device, cmd, REQ_OP_DRV_IN, buffer, buf_len,
+			 SD_TIMEOUT, sdkp->max_retries, NULL);
+	kfree(buffer);
+}
+
 /**
  *	sd_revalidate_disk - called the first time a new disk is seen,
  *	performs disk spin up, read_capacity, etc.
@@ -3443,7 +3461,13 @@ static int sd_revalidate_disk(struct gendisk *disk)
 	 */
 	if (sdkp->media_present) {
 		sd_read_capacity(sdkp, buffer);
-
+		/*
+		 * Some USB/UAS devices return generic values for mode pages
+		 * until the media has been accessed. Trigger a READ operation
+		 * to force the device to populate mode pages.
+		 */
+		if (sdp->read_before_ms)
+			sd_read_block_zero(sdkp);
 		/*
 		 * set the default to rotational.  All non-rotational devices
 		 * support the block characteristics VPD page, which will