scsi: sd: Be consistent about blocks vs. sectors

We have had several bugs due mixing sector and logical block size
terminology. In the block layer, a sector is a 512-byte unit regardless of
the logical block size of the underlying device. But the term "sector" is
still widely used in sd.c when referring to logical block sized units.

We previously introduced helper functions such as sectors_to_logical() and
logical_to_sectors() to make the distinction clear. Use these to make the
code in sd.c consistent wrt. logical blocks and block layer sectors.

Use "lba" to describe a logical block address and "nr_blocks" when counting
logical blocks. SBC uses "TRANSFER LENGTH" to describe the latter but this
term was avoided to prevent confusion with the very similar DMA transfer
size (->transfersize) which is counted in bytes.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
[ bvanassche: ported this patch from kernel v4.11 to kernel v5.0 ]
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 83 insertions, 86 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index a60b98681f15..4d14208fe6db 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -817,8 +817,8 @@ static blk_status_t sd_setup_unmap_cmnd(struct scsi_cmnd *cmd)
 {
 	struct scsi_device *sdp = cmd->device;
 	struct request *rq = cmd->request;
-	u64 sector = blk_rq_pos(rq) >> (ilog2(sdp->sector_size) - 9);
-	u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
+	u64 lba = sectors_to_logical(sdp, blk_rq_pos(rq));
+	u32 nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
 	unsigned int data_len = 24;
 	char *buf;
 
@@ -837,8 +837,8 @@ static blk_status_t sd_setup_unmap_cmnd(struct scsi_cmnd *cmd)
 	buf = page_address(rq->special_vec.bv_page);
 	put_unaligned_be16(6 + 16, &buf[0]);
 	put_unaligned_be16(16, &buf[2]);
-	put_unaligned_be64(sector, &buf[8]);
-	put_unaligned_be32(nr_sectors, &buf[16]);
+	put_unaligned_be64(lba, &buf[8]);
+	put_unaligned_be32(nr_blocks, &buf[16]);
 
 	cmd->allowed = SD_MAX_RETRIES;
 	cmd->transfersize = data_len;
@@ -853,8 +853,8 @@ static blk_status_t sd_setup_write_same16_cmnd(struct scsi_cmnd *cmd,
 {
 	struct scsi_device *sdp = cmd->device;
 	struct request *rq = cmd->request;
-	u64 sector = blk_rq_pos(rq) >> (ilog2(sdp->sector_size) - 9);
-	u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
+	u64 lba = sectors_to_logical(sdp, blk_rq_pos(rq));
+	u32 nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
 	u32 data_len = sdp->sector_size;
 
 	rq->special_vec.bv_page = mempool_alloc(sd_page_pool, GFP_ATOMIC);
@@ -869,8 +869,8 @@ static blk_status_t sd_setup_write_same16_cmnd(struct scsi_cmnd *cmd,
 	cmd->cmnd[0] = WRITE_SAME_16;
 	if (unmap)
 		cmd->cmnd[1] = 0x8; /* UNMAP */
-	put_unaligned_be64(sector, &cmd->cmnd[2]);
-	put_unaligned_be32(nr_sectors, &cmd->cmnd[10]);
+	put_unaligned_be64(lba, &cmd->cmnd[2]);
+	put_unaligned_be32(nr_blocks, &cmd->cmnd[10]);
 
 	cmd->allowed = SD_MAX_RETRIES;
 	cmd->transfersize = data_len;
@@ -885,8 +885,8 @@ static blk_status_t sd_setup_write_same10_cmnd(struct scsi_cmnd *cmd,
 {
 	struct scsi_device *sdp = cmd->device;
 	struct request *rq = cmd->request;
-	u64 sector = blk_rq_pos(rq) >> (ilog2(sdp->sector_size) - 9);
-	u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
+	u64 lba = sectors_to_logical(sdp, blk_rq_pos(rq));
+	u32 nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
 	u32 data_len = sdp->sector_size;
 
 	rq->special_vec.bv_page = mempool_alloc(sd_page_pool, GFP_ATOMIC);
@@ -901,8 +901,8 @@ static blk_status_t sd_setup_write_same10_cmnd(struct scsi_cmnd *cmd,
 	cmd->cmnd[0] = WRITE_SAME;
 	if (unmap)
 		cmd->cmnd[1] = 0x8; /* UNMAP */
-	put_unaligned_be32(sector, &cmd->cmnd[2]);
-	put_unaligned_be16(nr_sectors, &cmd->cmnd[7]);
+	put_unaligned_be32(lba, &cmd->cmnd[2]);
+	put_unaligned_be16(nr_blocks, &cmd->cmnd[7]);
 
