Re: [PATCH] scsi: sd: usb_storage: uas: Access media prior to querying device properties

On Tue, Feb 13, 2024 at 09:33:06AM -0500, Martin K. Petersen wrote:

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

...

+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);

+}

Do we still claim to support devices that implement only the 6-byte commands, not the 10-byte forms? Or is that now a non-issue?

Alan Stern