Elias Oltmanns <eo@xxxxxxxxxxxxxx> wrote: > Hi all, > > this patch adds support for REQ_TYPE_LINUX_BLOCK requests to the scsi > midlayer. Low level drivers have the option to register their own > handlers for these special requests if necessary. > [...] > +static void scsi_finish_lb_req(struct request *req) > +{ > + struct request_queue *q = req->q; > + struct scsi_device *sdev = q->queuedata; > + unsigned long flags; > + > + spin_lock_irqsave(q->queue_lock, flags); > + end_that_request_last(req, 1); That's obsolete, of course. Sorry for missing that. See the correct patch for 2.6.25-rc7 below. Regards, Elias
--- drivers/scsi/scsi_lib.c | 66 +++++++++++++++++++++++++++++++++++++++++++++- drivers/scsi/sd.c | 9 ++++++ drivers/scsi/sr.c | 9 ++++++ include/linux/blkdev.h | 1 + include/scsi/scsi_host.h | 22 +++++++++++++++ 5 files changed, 105 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index f40898d..5e72640 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1262,6 +1262,15 @@ int scsi_prep_fn(struct request_queue *q, struct request *req) if (req->cmd_type == REQ_TYPE_BLOCK_PC) ret = scsi_setup_blk_pc_cmnd(sdev, req); + else if (req->cmd_type == REQ_TYPE_LINUX_BLOCK) { + get_device(&sdev->sdev_gendev); + /* + * Since these requests don't need preparation, we'll + * basically just accept them unconditionally at this + * point. + */ + ret = BLKPREP_OK; + } return scsi_prep_return(q, req, ret); } @@ -1371,12 +1380,31 @@ static void scsi_kill_request(struct request *req, struct request_queue *q) __scsi_done(cmd); } +static void scsi_finish_lb_req(struct request *req) +{ + struct scsi_device *sdev = req->q->queuedata; + + /* + * TODO: Perhaps the data_len or extra_len of + * REQ_TYPE_LINUX_BLOCK requests are allowed to be different + * from 0? + */ + blk_end_request(req, 0, 0); + put_device(&sdev->sdev_gendev); +} + static void scsi_softirq_done(struct request *rq) { struct scsi_cmnd *cmd = rq->completion_data; - unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; + unsigned long wait_for; int disposition; + if (blk_lb_request(rq)) { + scsi_finish_lb_req(rq); + return; + } + + wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; INIT_LIST_HEAD(&cmd->eh_entry); disposition = scsi_decide_disposition(cmd); @@ -1406,6 +1434,24 @@ static void scsi_softirq_done(struct request *rq) } } +static void scsi_exec_lb_req(struct request *req) +{ + struct scsi_device *sdev = req->q->queuedata; + struct scsi_host_template *shostt = sdev->host->hostt; + int rc; + + if (shostt->lb_request_fn) + rc = shostt->lb_request_fn(req); + else + rc = FAILED; + + if (rc == FAILED) + req->errors = -EIO; + else if (rc == QUEUED) + return; + blk_complete_request(req); +} + /* * Function: scsi_request_fn() * @@ -1448,7 +1494,23 @@ static void scsi_request_fn(struct request_queue *q) * accept it. */ req = elv_next_request(q); - if (!req || !scsi_dev_queue_ready(q, sdev)) + if (!req) + break; + + /* + * We do not account for linux blk req in the device + * or host busy accounting because it is not necessarily + * a scsi command that is sent to some object. The lower + * level can translate it into a request/scsi_cmnd, if + * necessary, and then queue that up using REQ_TYPE_BLOCK_PC. + */ + if (blk_lb_request(req)) { + blkdev_dequeue_request(req); + scsi_exec_lb_req(req); + continue; + } + + if (!scsi_dev_queue_ready(q, sdev)) break; if (unlikely(!scsi_device_online(sdev))) { diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 5fe7aae..95eba9f 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -357,6 +357,15 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq) if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { ret = scsi_setup_blk_pc_cmnd(sdp, rq); goto out; + } else if (rq->cmd_type == REQ_TYPE_LINUX_BLOCK) { + get_device(&sdp->sdev_gendev); + /* + * Since these requests don't need preparation, we'll + * basically just accept them unconditionally at this + * point. + */ + ret = BLKPREP_OK; + goto out; } else if (rq->cmd_type != REQ_TYPE_FS) { ret = BLKPREP_KILL; goto out; diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c index 7ee86d4..24bdfae 100644 --- a/drivers/scsi/sr.c +++ b/drivers/scsi/sr.c @@ -337,6 +337,15 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq) if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { ret = scsi_setup_blk_pc_cmnd(sdp, rq); goto out; + } else if (rq->cmd_type == REQ_TYPE_LINUX_BLOCK) { + get_device(&sdp->sdev_gendev); + /* + * Since these requests don't need preparation, we'll + * basically just accept them unconditionally at this + * point. + */ + ret = BLKPREP_OK; + goto out; } else if (rq->cmd_type != REQ_TYPE_FS) { ret = BLKPREP_KILL; goto out; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 6f79d40..f4ed034 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -453,6 +453,7 @@ enum { #define blk_fs_request(rq) ((rq)->cmd_type == REQ_TYPE_FS) #define blk_pc_request(rq) ((rq)->cmd_type == REQ_TYPE_BLOCK_PC) +#define blk_lb_request(rq) ((rq)->cmd_type == REQ_TYPE_LINUX_BLOCK) #define blk_special_request(rq) ((rq)->cmd_type == REQ_TYPE_SPECIAL) #define blk_sense_request(rq) ((rq)->cmd_type == REQ_TYPE_SENSE) diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 530ff4c..1765855 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -9,6 +9,7 @@ #include <scsi/scsi.h> struct request_queue; +struct request; struct block_device; struct completion; struct module; @@ -153,6 +154,27 @@ struct scsi_host_template { void (*done)(struct scsi_cmnd *)); /* + * The lb_request_fn function is used to pass + * REQ_TYPE_LINUX_BLOCK requests to the LLDD. The return value + * FAILED indicates that the command opcode has not been known + * by lb_request_fn. In contrast, the return value SUCCESS + * means that the opcode has been recognised and the request + * has been processed accordingly. Note, however, that SUCCESS + * does not necessarily mean that all actions have been + * performed successfully; errors are recorded in req->errors. + * lb_request_fn can also return QUEUED in order to prevent + * midlayer from enqueueng the request for completion. + * Obviously, the LLDD must take care that the request will be + * completed by means of blk_complete_request eventually. + * + * Status: OPTIONAL + */ + /* TODO: We might need to accept a return value NEEDS_RETRY some + * time. + */ + int (* lb_request_fn)(struct request *req); + + /* * This is an error handling strategy routine. You don't need to * define one of these if you don't want to - there is a default * routine that is present that should work in most cases. For those