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Commit c6a33e24 authored by Albert Lee's avatar Albert Lee Committed by Jeff Garzik
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[PATCH] libata CHS: LBA28/LBA48 optimization (revise #6) 



     - add lba_28_ok() and lba_48_ok() to ata.h.
     - check ending block number instead of staring block number.
     - use lba_28_ok() for CHS range check
     - LBA28/LBA48 optimization

Suggested by Mark Lord and Alan Cox.

Signed-off-by: default avatarAlbert Lee <albertcc@tw.ibm.com>

=====
Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
parent 59a10b17

drivers/scsi/libata-scsi.c

+21 −27
Original line number Diff line number Diff line
@@ -636,9 +636,13 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd) 
	if (dev->flags & ATA_DFLAG_LBA) {

		tf->flags |= ATA_TFLAG_LBA;



		if (dev->flags & ATA_DFLAG_LBA48) {

			if (n_block > (64 * 1024))

				goto invalid_fld;

		if (lba_28_ok(block, n_block)) {

			/* use LBA28 */

			tf->command = ATA_CMD_VERIFY;

			tf->device |= (block >> 24) & 0xf;

		} else if (lba_48_ok(block, n_block)) {

			if (!(dev->flags & ATA_DFLAG_LBA48))

				goto out_of_range;



			/* use LBA48 */

			tf->flags |= ATA_TFLAG_LBA48;
@@ -649,15 +653,9 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd) 
			tf->hob_lbah = (block >> 40) & 0xff;

			tf->hob_lbam = (block >> 32) & 0xff;

			tf->hob_lbal = (block >> 24) & 0xff;

		} else {

			if (n_block > 256)

				goto invalid_fld;



			/* use LBA28 */

			tf->command = ATA_CMD_VERIFY;



			tf->device |= (block >> 24) & 0xf;

		}

		} else

			/* request too large even for LBA48 */

			goto out_of_range;



		tf->nsect = n_block & 0xff;
@@ -670,8 +668,8 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc, u8 *scsicmd) 
		/* CHS */

		u32 sect, head, cyl, track;



		if (n_block > 256)

			goto invalid_fld;

		if (!lba_28_ok(block, n_block))

			goto out_of_range;



		/* Convert LBA to CHS */

		track = (u32)block / dev->sectors;
@@ -784,9 +782,11 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd) 
	if (dev->flags & ATA_DFLAG_LBA) {

		tf->flags |= ATA_TFLAG_LBA;



		if (dev->flags & ATA_DFLAG_LBA48) {

			/* The request -may- be too large for LBA48. */

			if ((block >> 48) || (n_block > 65536))

		if (lba_28_ok(block, n_block)) {

			/* use LBA28 */

			tf->device |= (block >> 24) & 0xf;

		} else if (lba_48_ok(block, n_block)) {

			if (!(dev->flags & ATA_DFLAG_LBA48))

				goto out_of_range;



			/* use LBA48 */
@@ -797,16 +797,10 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd) 
			tf->hob_lbah = (block >> 40) & 0xff;

			tf->hob_lbam = (block >> 32) & 0xff;

			tf->hob_lbal = (block >> 24) & 0xff;

		} else { 

			/* use LBA28 */



			/* The request -may- be too large for LBA28. */

			if ((block >> 28) || (n_block > 256))

		} else

			/* request too large even for LBA48 */

			goto out_of_range;



			tf->device |= (block >> 24) & 0xf;

		}



		ata_rwcmd_protocol(qc);



		qc->nsect = n_block;
@@ -822,7 +816,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc, u8 *scsicmd) 
		u32 sect, head, cyl, track;



		/* The request -may- be too large for CHS addressing. */

		if ((block >> 28) || (n_block > 256))

		if (!lba_28_ok(block, n_block))

			goto out_of_range;



		ata_rwcmd_protocol(qc);

include/linux/ata.h

+12 −0
Original line number Diff line number Diff line
@@ -291,4 +291,16 @@ static inline int ata_ok(u8 status) 
			== ATA_DRDY);

}



static inline int lba_28_ok(u64 block, u32 n_block)

{

	/* check the ending block number */

	return ((block + n_block - 1) < ((u64)1 << 28)) && (n_block <= 256);

}



static inline int lba_48_ok(u64 block, u32 n_block)

{

	/* check the ending block number */

	return ((block + n_block - 1) < ((u64)1 << 48)) && (n_block <= 65536);

}



#endif /* __LINUX_ATA_H__ */