libata: implement ATA_HORKAGE_NO_NCQ_TRIM and apply it to Micro M500 SSDs

Certain drives cannot handle queued TRIM commands properly, even
though support is indicated in the IDENTIFY DEVICE buffer.  This patch
allows for disabling the commands for the affected drives and apply it
to the Micron/Crucial M500 SSDs which exhibit incorrect protocol
behavior when issued queued TRIM commands, which could lead to silent
data corruption.

tj: Merged two unnecessarily split patches and made minor edits
    including shortening horkage name.
Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/g/1387246554-7311-1-git-send-email-marc.ceeeee@gmail.com
Cc: stable@vger.kernel.org # 3.12+

drivers/ata/libata-core.c

@@ -2149,9 +2149,16 @@ static int ata_dev_config_ncq(struct ata_device *dev,
 				    "failed to get NCQ Send/Recv Log Emask 0x%x\n",
 				    err_mask);
 		} else {
+			u8 *cmds = dev->ncq_send_recv_cmds;
+
 			dev->flags |= ATA_DFLAG_NCQ_SEND_RECV;
-			memcpy(dev->ncq_send_recv_cmds, ap->sector_buf,
-				ATA_LOG_NCQ_SEND_RECV_SIZE);
+			memcpy(cmds, ap->sector_buf, ATA_LOG_NCQ_SEND_RECV_SIZE);
+
+			if (dev->horkage & ATA_HORKAGE_NO_NCQ_TRIM) {
+				ata_dev_dbg(dev, "disabling queued TRIM support\n");
+				cmds[ATA_LOG_NCQ_SEND_RECV_DSM_OFFSET] &=
+					~ATA_LOG_NCQ_SEND_RECV_DSM_TRIM;
+			}
 		}
 	}
 
@@ -4205,6 +4212,10 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
 	{ "PIONEER DVD-RW  DVR-212D",	NULL,	ATA_HORKAGE_NOSETXFER },
 	{ "PIONEER DVD-RW  DVR-216D",	NULL,	ATA_HORKAGE_NOSETXFER },
 
+	/* devices that don't properly handle queued TRIM commands */
+	{ "Micron_M500*",		NULL,	ATA_HORKAGE_NO_NCQ_TRIM, },
+	{ "Crucial_CT???M500SSD1",	NULL,	ATA_HORKAGE_NO_NCQ_TRIM, },
+
 	/* End Marker */
 	{ }
 };

include/linux/libata.h

@@ -418,6 +418,7 @@ enum {
 	ATA_HORKAGE_DUMP_ID	= (1 << 16),	/* dump IDENTIFY data */
 	ATA_HORKAGE_MAX_SEC_LBA48 = (1 << 17),	/* Set max sects to 65535 */
 	ATA_HORKAGE_ATAPI_DMADIR = (1 << 18),	/* device requires dmadir */
+	ATA_HORKAGE_NO_NCQ_TRIM	= (1 << 19),	/* don't use queued TRIM */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */