scsi: reintroduce scsi_driver.init_command

Instead of letting the ULD play games with the prep_fn move back to
the model of a central prep_fn with a callback to the ULD.  This
already cleans up and shortens the code by itself, and will be required
to properly support blk-mq in the SCSI midlayer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 045822b..9f841df 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1073,15 +1073,7 @@ static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
 
 int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 {
-       struct scsi_cmnd *cmd;
-       int ret = scsi_prep_state_check(sdev, req);
-
-       if (ret != BLKPREP_OK)
-               return ret;
-
-       cmd = scsi_get_cmd_from_req(sdev, req);
-       if (unlikely(!cmd))
-               return BLKPREP_DEFER;
+       struct scsi_cmnd *cmd = req->special;
 
        /*
         * BLOCK_PC requests may transfer data, in which case they must
@@ -1125,15 +1117,11 @@ EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
  */
 int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
 {
-       struct scsi_cmnd *cmd;
-       int ret = scsi_prep_state_check(sdev, req);
-
-       if (ret != BLKPREP_OK)
-               return ret;
+       struct scsi_cmnd *cmd = req->special;
 
        if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh
                         && sdev->scsi_dh_data->scsi_dh->prep_fn)) {
-               ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
+               int ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req);
                if (ret != BLKPREP_OK)
                        return ret;
        }
@@ -1143,16 +1131,13 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
         */
        BUG_ON(!req->nr_phys_segments);
 
-       cmd = scsi_get_cmd_from_req(sdev, req);
-       if (unlikely(!cmd))
-               return BLKPREP_DEFER;
-
        memset(cmd->cmnd, 0, BLK_MAX_CDB);
        return scsi_init_io(cmd, GFP_ATOMIC);
 }
 EXPORT_SYMBOL(scsi_setup_fs_cmnd);
 
-int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
+static int
+scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
 {
        int ret = BLKPREP_OK;
 
@@ -1204,9 +1189,9 @@ int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
        }
        return ret;
 }
-EXPORT_SYMBOL(scsi_prep_state_check);
 
-int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
+static int
+scsi_prep_return(struct request_queue *q, struct request *req, int ret)
 {
        struct scsi_device *sdev = q->queuedata;
 
@@ -1237,18 +1222,44 @@ int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
 
        return ret;
 }
-EXPORT_SYMBOL(scsi_prep_return);
 
-int scsi_prep_fn(struct request_queue *q, struct request *req)
+static int scsi_prep_fn(struct request_queue *q, struct request *req)
 {
        struct scsi_device *sdev = q->queuedata;
-       int ret = BLKPREP_KILL;
+       struct scsi_cmnd *cmd;
+       int ret;
 
-       if (req->cmd_type == REQ_TYPE_BLOCK_PC)
+       ret = scsi_prep_state_check(sdev, req);
+       if (ret != BLKPREP_OK)
+               goto out;
+
+       cmd = scsi_get_cmd_from_req(sdev, req);
+       if (unlikely(!cmd)) {
+               ret = BLKPREP_DEFER;
+               goto out;
+       }
+
+       if (req->cmd_type == REQ_TYPE_FS)
+               ret = scsi_cmd_to_driver(cmd)->init_command(cmd);
+       else if (req->cmd_type == REQ_TYPE_BLOCK_PC)
                ret = scsi_setup_blk_pc_cmnd(sdev, req);
+       else
+               ret = BLKPREP_KILL;
+
+out:
        return scsi_prep_return(q, req, ret);
 }
-EXPORT_SYMBOL(scsi_prep_fn);
+
+static void scsi_unprep_fn(struct request_queue *q, struct request *req)
+{
+       if (req->cmd_type == REQ_TYPE_FS) {
+               struct scsi_cmnd *cmd = req->special;
+               struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
+
+               if (drv->uninit_command)
+                       drv->uninit_command(cmd);
+       }
+}
 
 /*
  * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
@@ -1669,6 +1680,7 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
                return NULL;
 
        blk_queue_prep_rq(q, scsi_prep_fn);
+       blk_queue_unprep_rq(q, scsi_unprep_fn);
        blk_queue_softirq_done(q, scsi_softirq_done);
        blk_queue_rq_timed_out(q, scsi_times_out);
        blk_queue_lld_busy(q, scsi_lld_busy);

