libata bugfix: HDIO_DRIVE_TASK

I was trying to use HDIO_DRIVE_TASK for something today, and discovered that the libata implementation does not copy over the upper four LBA bits from args[6].

This is serious, as any tools using this ioctl would have their commands applied to the wrong sectors on the drive, possibly resulting in disk corruption.

Ideally, newer apps should use SG_IO/ATA_16 directly, avoiding this bug. But with libata poised to displace drivers/ide, better compatibility here is a must.

This patch fixes libata to use the upper four LBA bits passed in from the ioctl.

The original drivers/ide implementation copies over all bits except for the master/slave select bit. With this patch, libata will copy only the four high-order LBA bits, just in case there are assumptions elsewhere in libata (?).

---

@@ -295,6 +295,7 @@

	scsi_cmd[8]  = args[3];
	scsi_cmd[10] = args[4];
	scsi_cmd[12] = args[5];
+	scsi_cmd[13] = args[6] & 0x0f;
	scsi_cmd[14] = args[0];

	/* Good values for timeout and retries?  Values below

applied