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[SCSI] Convert SCSI mid-layer to scsi_execute_async 

Add scsi helpers to create really-large-requests and convert
scsi-ml to scsi_execute_async().

Per Jens's previous comments, I placed this function in scsi_lib.c.
I made it follow all the queue's limits - I think I did at least :), so
I removed the warning on the function header.

I think the scsi_execute_* functions should eventually take a request_queue
and be placed some place where the dm-multipath hw_handler can use them
if that failover code is going to stay in the kernel. That conversion
patch will be sent in another mail though.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This commit is contained in:
Mike Christie 2005-11-11 05:30:27 -06:00 committed by James Bottomley
parent 6e39b69e7e
commit 6e68af666f
6 changed files with 233 additions and 73 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/scsi/scsi_error.c
View File

@ -1314,23 +1314,6 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
}
}
/**
* scsi_eh_lock_done - done function for eh door lock request
* @scmd: SCSI command block for the door lock request
*
* Notes:
* We completed the asynchronous door lock request, and it has either
* locked the door or failed. We must free the command structures
* associated with this request.
**/
static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
{
struct scsi_request *sreq = scmd->sc_request;
scsi_release_request(sreq);
}
/**
* scsi_eh_lock_door - Prevent medium removal for the specified device
* @sdev: SCSI device to prevent medium removal
@ -1353,29 +1336,17 @@ static void scsi_eh_lock_done(struct scsi_cmnd *scmd)
**/
static void scsi_eh_lock_door(struct scsi_device *sdev)
{
struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL);
unsigned char cmnd[MAX_COMMAND_SIZE];
if (unlikely(!sreq)) {
printk(KERN_ERR "%s: request allocate failed,"
"prevent media removal cmd not sent\n", __FUNCTION__);
return;
}
cmnd[0] = ALLOW_MEDIUM_REMOVAL;
cmnd[1] = 0;
cmnd[2] = 0;
cmnd[3] = 0;
cmnd[4] = SCSI_REMOVAL_PREVENT;
cmnd[5] = 0;
sreq->sr_cmnd[0] = ALLOW_MEDIUM_REMOVAL;
sreq->sr_cmnd[1] = 0;
sreq->sr_cmnd[2] = 0;
sreq->sr_cmnd[3] = 0;
sreq->sr_cmnd[4] = SCSI_REMOVAL_PREVENT;
sreq->sr_cmnd[5] = 0;
sreq->sr_data_direction = DMA_NONE;
sreq->sr_bufflen = 0;
sreq->sr_buffer = NULL;
sreq->sr_allowed = 5;
sreq->sr_done = scsi_eh_lock_done;
sreq->sr_timeout_per_command = 10 * HZ;
sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]);
scsi_insert_special_req(sreq, 1);
scsi_execute_async(sdev, cmnd, DMA_NONE, NULL, 0, 0, 10 * HZ,
5, NULL, NULL, GFP_KERNEL);
}

