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[PATCH] block: support larger block pc requests

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This patch modifies blk_rq_map/unmap_user() and the cdrom and scsi_ioctl.c
users so that it supports requests larger than bio by chaining them together.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Mike Christie 2006-12-01 10:40:55 +01:00 committed by Jens Axboe
parent ad2d722570
commit 0e75f9063f
5 changed files with 163 additions and 93 deletions
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166
block/ll_rw_blk.c
View File

@ -2322,6 +2322,84 @@ void blk_insert_request(request_queue_t *q, struct request *rq,
EXPORT_SYMBOL(blk_insert_request);
static int __blk_rq_unmap_user(struct bio *bio)
{
int ret = 0;
if (bio) {
if (bio_flagged(bio, BIO_USER_MAPPED))
bio_unmap_user(bio);
else
ret = bio_uncopy_user(bio);
}
return ret;
}
static int __blk_rq_map_user(request_queue_t *q, struct request *rq,
void __user *ubuf, unsigned int len)
{
unsigned long uaddr;
struct bio *bio, *orig_bio;
int reading, ret;
reading = rq_data_dir(rq) == READ;
/*
* if alignment requirement is satisfied, map in user pages for
* direct dma. else, set up kernel bounce buffers
*/
uaddr = (unsigned long) ubuf;
if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
bio = bio_map_user(q, NULL, uaddr, len, reading);
else
bio = bio_copy_user(q, uaddr, len, reading);
if (IS_ERR(bio)) {
return PTR_ERR(bio);
}
orig_bio = bio;
blk_queue_bounce(q, &bio);
/*
* We link the bounce buffer in and could have to traverse it
* later so we have to get a ref to prevent it from being freed
*/
bio_get(bio);
/*
* for most (all? don't know of any) queues we could
* skip grabbing the queue lock here. only drivers with
* funky private ->back_merge_fn() function could be
* problematic.
*/
spin_lock_irq(q->queue_lock);
if (!rq->bio)
blk_rq_bio_prep(q, rq, bio);
else if (!q->back_merge_fn(q, rq, bio)) {
ret = -EINVAL;
spin_unlock_irq(q->queue_lock);
goto unmap_bio;
} else {
rq->biotail->bi_next = bio;
rq->biotail = bio;
rq->nr_sectors += bio_sectors(bio);
rq->hard_nr_sectors = rq->nr_sectors;
rq->data_len += bio->bi_size;
}
spin_unlock_irq(q->queue_lock);
return bio->bi_size;
unmap_bio:
/* if it was boucned we must call the end io function */
bio_endio(bio, bio->bi_size, 0);
__blk_rq_unmap_user(orig_bio);
bio_put(bio);
return ret;
}
/**
* blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
* @q: request queue where request should be inserted
@ -2343,42 +2421,44 @@ EXPORT_SYMBOL(blk_insert_request);
* unmapping.
*/
int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
unsigned int len)
unsigned long len)
{
unsigned long uaddr;
struct bio *bio;
int reading;
unsigned long bytes_read = 0;
int ret;
if (len > (q->max_hw_sectors << 9))
return -EINVAL;
if (!len || !ubuf)
return -EINVAL;
reading = rq_data_dir(rq) == READ;
while (bytes_read != len) {
unsigned long map_len, end, start;
/*
* if alignment requirement is satisfied, map in user pages for
* direct dma. else, set up kernel bounce buffers
*/
uaddr = (unsigned long) ubuf;
if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
bio = bio_map_user(q, NULL, uaddr, len, reading);
else
bio = bio_copy_user(q, uaddr, len, reading);
map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
>> PAGE_SHIFT;
start = (unsigned long)ubuf >> PAGE_SHIFT;
if (!IS_ERR(bio)) {
rq->bio = rq->biotail = bio;
blk_rq_bio_prep(q, rq, bio);
/*
* A bad offset could cause us to require BIO_MAX_PAGES + 1
* pages. If this happens we just lower the requested
* mapping len by a page so that we can fit
*/
if (end - start > BIO_MAX_PAGES)
map_len -= PAGE_SIZE;
rq->buffer = rq->data = NULL;
rq->data_len = len;
return 0;
ret = __blk_rq_map_user(q, rq, ubuf, map_len);
if (ret < 0)
goto unmap_rq;
bytes_read += ret;
ubuf += ret;
}
/*
* bio is the err-ptr
*/
return PTR_ERR(bio);
rq->buffer = rq->data = NULL;
return 0;
unmap_rq:
blk_rq_unmap_user(rq);
return ret;
}
EXPORT_SYMBOL(blk_rq_map_user);
@ -2404,7 +2484,7 @@ EXPORT_SYMBOL(blk_rq_map_user);
* unmapping.
*/
int blk_rq_map_user_iov(request_queue_t *q, struct request *rq,
struct sg_iovec *iov, int iov_count)
struct sg_iovec *iov, int iov_count, unsigned int len)
{
struct bio *bio;
@ -2418,10 +2498,15 @@ int blk_rq_map_user_iov(request_queue_t *q, struct request *rq,
if (IS_ERR(bio))
return PTR_ERR(bio);
rq->bio = rq->biotail = bio;
if (bio->bi_size != len) {
bio_endio(bio, bio->bi_size, 0);
bio_unmap_user(bio);
return -EINVAL;
}
bio_get(bio);
blk_rq_bio_prep(q, rq, bio);
rq->buffer = rq->data = NULL;
rq->data_len = bio->bi_size;
return 0;
}
@ -2429,23 +2514,26 @@ EXPORT_SYMBOL(blk_rq_map_user_iov);
/**
* blk_rq_unmap_user - unmap a request with user data
* @bio: bio to be unmapped
* @ulen: length of user buffer
* @rq: rq to be unmapped
*
* Description:
* Unmap a bio previously mapped by blk_rq_map_user().
* Unmap a rq previously mapped by blk_rq_map_user().
* rq->bio must be set to the original head of the request.
*/
int blk_rq_unmap_user(struct bio *bio, unsigned int ulen)
int blk_rq_unmap_user(struct request *rq)
{
int ret = 0;
struct bio *bio, *mapped_bio;
if (bio) {
if (bio_flagged(bio, BIO_USER_MAPPED))
bio_unmap_user(bio);
while ((bio = rq->bio)) {
if (bio_flagged(bio, BIO_BOUNCED))
mapped_bio = bio->bi_private;
else
ret = bio_uncopy_user(bio);
}
mapped_bio = bio;
__blk_rq_unmap_user(mapped_bio);
rq->bio = bio->bi_next;
bio_put(bio);
}
return 0;
}
@ -2476,11 +2564,8 @@ int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf,
if (rq_data_dir(rq) == WRITE)
bio->bi_rw |= (1 << BIO_RW);
rq->bio = rq->biotail = bio;
blk_rq_bio_prep(q, rq, bio);
rq->buffer = rq->data = NULL;
rq->data_len = len;
return 0;
}
@ -3495,6 +3580,7 @@ void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio)
rq->hard_cur_sectors = rq->current_nr_sectors;
rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio);
rq->buffer = bio_data(bio);
rq->data_len = bio->bi_size;
rq->bio = rq->biotail = bio;
}

