Jens Axboe wrote:
> On Mon, Aug 22 2005, Douglas Gilbert wrote:
>
>> if (scsicmd[0] == READ_6 || scsicmd[0] == WRITE_6) {
>>- qc->nsect = tf->nsect = scsicmd[4];
>>+ if (scsicmd[4] == 0) {
>>+ /*
>>+ * For READ_6 and WRITE_6 (only)
>>+ * transfer_len==0 -> 256 blocks !!
>>+ */
>>+ if (lba48) {
>>+ tf->hob_nsect = 1;
>>+ qc->nsect = 256;
>>+ } else
>>+ return 1;
>
>
> This isn't quite right, for 28-bit lba a 0 sector value means 256
> sectors to transfer as well. So just make that:
>
> if (lba48) {
> tf->hob_nsect = 1;
> qc->nsect = 256;
> }
>
> /* continue */
>
> and it should work fine. Similarly for 48-bit lba, 0 means 16^2 sectors.
Jens,
Since for 28-bit lba a 0 sector value means 256 sectors
do I need to check for the lba48 case at all? As proposed
to Jeff is this ok (for READ_6 and WRITE_6):
if (scsicmd[4] == 0) {
/*
* For READ_6 and WRITE_6 (only)
* transfer_len==0 -> 256 blocks !!
*/
qc->nsect = 256;
} else
qc->nsect = scsicmd[4];
tf->nsect = scsicmd[4];
Also I noticed while testing the original code with READ_6
(sectors=0) that the device locked up (power cycle required).
So given the point you make for 48-bit lba, 0 means 16^2
sectors, then the READ_10 (sectors=0) and READ_16 (sectors=0)
which are valid nops according to SBC-2 may also lock up
in libata.
Doug Gilbert
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