libata: implement ATA_HORKAGE_MAX_TRIM_128M and apply to Sandisks

All three generations of Sandisk SSDs lock up hard intermittently.
Experiments showed that disabling NCQ lowered the failure rate significantly
and the kernel has been disabling NCQ for some models of SD7's and 8's,
which is obviously undesirable.

Karthik worked with Sandisk to root cause the hard lockups to trim commands
larger than 128M. This patch implements ATA_HORKAGE_MAX_TRIM_128M which
limits max trim size to 128M and applies it to all three generations of
Sandisk SSDs.

Signed-off-by: Tejun Heo <[e-mail]>
Cc: Karthik Shivaram <[e-mail]>
Cc: [e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

drivers/ata/libata-core.c

···
 	/* https://bugzilla.kernel.org/show_bug.cgi?id=15573 */
 	{ "C300-CTFDDAC128MAG",	"0001",		ATA_HORKAGE_NONCQ, },
 
-	/* Some Sandisk SSDs lock up hard with NCQ enabled.  Reported on
-	   SD7SN6S256G and SD8SN8U256G */
-	{ "SanDisk SD[78]SN*G",	NULL,		ATA_HORKAGE_NONCQ, },
+	/* Sandisk SD7/8/9s lock up hard on large trims */
+	{ "SanDisk SD[789]*",	NULL,		ATA_HORKAGE_MAX_TRIM_128M, },
 
 	/* devices which puke on READ_NATIVE_MAX */
 	{ "HDS724040KLSA80",	"KFAOA20N",	ATA_HORKAGE_BROKEN_HPA, },

drivers/ata/libata-scsi.c

···
 
 static unsigned int ata_scsiop_inq_b0(struct ata_scsi_args *args, u8 *rbuf)
 {
+	struct ata_device *dev = args->dev;
 	u16 min_io_sectors;
 
 	rbuf[1] = 0xb0;
···
 	 * with the unmap bit set.
 	 */
 	if (ata_id_has_trim(args->id)) {
-		put_unaligned_be64(65535 * ATA_MAX_TRIM_RNUM, &rbuf[36]);
+		u64 max_blocks = 65535 * ATA_MAX_TRIM_RNUM;
+
+		if (dev->horkage & ATA_HORKAGE_MAX_TRIM_128M)
+			max_blocks = 128 << (20 - SECTOR_SHIFT);
+
+		put_unaligned_be64(max_blocks, &rbuf[36]);
 		put_unaligned_be32(1, &rbuf[28]);
 	}
 

include/linux/libata.h

···
 	ATA_HORKAGE_NO_DMA_LOG	= (1 << 23),	/* don't use DMA for log read */
 	ATA_HORKAGE_NOTRIM	= (1 << 24),	/* don't use TRIM */
 	ATA_HORKAGE_MAX_SEC_1024 = (1 << 25),	/* Limit max sects to 1024 */
+	ATA_HORKAGE_MAX_TRIM_128M = (1 << 26),	/* Limit max trim size to 128M */
 
 	 /* DMA mask for user DMA control: User visible values; DO NOT
 	    renumber */