 	cmd->allowed = SD_MAX_RETRIES;
 	cmd->transfersize = data_len;
@@ -917,8 +917,8 @@ static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
 	struct request *rq = cmd->request;
 	struct scsi_device *sdp = cmd->device;
 	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
-	u64 sector = blk_rq_pos(rq) >> (ilog2(sdp->sector_size) - 9);
-	u32 nr_sectors = blk_rq_sectors(rq) >> (ilog2(sdp->sector_size) - 9);
+	u64 lba = sectors_to_logical(sdp, blk_rq_pos(rq));
+	u32 nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
 
 	if (!(rq->cmd_flags & REQ_NOUNMAP)) {
 		switch (sdkp->zeroing_mode) {
@@ -932,7 +932,7 @@ static blk_status_t sd_setup_write_zeroes_cmnd(struct scsi_cmnd *cmd)
 	if (sdp->no_write_same)
 		return BLK_STS_TARGET;
 
-	if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff)
+	if (sdkp->ws16 || lba > 0xffffffff || nr_blocks > 0xffff)
 		return sd_setup_write_same16_cmnd(cmd, false);
 
 	return sd_setup_write_same10_cmnd(cmd, false);
@@ -1013,8 +1013,8 @@ static blk_status_t sd_setup_write_same_cmnd(struct scsi_cmnd *cmd)
 	struct scsi_device *sdp = cmd->device;
 	struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
 	struct bio *bio = rq->bio;
-	sector_t sector = blk_rq_pos(rq);
-	unsigned int nr_sectors = blk_rq_sectors(rq);
+	u64 lba = sectors_to_logical(sdp, blk_rq_pos(rq));
+	u32 nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq));
 	blk_status_t ret;
 
 	if (sdkp->device->no_write_same)
@@ -1022,21 +1022,18 @@ static blk_status_t sd_setup_write_same_cmnd(struct scsi_cmnd *cmd)
 
 	BUG_ON(bio_offset(bio) || bio_iovec(bio).bv_len != sdp->sector_size);
 
-	sector >>= ilog2(sdp->sector_size) - 9;
-	nr_sectors >>= ilog2(sdp->sector_size) - 9;
-
 	rq->timeout = SD_WRITE_SAME_TIMEOUT;
 
-	if (sdkp->ws16 || sector > 0xffffffff || nr_sectors > 0xffff) {
+	if (sdkp->ws16 || lba > 0xffffffff || nr_blocks > 0xffff) {
 		cmd->cmd_len = 16;
 		cmd->cmnd[0] = WRITE_SAME_16;
-		put_unaligned_be64(sector, &cmd->cmnd[2]);
-		put_unaligned_be32(nr_sectors, &cmd->cmnd[10]);
+		put_unaligned_be64(lba, &cmd->cmnd[2]);
+		put_unaligned_be32(nr_blocks, &cmd->cmnd[10]);
 	} else {
 		cmd->cmd_len = 10;
 		cmd->cmnd[0] = WRITE_SAME;
-		put_unaligned_be32(sector, &cmd->cmnd[2]);
-		put_unaligned_be16(nr_sectors, &cmd->cmnd[7]);
+		put_unaligned_be32(lba, &cmd->cmnd[2]);
+		put_unaligned_be16(nr_blocks, &cmd->cmnd[7]);
 	}
 
 	cmd->transfersize = sdp->sector_size;
@@ -1081,9 +1078,9 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	struct scsi_device *sdp = SCpnt->device;
 	struct gendisk *disk = rq->rq_disk;
 	struct scsi_disk *sdkp = scsi_disk(disk);
-	sector_t block = blk_rq_pos(rq);
+	sector_t lba = blk_rq_pos(rq);
 	sector_t threshold;
-	unsigned int this_count = blk_rq_sectors(rq);
+	unsigned int nr_blocks = blk_rq_sectors(rq);
 	unsigned int dif, dix;
 	unsigned char protect;
 	blk_status_t ret;
@@ -1096,10 +1093,10 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	SCSI_LOG_HLQUEUE(1,
 		scmd_printk(KERN_INFO, SCpnt,
 			"%s: block=%llu, count=%d\n",
-			__func__, (unsigned long long)block, this_count));
+			__func__, (unsigned long long)lba, nr_blocks));
 
 	if (!sdp || !scsi_device_online(sdp) ||
-	    block + blk_rq_sectors(rq) > get_capacity(disk)) {
+	    lba + blk_rq_sectors(rq) > get_capacity(disk)) {
 		SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
 						"Finishing %u sectors\n",
 						blk_rq_sectors(rq)));
@@ -1124,18 +1121,18 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	threshold = get_capacity(disk) - SD_LAST_BUGGY_SECTORS *
 		(sdp->sector_size / 512);
 