230
drivers/scsi/scsi_lib.c
View File

@ -63,39 +63,6 @@ static struct scsi_host_sg_pool scsi_sg_pools[] = {
};
#undef SP
/*
* Function: scsi_insert_special_req()
*
* Purpose: Insert pre-formed request into request queue.
*
* Arguments: sreq - request that is ready to be queued.
* at_head - boolean. True if we should insert at head
* of queue, false if we should insert at tail.
*
* Lock status: Assumed that lock is not held upon entry.
*
* Returns: Nothing
*
* Notes: This function is called from character device and from
* ioctl types of functions where the caller knows exactly
* what SCSI command needs to be issued. The idea is that
* we merely inject the command into the queue (at the head
* for now), and then call the queue request function to actually
* process it.
*/
int scsi_insert_special_req(struct scsi_request *sreq, int at_head)
{
/*
* Because users of this function are apt to reuse requests with no
* modification, we have to sanitise the request flags here
*/
sreq->sr_request->flags &= ~REQ_DONTPREP;
blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request,
at_head, sreq);
return 0;
}
static void scsi_run_queue(struct request_queue *q);
/*
@ -249,8 +216,13 @@ void scsi_do_req(struct scsi_request *sreq, const void *cmnd,
/*
* head injection *required* here otherwise quiesce won't work
*
* Because users of this function are apt to reuse requests with no
* modification, we have to sanitise the request flags here
*/
scsi_insert_special_req(sreq, 1);
sreq->sr_request->flags &= ~REQ_DONTPREP;
blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request,
1, sreq);
}
EXPORT_SYMBOL(scsi_do_req);
@ -327,6 +299,196 @@ int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
}
EXPORT_SYMBOL(scsi_execute_req);
struct scsi_io_context {
void *data;
void (*done)(void *data, char *sense, int result, int resid);
char sense[SCSI_SENSE_BUFFERSIZE];
};
static void scsi_end_async(struct request *req)
{
struct scsi_io_context *sioc = req->end_io_data;
if (sioc->done)
sioc->done(sioc->data, sioc->sense, req->errors, req->data_len);
kfree(sioc);
__blk_put_request(req->q, req);
}
static int scsi_merge_bio(struct request *rq, struct bio *bio)
{
struct request_queue *q = rq->q;
bio->bi_flags &= ~(1 << BIO_SEG_VALID);
if (rq_data_dir(rq) == WRITE)
bio->bi_rw |= (1 << BIO_RW);
blk_queue_bounce(q, &bio);
if (!rq->bio)
blk_rq_bio_prep(q, rq, bio);
else if (!q->back_merge_fn(q, rq, bio))
return -EINVAL;
else {
rq->biotail->bi_next = bio;
rq->biotail = bio;
rq->hard_nr_sectors += bio_sectors(bio);
rq->nr_sectors = rq->hard_nr_sectors;
}
return 0;
}
static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error)
{
if (bio->bi_size)
return 1;
bio_put(bio);
return 0;
}
/**
* scsi_req_map_sg - map a scatterlist into a request
* @rq: request to fill
* @sg: scatterlist
* @nsegs: number of elements
* @bufflen: len of buffer
* @gfp: memory allocation flags
*
* scsi_req_map_sg maps a scatterlist into a request so that the
* request can be sent to the block layer. We do not trust the scatterlist
* sent to use, as some ULDs use that struct to only organize the pages.
*/
static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
int nsegs, unsigned bufflen, gfp_t gfp)
{
struct request_queue *q = rq->q;
int nr_pages = (bufflen + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned int data_len = 0, len, bytes, off;
struct page *page;
struct bio *bio = NULL;
int i, err, nr_vecs = 0;
for (i = 0; i < nsegs; i++) {
page = sgl[i].page;
off = sgl[i].offset;
len = sgl[i].length;
data_len += len;
while (len > 0) {
bytes = min_t(unsigned int, len, PAGE_SIZE - off);
if (!bio) {
nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages);
nr_pages -= nr_vecs;
bio = bio_alloc(gfp, nr_vecs);
if (!bio) {
err = -ENOMEM;
goto free_bios;
}
bio->bi_end_io = scsi_bi_endio;
}
if (bio_add_pc_page(q, bio, page, bytes, off) !=
bytes) {
bio_put(bio);
err = -EINVAL;
goto free_bios;
}
if (bio->bi_vcnt >= nr_vecs) {
err = scsi_merge_bio(rq, bio);
if (err) {
bio_endio(bio, bio->bi_size, 0);
goto free_bios;
}
bio = NULL;
}
page++;
len -= bytes;
off = 0;
}
}
rq->buffer = rq->data = NULL;
rq->data_len = data_len;
return 0;
free_bios:
while ((bio = rq->bio) != NULL) {
rq->bio = bio->bi_next;
/*
* call endio instead of bio_put incase it was bounced
*/
bio_endio(bio, bio->bi_size, 0);
}
return err;
}
/**
* scsi_execute_async - insert request
* @sdev: scsi device
* @cmd: scsi command
* @data_direction: data direction
* @buffer: data buffer (this can be a kernel buffer or scatterlist)
* @bufflen: len of buffer
* @use_sg: if buffer is a scatterlist this is the number of elements
* @timeout: request timeout in seconds
* @retries: number of times to retry request
* @flags: or into request flags
**/
int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
int data_direction, void *buffer, unsigned bufflen,
int use_sg, int timeout, int retries, void *privdata,
void (*done)(void *, char *, int, int), gfp_t gfp)
{
struct request *req;
struct scsi_io_context *sioc;
int err = 0;
int write = (data_direction == DMA_TO_DEVICE);
sioc = kzalloc(sizeof(*sioc), gfp);
if (!sioc)
return DRIVER_ERROR << 24;
req = blk_get_request(sdev->request_queue, write, gfp);
if (!req)
goto free_sense;
if (use_sg)
err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
else if (bufflen)
err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp);
if (err)
goto free_req;
req->cmd_len = COMMAND_SIZE(cmd[0]);
memcpy(req->cmd, cmd, req->cmd_len);
req->sense = sioc->sense;
req->sense_len = 0;
req->timeout = timeout;
req->flags |= REQ_BLOCK_PC | REQ_QUIET;
req->end_io_data = sioc;
sioc->data = privdata;
sioc->done = done;
blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async);
return 0;
free_req:
blk_put_request(req);
free_sense:
kfree(sioc);
return DRIVER_ERROR << 24;
}
EXPORT_SYMBOL_GPL(scsi_execute_async);
/*
* Function: scsi_init_cmd_errh()
*