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index efcbcd1..aa028d8 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -109,6 +109,8 @@ static int sd_suspend_system(struct device *);
 static int sd_suspend_runtime(struct device *);
 static int sd_resume(struct device *);
 static void sd_rescan(struct device *);
+static int sd_init_command(struct scsi_cmnd *SCpnt);
+static void sd_uninit_command(struct scsi_cmnd *SCpnt);
 static int sd_done(struct scsi_cmnd *);
 static int sd_eh_action(struct scsi_cmnd *, int);
 static void sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer);
@@ -503,6 +505,8 @@ static struct scsi_driver sd_template = {
                .pm             = &sd_pm_ops,
        },
        .rescan                 = sd_rescan,
+       .init_command           = sd_init_command,
+       .uninit_command         = sd_uninit_command,
        .done                   = sd_done,
        .eh_action              = sd_eh_action,
 };
@@ -838,9 +842,9 @@ static int scsi_setup_flush_cmnd(struct scsi_device *sdp, struct request *rq)
        return scsi_setup_blk_pc_cmnd(sdp, rq);
 }
 
-static void sd_unprep_fn(struct request_queue *q, struct request *rq)
+static void sd_uninit_command(struct scsi_cmnd *SCpnt)
 {
-       struct scsi_cmnd *SCpnt = rq->special;
+       struct request *rq = SCpnt->request;
 
        if (rq->cmd_flags & REQ_DISCARD) {
                free_page((unsigned long)rq->buffer);
@@ -853,18 +857,10 @@ static void sd_unprep_fn(struct request_queue *q, struct request *rq)
        }
 }
 
-/**
- *     sd_prep_fn - build a scsi (read or write) command from
- *     information in the request structure.
- *     @SCpnt: pointer to mid-level's per scsi command structure that
- *     contains request and into which the scsi command is written
- *
- *     Returns 1 if successful and 0 if error (or cannot be done now).
- **/
-static int sd_prep_fn(struct request_queue *q, struct request *rq)
+static int sd_init_command(struct scsi_cmnd *SCpnt)
 {
-       struct scsi_cmnd *SCpnt;
-       struct scsi_device *sdp = q->queuedata;
+       struct request *rq = SCpnt->request;
+       struct scsi_device *sdp = SCpnt->device;
        struct gendisk *disk = rq->rq_disk;
        struct scsi_disk *sdkp;
        sector_t block = blk_rq_pos(rq);
@@ -886,12 +882,6 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
        } else if (rq->cmd_flags & REQ_FLUSH) {
                ret = scsi_setup_flush_cmnd(sdp, rq);
                goto out;
-       } else 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_FS) {
-               ret = BLKPREP_KILL;
-               goto out;
        }
        ret = scsi_setup_fs_cmnd(sdp, rq);
        if (ret != BLKPREP_OK)
@@ -903,11 +893,10 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
         * is used for a killable error condition */
        ret = BLKPREP_KILL;
 
-       SCSI_LOG_HLQUEUE(1, scmd_printk(KERN_INFO, SCpnt,
-                                       "sd_prep_fn: block=%llu, "
-                                       "count=%d\n",
-                                       (unsigned long long)block,
-                                       this_count));
+       SCSI_LOG_HLQUEUE(1,
+               scmd_printk(KERN_INFO, SCpnt,
+                       "%s: block=%llu, count=%d\n",
+                       __func__, (unsigned long long)block, this_count));
 
        if (!sdp || !scsi_device_online(sdp) ||
            block + blk_rq_sectors(rq) > get_capacity(disk)) {
@@ -1127,7 +1116,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
         */
        ret = BLKPREP_OK;
  out:
-       return scsi_prep_return(q, rq, ret);
+       return ret;
 }
 
 /**
@@ -2878,9 +2867,6 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
 
        sd_revalidate_disk(gd);
 