-	if (unlikely(sdp->last_sector_bug && block + this_count > threshold)) {
-		if (block < threshold) {
+	if (unlikely(sdp->last_sector_bug && lba + nr_blocks > threshold)) {
+		if (lba < threshold) {
 			/* Access up to the threshold but not beyond */
-			this_count = threshold - block;
+			nr_blocks = threshold - lba;
 		} else {
 			/* Access only a single hardware sector */
-			this_count = sdp->sector_size / 512;
+			nr_blocks = sdp->sector_size / 512;
 		}
 	}
 
 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu\n",
-					(unsigned long long)block));
+					(unsigned long long)lba));
 
 	/*
 	 * If we have a 1K hardware sectorsize, prevent access to single
@@ -1149,31 +1146,31 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	 * for this.
 	 */
 	if (sdp->sector_size == 1024) {
-		if ((block & 1) || (blk_rq_sectors(rq) & 1)) {
+		if ((lba & 1) || (blk_rq_sectors(rq) & 1)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				    "Bad block number requested\n");
 			return BLK_STS_IOERR;
 		}
-		block = block >> 1;
-		this_count = this_count >> 1;
+		lba = lba >> 1;
+		nr_blocks = nr_blocks >> 1;
 	}
 	if (sdp->sector_size == 2048) {
-		if ((block & 3) || (blk_rq_sectors(rq) & 3)) {
+		if ((lba & 3) || (blk_rq_sectors(rq) & 3)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				    "Bad block number requested\n");
 			return BLK_STS_IOERR;
 		}
-		block = block >> 2;
-		this_count = this_count >> 2;
+		lba = lba >> 2;
+		nr_blocks = nr_blocks >> 2;
 	}
 	if (sdp->sector_size == 4096) {
-		if ((block & 7) || (blk_rq_sectors(rq) & 7)) {
+		if ((lba & 7) || (blk_rq_sectors(rq) & 7)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				    "Bad block number requested\n");
 			return BLK_STS_IOERR;
 		}
-		block = block >> 3;
-		this_count = this_count >> 3;
+		lba = lba >> 3;
+		nr_blocks = nr_blocks >> 3;
 	}
 	if (rq_data_dir(rq) == WRITE) {
 		SCpnt->cmnd[0] = WRITE_6;
@@ -1191,7 +1188,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt,
 					"%s %d/%u 512 byte blocks.\n",
 					(rq_data_dir(rq) == WRITE) ?
-					"writing" : "reading", this_count,
+					"writing" : "reading", nr_blocks,
 					blk_rq_sectors(rq)));
 
 	dix = scsi_prot_sg_count(SCpnt);
@@ -1216,54 +1213,54 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 		SCpnt->cmnd[10] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);
 
 		/* LBA */
-		SCpnt->cmnd[12] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
-		SCpnt->cmnd[13] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
-		SCpnt->cmnd[14] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
-		SCpnt->cmnd[15] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
-		SCpnt->cmnd[16] = (unsigned char) (block >> 24) & 0xff;
-		SCpnt->cmnd[17] = (unsigned char) (block >> 16) & 0xff;
-		SCpnt->cmnd[18] = (unsigned char) (block >> 8) & 0xff;
-		SCpnt->cmnd[19] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[12] = sizeof(lba) > 4 ? (unsigned char) (lba >> 56) & 0xff : 0;
+		SCpnt->cmnd[13] = sizeof(lba) > 4 ? (unsigned char) (lba >> 48) & 0xff : 0;
+		SCpnt->cmnd[14] = sizeof(lba) > 4 ? (unsigned char) (lba >> 40) & 0xff : 0;
+		SCpnt->cmnd[15] = sizeof(lba) > 4 ? (unsigned char) (lba >> 32) & 0xff : 0;
+		SCpnt->cmnd[16] = (unsigned char) (lba >> 24) & 0xff;
+		SCpnt->cmnd[17] = (unsigned char) (lba >> 16) & 0xff;
+		SCpnt->cmnd[18] = (unsigned char) (lba >> 8) & 0xff;
+		SCpnt->cmnd[19] = (unsigned char) lba & 0xff;
 
 		/* Expected Indirect LBA */
-		SCpnt->cmnd[20] = (unsigned char) (block >> 24) & 0xff;
-		SCpnt->cmnd[21] = (unsigned char) (block >> 16) & 0xff;
-		SCpnt->cmnd[22] = (unsigned char) (block >> 8) & 0xff;
-		SCpnt->cmnd[23] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[20] = (unsigned char) (lba >> 24) & 0xff;
+		SCpnt->cmnd[21] = (unsigned char) (lba >> 16) & 0xff;
+		SCpnt->cmnd[22] = (unsigned char) (lba >> 8) & 0xff;
+		SCpnt->cmnd[23] = (unsigned char) lba & 0xff;
 
