From 6a7b43985daa4f42b6d6f0186594c3a68f84a1d8 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 28 Jun 2014 12:35:13 +0200 Subject: [PATCH] sd: don't use scsi_setup_blk_pc_cmnd for discard requests Simplify handling of discard requests by setting up the command directly instead of initializing request fields and then calling scsi_setup_blk_pc_cmnd to propagate the information into the command. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Reviewed-by: Hannes Reinecke --- drivers/scsi/sd.c | 50 +++++++++++++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 19 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index aefedf4fbb2b..03bed86b9fc9 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -691,8 +691,10 @@ static void sd_config_discard(struct scsi_disk *sdkp, unsigned int mode) * Will issue either UNMAP or WRITE SAME(16) depending on preference * indicated by target device. **/ -static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq) +static int sd_setup_discard_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); sector_t sector = blk_rq_pos(rq); unsigned int nr_sectors = blk_rq_sectors(rq); @@ -704,9 +706,6 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq) sector >>= ilog2(sdp->sector_size) - 9; nr_sectors >>= ilog2(sdp->sector_size) - 9; - rq->timeout = SD_TIMEOUT; - - memset(rq->cmd, 0, rq->cmd_len); page = alloc_page(GFP_ATOMIC | __GFP_ZERO); if (!page) @@ -716,9 +715,9 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq) case SD_LBP_UNMAP: buf = page_address(page); - rq->cmd_len = 10; - rq->cmd[0] = UNMAP; - rq->cmd[8] = 24; + cmd->cmd_len = 10; + cmd->cmnd[0] = UNMAP; + cmd->cmnd[8] = 24; put_unaligned_be16(6 + 16, &buf[0]); put_unaligned_be16(16, &buf[2]); @@ -729,23 +728,23 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq) break; case SD_LBP_WS16: - rq->cmd_len = 16; - rq->cmd[0] = WRITE_SAME_16; - rq->cmd[1] = 0x8; /* UNMAP */ - put_unaligned_be64(sector, &rq->cmd[2]); - put_unaligned_be32(nr_sectors, &rq->cmd[10]); + cmd->cmd_len = 16; + cmd->cmnd[0] = WRITE_SAME_16; + cmd->cmnd[1] = 0x8; /* UNMAP */ + put_unaligned_be64(sector, &cmd->cmnd[2]); + put_unaligned_be32(nr_sectors, &cmd->cmnd[10]); len = sdkp->device->sector_size; break; case SD_LBP_WS10: case SD_LBP_ZERO: - rq->cmd_len = 10; - rq->cmd[0] = WRITE_SAME; + cmd->cmd_len = 10; + cmd->cmnd[0] = WRITE_SAME; if (sdkp->provisioning_mode == SD_LBP_WS10) - rq->cmd[1] = 0x8; /* UNMAP */ - put_unaligned_be32(sector, &rq->cmd[2]); - put_unaligned_be16(nr_sectors, &rq->cmd[7]); + cmd->cmnd[1] = 0x8; /* UNMAP */ + put_unaligned_be32(sector, &cmd->cmnd[2]); + put_unaligned_be16(nr_sectors, &cmd->cmnd[7]); len = sdkp->device->sector_size; break; @@ -756,8 +755,21 @@ static int sd_setup_discard_cmnd(struct scsi_device *sdp, struct request *rq) } rq->completion_data = page; + rq->timeout = SD_TIMEOUT; + + cmd->transfersize = len; + cmd->allowed = rq->retries; + + /* + * Initially __data_len is set to the amount of data that needs to be + * transferred to the target. This amount depends on whether WRITE SAME + * or UNMAP is being used. After the scatterlist has been mapped by + * scsi_init_io() we set __data_len to the size of the area to be + * discarded on disk. This allows us to report completion on the full + * amount of blocks described by the request. + */ blk_add_request_payload(rq, page, len); - ret = scsi_setup_blk_pc_cmnd(sdp, rq); + ret = scsi_init_io(cmd, GFP_ATOMIC); rq->__data_len = nr_bytes; out: @@ -903,7 +915,7 @@ static int sd_init_command(struct scsi_cmnd *SCpnt) * block PC requests to make life easier. */ if (rq->cmd_flags & REQ_DISCARD) { - ret = sd_setup_discard_cmnd(sdp, rq); + ret = sd_setup_discard_cmnd(SCpnt); goto out; } else if (rq->cmd_flags & REQ_WRITE_SAME) { ret = sd_setup_write_same_cmnd(SCpnt); -- 2.45.2