From e537a36d528053f6b9dbe6c88e763e835c0d3517 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Sun, 5 Jun 2005 02:07:14 -0500 Subject: [PATCH] [SCSI] use scatter lists for all block pc requests and simplify hw handlers Here's the proof of concept for this one. It converts scsi_wait_req to do correct REQ_BLOCK_PC submission (and works nicely in my setup). The final goal should be to eliminate struct scsi_request, but that can't be done until the character submission paths of sg and st are also modified. There's some loss of functionality to this: retries are no longer controllable (except by setting REQ_FASTFAIL) and the wait_req API needs to be altered, but it looks very nice. Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 96 ++++++++++++++++++++++++++++++------------------- 1 file changed, 59 insertions(+), 37 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 7a91ca3..253c1a9 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -232,23 +232,6 @@ void scsi_do_req(struct scsi_request *sreq, const void *cmnd, } EXPORT_SYMBOL(scsi_do_req); -static void scsi_wait_done(struct scsi_cmnd *cmd) -{ - struct request *req = cmd->request; - struct request_queue *q = cmd->device->request_queue; - unsigned long flags; - - req->rq_status = RQ_SCSI_DONE; /* Busy, but indicate request done */ - - spin_lock_irqsave(q->queue_lock, flags); - if (blk_rq_tagged(req)) - blk_queue_end_tag(q, req); - spin_unlock_irqrestore(q->queue_lock, flags); - - if (req->waiting) - complete(req->waiting); -} - /* This is the end routine we get to if a command was never attached * to the request. Simply complete the request without changing * rq_status; this will cause a DRIVER_ERROR. */ @@ -263,19 +246,36 @@ void scsi_wait_req(struct scsi_request *sreq, const void *cmnd, void *buffer, unsigned bufflen, int timeout, int retries) { DECLARE_COMPLETION(wait); - - sreq->sr_request->waiting = &wait; - sreq->sr_request->rq_status = RQ_SCSI_BUSY; - sreq->sr_request->end_io = scsi_wait_req_end_io; - scsi_do_req(sreq, cmnd, buffer, bufflen, scsi_wait_done, - timeout, retries); + struct request *req; + + if (bufflen) + req = blk_rq_map_kern(sreq->sr_device->request_queue, + sreq->sr_data_direction == DMA_TO_DEVICE, + buffer, bufflen, __GFP_WAIT); + else + req = blk_get_request(sreq->sr_device->request_queue, READ, + __GFP_WAIT); + req->flags |= REQ_NOMERGE; + req->waiting = &wait; + req->end_io = scsi_wait_req_end_io; + req->cmd_len = COMMAND_SIZE(((u8 *)cmnd)[0]); + req->sense = sreq->sr_sense_buffer; + req->sense_len = 0; + memcpy(req->cmd, cmnd, req->cmd_len); + req->timeout = timeout; + req->flags |= REQ_BLOCK_PC; + req->rq_disk = NULL; + blk_insert_request(sreq->sr_device->request_queue, req, + sreq->sr_data_direction == DMA_TO_DEVICE, NULL); wait_for_completion(&wait); sreq->sr_request->waiting = NULL; - if (sreq->sr_request->rq_status != RQ_SCSI_DONE) + sreq->sr_result = req->errors; + if (req->errors) sreq->sr_result |= (DRIVER_ERROR << 24); - __scsi_release_request(sreq); + blk_put_request(req); } + EXPORT_SYMBOL(scsi_wait_req); /* @@ -878,11 +878,12 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, return; } if (result) { - printk(KERN_INFO "SCSI error : <%d %d %d %d> return code " - "= 0x%x\n", cmd->device->host->host_no, - cmd->device->channel, - cmd->device->id, - cmd->device->lun, result); + if (!(req->flags & REQ_SPECIAL)) + printk(KERN_INFO "SCSI error : <%d %d %d %d> return code " + "= 0x%x\n", cmd->device->host->host_no, + cmd->device->channel, + cmd->device->id, + cmd->device->lun, result); if (driver_byte(result) & DRIVER_SENSE) scsi_print_sense("", cmd); @@ -1020,6 +1021,12 @@ static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, return -EOPNOTSUPP; } +static void scsi_generic_done(struct scsi_cmnd *cmd) +{ + BUG_ON(!blk_pc_request(cmd->request)); + scsi_io_completion(cmd, cmd->result == 0 ? cmd->bufflen : 0, 0); +} + static int scsi_prep_fn(struct request_queue *q, struct request *req) { struct scsi_device *sdev = q->queuedata; @@ -1061,7 +1068,7 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req) * these two cases differently. We differentiate by looking * at request->cmd, as this tells us the real story. */ - if (req->flags & REQ_SPECIAL) { + if (req->flags & REQ_SPECIAL && req->special) { struct scsi_request *sreq = req->special; if (sreq->sr_magic == SCSI_REQ_MAGIC) { @@ -1073,7 +1080,7 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req) cmd = req->special; } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { - if(unlikely(specials_only)) { + if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { if(specials_only == SDEV_QUIESCE || specials_only == SDEV_BLOCK) return BLKPREP_DEFER; @@ -1142,11 +1149,26 @@ static int scsi_prep_fn(struct request_queue *q, struct request *req) /* * Initialize the actual SCSI command for this request. */ - drv = *(struct scsi_driver **)req->rq_disk->private_data; - if (unlikely(!drv->init_command(cmd))) { - scsi_release_buffers(cmd); - scsi_put_command(cmd); - return BLKPREP_KILL; + if (req->rq_disk) { + drv = *(struct scsi_driver **)req->rq_disk->private_data; + if (unlikely(!drv->init_command(cmd))) { + scsi_release_buffers(cmd); + scsi_put_command(cmd); + return BLKPREP_KILL; + } + } else { + memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); + if (rq_data_dir(req) == WRITE) + cmd->sc_data_direction = DMA_TO_DEVICE; + else if (req->data_len) + cmd->sc_data_direction = DMA_FROM_DEVICE; + else + cmd->sc_data_direction = DMA_NONE; + + cmd->transfersize = req->data_len; + cmd->allowed = 3; + cmd->timeout_per_command = req->timeout; + cmd->done = scsi_generic_done; } } -- 2.7.4