[035/165] libata: Use Maximum Write Same Length to report discard size

From: Greg KH
Date: Wed Jun 01 2011 - 04:59:18 EST

2.6.39-stable review patch. If anyone has any objections, please let us know.

Content-Length: 1118
Lines: 33

From: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>

commit 5f4e206666f834340b69ddb43f86de3851c8675a upstream.

Previously we used Maximum Unmap LBA Count in the Block Limits VPD to
signal the maximum number of sectors we could handle in a single Write
Same command.

Starting with SBC3r26 the Block Limits VPD has an explicit limit on the
number of blocks in a Write Same. This means we can stop abusing a field
related to the Unmap command and let our SAT use the proper value in the
VPD (Maximum Write Same Length).

Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Jeff Garzik <jgarzik@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/ata/libata-scsi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2139,7 +2139,7 @@ static unsigned int ata_scsiop_inq_b0(st
* with the unmap bit set.
if (ata_id_has_trim(args->id)) {
- put_unaligned_be32(65535 * 512 / 8, &rbuf[20]);
+ put_unaligned_be64(65535 * 512 / 8, &rbuf[36]);
put_unaligned_be32(1, &rbuf[28]);

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