 		/* Transfer length */
-		SCpnt->cmnd[28] = (unsigned char) (this_count >> 24) & 0xff;
-		SCpnt->cmnd[29] = (unsigned char) (this_count >> 16) & 0xff;
-		SCpnt->cmnd[30] = (unsigned char) (this_count >> 8) & 0xff;
-		SCpnt->cmnd[31] = (unsigned char) this_count & 0xff;
-	} else if (sdp->use_16_for_rw || (this_count > 0xffff)) {
+		SCpnt->cmnd[28] = (unsigned char) (nr_blocks >> 24) & 0xff;
+		SCpnt->cmnd[29] = (unsigned char) (nr_blocks >> 16) & 0xff;
+		SCpnt->cmnd[30] = (unsigned char) (nr_blocks >> 8) & 0xff;
+		SCpnt->cmnd[31] = (unsigned char) nr_blocks & 0xff;
+	} else if (sdp->use_16_for_rw || (nr_blocks > 0xffff)) {
 		SCpnt->cmnd[0] += READ_16 - READ_6;
 		SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);
-		SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
-		SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
-		SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
-		SCpnt->cmnd[5] = sizeof(block) > 4 ? (unsigned char) (block >> 32) & 0xff : 0;
-		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
-		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
-		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
-		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
-		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
-		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
-		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
-		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
+		SCpnt->cmnd[2] = sizeof(lba) > 4 ? (unsigned char) (lba >> 56) & 0xff : 0;
+		SCpnt->cmnd[3] = sizeof(lba) > 4 ? (unsigned char) (lba >> 48) & 0xff : 0;
+		SCpnt->cmnd[4] = sizeof(lba) > 4 ? (unsigned char) (lba >> 40) & 0xff : 0;
+		SCpnt->cmnd[5] = sizeof(lba) > 4 ? (unsigned char) (lba >> 32) & 0xff : 0;
+		SCpnt->cmnd[6] = (unsigned char) (lba >> 24) & 0xff;
+		SCpnt->cmnd[7] = (unsigned char) (lba >> 16) & 0xff;
+		SCpnt->cmnd[8] = (unsigned char) (lba >> 8) & 0xff;
+		SCpnt->cmnd[9] = (unsigned char) lba & 0xff;
+		SCpnt->cmnd[10] = (unsigned char) (nr_blocks >> 24) & 0xff;
+		SCpnt->cmnd[11] = (unsigned char) (nr_blocks >> 16) & 0xff;
+		SCpnt->cmnd[12] = (unsigned char) (nr_blocks >> 8) & 0xff;
+		SCpnt->cmnd[13] = (unsigned char) nr_blocks & 0xff;
 		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
-	} else if ((this_count > 0xff) || (block > 0x1fffff) ||
+	} else if ((nr_blocks > 0xff) || (lba > 0x1fffff) ||
 		   scsi_device_protection(SCpnt->device) ||
 		   SCpnt->device->use_10_for_rw) {
 		SCpnt->cmnd[0] += READ_10 - READ_6;
 		SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0);
-		SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
-		SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
-		SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
-		SCpnt->cmnd[5] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[2] = (unsigned char) (lba >> 24) & 0xff;
+		SCpnt->cmnd[3] = (unsigned char) (lba >> 16) & 0xff;
+		SCpnt->cmnd[4] = (unsigned char) (lba >> 8) & 0xff;
+		SCpnt->cmnd[5] = (unsigned char) lba & 0xff;
 		SCpnt->cmnd[6] = SCpnt->cmnd[9] = 0;
-		SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
-		SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
+		SCpnt->cmnd[7] = (unsigned char) (nr_blocks >> 8) & 0xff;
+		SCpnt->cmnd[8] = (unsigned char) nr_blocks & 0xff;
 	} else {
 		if (unlikely(rq->cmd_flags & REQ_FUA)) {
 			/*
@@ -1277,13 +1274,13 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 			return BLK_STS_IOERR;
 		}
 
-		SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
-		SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
-		SCpnt->cmnd[3] = (unsigned char) block & 0xff;
-		SCpnt->cmnd[4] = (unsigned char) this_count;
+		SCpnt->cmnd[1] |= (unsigned char) ((lba >> 16) & 0x1f);
+		SCpnt->cmnd[2] = (unsigned char) ((lba >> 8) & 0xff);
+		SCpnt->cmnd[3] = (unsigned char) lba & 0xff;
+		SCpnt->cmnd[4] = (unsigned char) nr_blocks;
 		SCpnt->cmnd[5] = 0;
 	}
-	SCpnt->sdb.length = this_count * sdp->sector_size;
+	SCpnt->sdb.length = nr_blocks * sdp->sector_size;
 
 	/*
 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
@@ -1291,7 +1288,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
 	 * this many bytes between each connect / disconnect.
 	 */
 	SCpnt->transfersize = sdp->sector_size;
-	SCpnt->underflow = this_count << 9;
+	SCpnt->underflow = nr_blocks << 9;
 	SCpnt->allowed = SD_MAX_RETRIES;
 
 	/*