-       blk_queue_prep_rq(sdp->request_queue, sd_prep_fn);
-       blk_queue_unprep_rq(sdp->request_queue, sd_unprep_fn);
-
        gd->driverfs_dev = &sdp->sdev_gendev;
        gd->flags = GENHD_FL_EXT_DEVT;
        if (sdp->removable) {
@@ -3028,8 +3014,6 @@ static int sd_remove(struct device *dev)
 
        async_synchronize_full_domain(&scsi_sd_pm_domain);
        async_synchronize_full_domain(&scsi_sd_probe_domain);
-       blk_queue_prep_rq(sdkp->device->request_queue, scsi_prep_fn);
-       blk_queue_unprep_rq(sdkp->device->request_queue, NULL);
        device_del(&sdkp->dev);
        del_gendisk(sdkp->disk);
        sd_shutdown(dev);

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 40d8592..93cbd36 100644 (file)
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -79,6 +79,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_WORM);
 static DEFINE_MUTEX(sr_mutex);
 static int sr_probe(struct device *);
 static int sr_remove(struct device *);
+static int sr_init_command(struct scsi_cmnd *SCpnt);
 static int sr_done(struct scsi_cmnd *);
 static int sr_runtime_suspend(struct device *dev);
 
@@ -94,6 +95,7 @@ static struct scsi_driver sr_template = {
                .remove         = sr_remove,
                .pm             = &sr_pm_ops,
        },
+       .init_command           = sr_init_command,
        .done                   = sr_done,
 };
 
@@ -378,21 +380,14 @@ static int sr_done(struct scsi_cmnd *SCpnt)
        return good_bytes;
 }
 
-static int sr_prep_fn(struct request_queue *q, struct request *rq)
+static int sr_init_command(struct scsi_cmnd *SCpnt)
 {
        int block = 0, this_count, s_size;
        struct scsi_cd *cd;
-       struct scsi_cmnd *SCpnt;
-       struct scsi_device *sdp = q->queuedata;
+       struct request *rq = SCpnt->request;
+       struct scsi_device *sdp = SCpnt->device;
        int ret;
 
-       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_FS) {
-               ret = BLKPREP_KILL;
-               goto out;
-       }
        ret = scsi_setup_fs_cmnd(sdp, rq);
        if (ret != BLKPREP_OK)
                goto out;
@@ -517,7 +512,7 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
         */
        ret = BLKPREP_OK;
  out:
-       return scsi_prep_return(q, rq, ret);
+       return ret;
 }
 
 static int sr_block_open(struct block_device *bdev, fmode_t mode)
@@ -718,7 +713,6 @@ static int sr_probe(struct device *dev)
 
        /* FIXME: need to handle a get_capabilities failure properly ?? */
        get_capabilities(cd);
-       blk_queue_prep_rq(sdev->request_queue, sr_prep_fn);
        sr_vendor_init(cd);
 
        disk->driverfs_dev = &sdev->sdev_gendev;
@@ -993,7 +987,6 @@ static int sr_remove(struct device *dev)
 
        scsi_autopm_get_device(cd->device);
 
-       blk_queue_prep_rq(cd->device->request_queue, scsi_prep_fn);
        del_gendisk(cd->disk);
 
        mutex_lock(&sr_ref_mutex);

diff --git a/include/scsi/scsi_driver.h b/include/scsi/scsi_driver.h
index 20fdfc2..36c4114 100644 (file)
--- a/include/scsi/scsi_driver.h
+++ b/include/scsi/scsi_driver.h
@@ -4,17 +4,17 @@
 #include <linux/device.h>
 
 struct module;
+struct request;
 struct scsi_cmnd;
 struct scsi_device;
-struct request;
-struct request_queue;
-
 
 struct scsi_driver {
        struct module           *owner;
        struct device_driver    gendrv;
 
        void (*rescan)(struct device *);
+       int (*init_command)(struct scsi_cmnd *);
+       void (*uninit_command)(struct scsi_cmnd *);
        int (*done)(struct scsi_cmnd *);
        int (*eh_action)(struct scsi_cmnd *, int);
 };
@@ -31,8 +31,5 @@ extern int scsi_register_interface(struct class_interface *);
 
 int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req);
 int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req);
-int scsi_prep_state_check(struct scsi_device *sdev, struct request *req);
-int scsi_prep_return(struct request_queue *q, struct request *req, int ret);
-int scsi_prep_fn(struct request_queue *, struct request *);
 
 #endif /* _SCSI_SCSI_DRIVER_H */