See below. On 2019-01-15 7:50 p.m., Bart Van Assche wrote:
From: "Martin K. Petersen" <martin.peter...@oracle.com>Create a helper function for each of the 6, 10, 16 and 32-byte READ/WRITE variants and use those when setting up reads and writes. Reviewed-by: Hannes Reinecke <h...@suse.com> Signed-off-by: Martin K. Petersen <martin.peter...@oracle.com> [ bvanassche: ported this patch from kernel v4.11 to kernel v5.0 and made function names shorter. ] Signed-off-by: Bart Van Assche <bvanass...@acm.org> --- drivers/scsi/sd.c | 167 +++++++++++++++++++++++++--------------------- 1 file changed, 92 insertions(+), 75 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 13d2137b94b1..53093a34b1fc 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1072,6 +1072,83 @@ static blk_status_t sd_setup_flush_cmnd(struct scsi_cmnd *cmd) return BLK_STS_OK; }+static blk_status_t sd_setup_rw32_cmnd(struct scsi_cmnd *cmd, bool write,+ sector_t lba, unsigned int nr_blocks, + unsigned char flags) +{ + cmd->cmnd = mempool_alloc(sd_cdb_pool, GFP_ATOMIC); + if (unlikely(cmd->cmnd == NULL)) + return BLK_STS_RESOURCE; + + cmd->cmd_len = SD_EXT_CDB_SIZE; + memset(cmd->cmnd, 0, cmd->cmd_len); + + cmd->cmnd[0] = VARIABLE_LENGTH_CMD; + cmd->cmnd[7] = 0x18; /* Additional CDB len */ + cmd->cmnd[9] = write ? WRITE_32 : READ_32; + cmd->cmnd[10] = flags; + put_unaligned_be64(lba, &cmd->cmnd[12]); + put_unaligned_be32(lba, &cmd->cmnd[20]); /* Expected Indirect LBA */ + put_unaligned_be32(nr_blocks, &cmd->cmnd[28]); + + return BLK_STS_OK; +} + +static blk_status_t sd_setup_rw16_cmnd(struct scsi_cmnd *cmd, bool write, + sector_t lba, unsigned int nr_blocks, + unsigned char flags) +{ + cmd->cmd_len = 16; + cmd->cmnd[0] = write ? WRITE_16 : READ_16; + cmd->cmnd[1] = flags; + cmd->cmnd[14] = 0; + cmd->cmnd[15] = 0; + put_unaligned_be64(lba, &cmd->cmnd[2]); + put_unaligned_be32(nr_blocks, &cmd->cmnd[10]); + + return BLK_STS_OK; +} + +static blk_status_t sd_setup_rw10_cmnd(struct scsi_cmnd *cmd, bool write, + sector_t lba, unsigned int nr_blocks, + unsigned char flags) +{ + cmd->cmd_len = 10; + cmd->cmnd[0] = write ? WRITE_10 : READ_10; + cmd->cmnd[1] = flags; + cmd->cmnd[6] = 0; + cmd->cmnd[9] = 0; + put_unaligned_be32(lba, &cmd->cmnd[2]); + put_unaligned_be16(nr_blocks, &cmd->cmnd[7]); + + return BLK_STS_OK; +} + +static blk_status_t sd_setup_rw6_cmnd(struct scsi_cmnd *cmd, bool write, + sector_t lba, unsigned int nr_blocks, + unsigned char flags) +{ + if (unlikely(flags & 0x8)) { + /* + * This happens only if this drive failed 10byte rw + * command with ILLEGAL_REQUEST during operation and + * thus turned off use_10_for_rw. + */ + scmd_printk(KERN_ERR, cmd, "FUA write on READ/WRITE(6) drive\n"); + return BLK_STS_IOERR; + } + + cmd->cmd_len = 6; + cmd->cmnd[0] = write ? WRITE_6 : READ_6; + cmd->cmnd[1] = (lba >> 16) & 0x1f; + cmd->cmnd[2] = (lba >> 8) & 0xff; + cmd->cmnd[3] = lba & 0xff; + cmd->cmnd[4] = nr_blocks;
Since you have made this a separate function, observing the principle of least surprise, you may want to return an error if nr_blocks==0 since in that case the code as it stands will read or write 256 blocks! Otherwise it looks good and should be faster as bswap_16/32/64 should be faster than byte by byte shifts for the common case of big endian (SCSI) to little endian (most CPUs). Doug Gilbert
+ cmd->cmnd[5] = 0; + + return BLK_STS_OK; +} + static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt) { struct request *rq = SCpnt->request; @@ -1083,7 +1160,8 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt) unsigned int nr_blocks = sectors_to_logical(sdp, blk_rq_sectors(rq)); unsigned int dif, dix; unsigned int mask = logical_to_sectors(sdp, 1) - 1; - unsigned char protect; + bool write = rq_data_dir(rq) == WRITE; + unsigned char protect, fua; blk_status_t ret;ret = scsi_init_io(SCpnt);@@ -1158,6 +1236,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt) "writing" : "reading", nr_blocks, blk_rq_sectors(rq)));+ fua = rq->cmd_flags & REQ_FUA ? 0x8 : 0;dix = scsi_prot_sg_count(SCpnt); dif = scsi_host_dif_capable(SCpnt->device->host, sdkp->protection_type);@@ -1167,86 +1246,24 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)protect = 0;if (protect && sdkp->protection_type == T10_PI_TYPE2_PROTECTION) {- SCpnt->cmnd = mempool_alloc(sd_cdb_pool, GFP_ATOMIC); - - if (unlikely(!SCpnt->cmnd)) - return BLK_STS_RESOURCE; - - SCpnt->cmd_len = SD_EXT_CDB_SIZE; - memset(SCpnt->cmnd, 0, SCpnt->cmd_len); - SCpnt->cmnd[0] = VARIABLE_LENGTH_CMD; - SCpnt->cmnd[7] = 0x18; - SCpnt->cmnd[9] = (rq_data_dir(rq) == READ) ? READ_32 : WRITE_32; - SCpnt->cmnd[10] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 : 0); - - /* LBA */ - 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) (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) (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; + ret = sd_setup_rw32_cmnd(SCpnt, write, lba, nr_blocks, + protect | fua); } 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(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; + ret = sd_setup_rw16_cmnd(SCpnt, write, lba, nr_blocks, + protect | fua); } 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) (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) (nr_blocks >> 8) & 0xff; - SCpnt->cmnd[8] = (unsigned char) nr_blocks & 0xff; + ret = sd_setup_rw10_cmnd(SCpnt, write, lba, nr_blocks, + protect | fua); } else { - if (unlikely(rq->cmd_flags & REQ_FUA)) { - /* - * This happens only if this drive failed - * 10byte rw command with ILLEGAL_REQUEST - * during operation and thus turned off - * use_10_for_rw. - */ - scmd_printk(KERN_ERR, SCpnt, - "FUA write on READ/WRITE(6) drive\n"); - return BLK_STS_IOERR; - } - - 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; + ret = sd_setup_rw6_cmnd(SCpnt, write, lba, nr_blocks, + protect | fua); } + + if (unlikely(ret != BLK_STS_OK)) + return ret; + SCpnt->sdb.length = nr_blocks * sdp->sector_size;/*
