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scsi: reintroduce scsi_driver.init_command
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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>
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Christoph Hellwig committed May 19, 2014
1 parent bc85dc5 commit a1b73fc
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Showing 4 changed files with 62 additions and 76 deletions.
66 changes: 39 additions & 27 deletions drivers/scsi/scsi_lib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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;
}
Expand All @@ -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;

Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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);
Expand Down
44 changes: 14 additions & 30 deletions drivers/scsi/sd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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,
};
Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand All @@ -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)
Expand All @@ -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)) {
Expand Down Expand Up @@ -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;
}

/**
Expand Down Expand Up @@ -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) {
Expand Down Expand Up @@ -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);
Expand Down
19 changes: 6 additions & 13 deletions drivers/scsi/sr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);

Expand All @@ -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,
};

Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down
9 changes: 3 additions & 6 deletions include/scsi/scsi_driver.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
};
Expand All @@ -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 */

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