1
drivers/scsi/scsi_priv.h
View File

@ -40,7 +40,6 @@ extern void scsi_exit_hosts(void);
extern int scsi_dispatch_cmd(struct scsi_cmnd *cmd);
extern int scsi_setup_command_freelist(struct Scsi_Host *shost);
extern void scsi_destroy_command_freelist(struct Scsi_Host *shost);
extern int scsi_insert_special_req(struct scsi_request *sreq, int);
extern void scsi_init_cmd_from_req(struct scsi_cmnd *cmd,
struct scsi_request *sreq);
extern void __scsi_release_request(struct scsi_request *sreq);

20
fs/bio.c
View File

@ -385,6 +385,25 @@ static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
return len;
}
/**
* bio_add_pc_page - attempt to add page to bio
* @bio: destination bio
* @page: page to add
* @len: vec entry length
* @offset: vec entry offset
*
* Attempt to add a page to the bio_vec maplist. This can fail for a
* number of reasons, such as the bio being full or target block
* device limitations. The target block device must allow bio's
* smaller than PAGE_SIZE, so it is always possible to add a single
* page to an empty bio. This should only be used by REQ_PC bios.
*/
int bio_add_pc_page(request_queue_t *q, struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
return __bio_add_page(q, bio, page, len, offset);
}
/**
* bio_add_page - attempt to add page to bio
* @bio: destination bio
@ -1228,6 +1247,7 @@ EXPORT_SYMBOL(bio_clone);
EXPORT_SYMBOL(bio_phys_segments);
EXPORT_SYMBOL(bio_hw_segments);
EXPORT_SYMBOL(bio_add_page);
EXPORT_SYMBOL(bio_add_pc_page);
EXPORT_SYMBOL(bio_get_nr_vecs);
EXPORT_SYMBOL(bio_map_user);
EXPORT_SYMBOL(bio_unmap_user);

2
include/linux/bio.h
View File

@ -292,6 +292,8 @@ extern struct bio *bio_clone(struct bio *, gfp_t);
extern void bio_init(struct bio *);
extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
unsigned int, unsigned int);
extern int bio_get_nr_vecs(struct block_device *);
extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
unsigned long, unsigned int, int);

6
include/scsi/scsi_device.h
View File

@ -274,6 +274,12 @@ extern int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
int data_direction, void *buffer, unsigned bufflen,
struct scsi_sense_hdr *, int timeout, int retries);
extern int scsi_execute_async(struct scsi_device *sdev,
const unsigned char *cmd, int data_direction,
void *buffer, unsigned bufflen, int use_sg,
int timeout, int retries, void *privdata,
void (*done)(void *, char *, int, int),
gfp_t gfp);
static inline unsigned int sdev_channel(struct scsi_device *sdev)
{