Recently T10 standardized SBC constrained streams. This mechanism allows to pass data lifetime information to SCSI devices in the group number field. Add support for translating write hint information into a permanent stream number in the sd driver. Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Damien Le Moal <dlemoal@xxxxxxxxxx> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> --- drivers/scsi/sd.c | 104 +++++++++++++++++++++++++++++++++++++++++++++- drivers/scsi/sd.h | 2 + 2 files changed, 104 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 86b819fa04d9..48496e816409 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -47,6 +47,7 @@ #include <linux/blkpg.h> #include <linux/blk-pm.h> #include <linux/delay.h> +#include <linux/rw_hint.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/string_helpers.h> @@ -1080,12 +1081,35 @@ static blk_status_t sd_setup_flush_cmnd(struct scsi_cmnd *cmd) return BLK_STS_OK; } +/** + * sd_group_number() - Compute the GROUP NUMBER field + * @cmd: SCSI command for which to compute the value of the six-bit GROUP NUMBER + * field. + * + * From SBC-5 r05 (https://www.t10.org/cgi-bin/ac.pl?t=f&f=sbc5r05.pdf): + * 0: no relative lifetime. + * 1: shortest relative lifetime. + * 2: second shortest relative lifetime. + * 3 - 0x3d: intermediate relative lifetimes. + * 0x3e: second longest relative lifetime. + * 0x3f: longest relative lifetime. + */ +static u8 sd_group_number(struct scsi_cmnd *cmd) +{ + const struct request *rq = scsi_cmd_to_rq(cmd); + struct scsi_disk *sdkp = scsi_disk(rq->q->disk); + + return min3((u32)rq->write_hint, (u32)sdkp->permanent_stream_count, + 0x3fu); +} + static blk_status_t sd_setup_rw32_cmnd(struct scsi_cmnd *cmd, bool write, sector_t lba, unsigned int nr_blocks, unsigned char flags, unsigned int dld) { cmd->cmd_len = SD_EXT_CDB_SIZE; cmd->cmnd[0] = VARIABLE_LENGTH_CMD; + cmd->cmnd[6] = sd_group_number(cmd); cmd->cmnd[7] = 0x18; /* Additional CDB len */ cmd->cmnd[9] = write ? WRITE_32 : READ_32; cmd->cmnd[10] = flags; @@ -1104,7 +1128,7 @@ static blk_status_t sd_setup_rw16_cmnd(struct scsi_cmnd *cmd, bool write, cmd->cmd_len = 16; cmd->cmnd[0] = write ? WRITE_16 : READ_16; cmd->cmnd[1] = flags | ((dld >> 2) & 0x01); - cmd->cmnd[14] = (dld & 0x03) << 6; + cmd->cmnd[14] = ((dld & 0x03) << 6) | sd_group_number(cmd); cmd->cmnd[15] = 0; put_unaligned_be64(lba, &cmd->cmnd[2]); put_unaligned_be32(nr_blocks, &cmd->cmnd[10]); @@ -1119,7 +1143,7 @@ static blk_status_t sd_setup_rw10_cmnd(struct scsi_cmnd *cmd, bool write, cmd->cmd_len = 10; cmd->cmnd[0] = write ? WRITE_10 : READ_10; cmd->cmnd[1] = flags; - cmd->cmnd[6] = 0; + cmd->cmnd[6] = sd_group_number(cmd); cmd->cmnd[9] = 0; put_unaligned_be32(lba, &cmd->cmnd[2]); put_unaligned_be16(nr_blocks, &cmd->cmnd[7]); @@ -3001,6 +3025,81 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer) sdkp->DPOFUA = 0; } +static bool sd_is_perm_stream(struct scsi_disk *sdkp, unsigned int stream_id) +{ + u8 cdb[16] = { SERVICE_ACTION_IN_16, SAI_GET_STREAM_STATUS }; + struct { + struct scsi_stream_status_header h; + struct scsi_stream_status s; + } buf; + struct scsi_device *sdev = sdkp->device; + struct scsi_sense_hdr sshdr; + const struct scsi_exec_args exec_args = { + .sshdr = &sshdr, + }; + int res; + + put_unaligned_be16(stream_id, &cdb[4]); + put_unaligned_be32(sizeof(buf), &cdb[10]); + + res = scsi_execute_cmd(sdev, cdb, REQ_OP_DRV_IN, &buf, sizeof(buf), + SD_TIMEOUT, sdkp->max_retries, &exec_args); + if (res < 0) + return false; + if (scsi_status_is_check_condition(res) && scsi_sense_valid(&sshdr)) + sd_print_sense_hdr(sdkp, &sshdr); + if (res) + return false; + if (get_unaligned_be32(&buf.h.len) < sizeof(struct scsi_stream_status)) + return false; + return buf.h.stream_status[0].perm; +} + +static void sd_read_io_hints(struct scsi_disk *sdkp, unsigned char *buffer) +{ + struct scsi_device *sdp = sdkp->device; + const struct scsi_io_group_descriptor *desc, *start, *end; + struct scsi_sense_hdr sshdr; + struct scsi_mode_data data; + int res; + + if (!sdkp->rscs) + return; + + res = scsi_mode_sense(sdp, /*dbd=*/0x8, /*modepage=*/0x0a, + /*subpage=*/0x05, buffer, SD_BUF_SIZE, SD_TIMEOUT, + sdkp->max_retries, &data, &sshdr); + if (res < 0) + return; + start = (void *)buffer + data.header_length + 16; + end = (void *)buffer + ALIGN_DOWN(data.header_length + data.length, + sizeof(*end)); + /* + * From "SBC-5 Constrained Streams with Data Lifetimes": Device severs + * should assign the lowest numbered stream identifiers to permanent + * streams. + */ + for (desc = start; desc < end; desc++) + if (!desc->st_enble || !sd_is_perm_stream(sdkp, desc - start)) + break; + sdkp->permanent_stream_count = desc - start; + if (sdkp->permanent_stream_count < 2) { + sd_printk(KERN_INFO, sdkp, + "Unexpected: RSCS has been set and the permanent stream count is %u\n", + sdkp->permanent_stream_count); + return; + } + + sd_printk(KERN_INFO, sdkp, "permanent stream count = %d\n", + sdkp->permanent_stream_count); + /* + * Use WRITE(10) instead of WRITE(6) if data lifetime information is + * present because the WRITE(6) command does not have a GROUP NUMBER + * field. + */ + sdp->use_10_for_rw = true; +} + /* * The ATO bit indicates whether the DIF application tag is available * for use by the operating system. @@ -3481,6 +3580,7 @@ static int sd_revalidate_disk(struct gendisk *disk) sd_read_write_protect_flag(sdkp, buffer); sd_read_cache_type(sdkp, buffer); + sd_read_io_hints(sdkp, buffer); sd_read_app_tag_own(sdkp, buffer); sd_read_write_same(sdkp, buffer); sd_read_security(sdkp, buffer); diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h index f1120de03d51..5c4285a582b2 100644 --- a/drivers/scsi/sd.h +++ b/drivers/scsi/sd.h @@ -125,6 +125,8 @@ struct scsi_disk { unsigned int physical_block_size; unsigned int max_medium_access_timeouts; unsigned int medium_access_timed_out; + /* number of permanent streams */ + u16 permanent_stream_count; u8 media_present; u8 write_prot; u8 protection_type;/* Data Integrity Field */