59
block/scsi_ioctl.c
View File

@ -226,7 +226,6 @@ static int sg_io(struct file *file, request_queue_t *q,
unsigned long start_time;
int writing = 0, ret = 0;
struct request *rq;
struct bio *bio;
char sense[SCSI_SENSE_BUFFERSIZE];
unsigned char cmd[BLK_MAX_CDB];
@ -258,6 +257,32 @@ static int sg_io(struct file *file, request_queue_t *q,
if (!rq)
return -ENOMEM;
/*
* fill in request structure
*/
rq->cmd_len = hdr->cmd_len;
memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
memcpy(rq->cmd, cmd, hdr->cmd_len);
memset(sense, 0, sizeof(sense));
rq->sense = sense;
rq->sense_len = 0;
rq->cmd_type = REQ_TYPE_BLOCK_PC;
/*
* bounce this after holding a reference to the original bio, it's
* needed for proper unmapping
*/
if (rq->bio)
blk_queue_bounce(q, &rq->bio);
rq->timeout = (hdr->timeout * HZ) / 1000;
if (!rq->timeout)
rq->timeout = q->sg_timeout;
if (!rq->timeout)
rq->timeout = BLK_DEFAULT_TIMEOUT;
if (hdr->iovec_count) {
const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
struct sg_iovec *iov;
@ -274,7 +299,8 @@ static int sg_io(struct file *file, request_queue_t *q,
goto out;
}
ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count);
ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count,
hdr->dxfer_len);
kfree(iov);
} else if (hdr->dxfer_len)
ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);
@ -282,33 +308,6 @@ static int sg_io(struct file *file, request_queue_t *q,
if (ret)
goto out;
/*
* fill in request structure
*/
rq->cmd_len = hdr->cmd_len;
memset(rq->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
memcpy(rq->cmd, cmd, hdr->cmd_len);
memset(sense, 0, sizeof(sense));
rq->sense = sense;
rq->sense_len = 0;
rq->cmd_type = REQ_TYPE_BLOCK_PC;
bio = rq->bio;
/*
* bounce this after holding a reference to the original bio, it's
* needed for proper unmapping
*/
if (rq->bio)
blk_queue_bounce(q, &rq->bio);
rq->timeout = (hdr->timeout * HZ) / 1000;
if (!rq->timeout)
rq->timeout = q->sg_timeout;
if (!rq->timeout)
rq->timeout = BLK_DEFAULT_TIMEOUT;
rq->retries = 0;
start_time = jiffies;
@ -339,7 +338,7 @@ static int sg_io(struct file *file, request_queue_t *q,
hdr->sb_len_wr = len;
}
if (blk_rq_unmap_user(bio, hdr->dxfer_len))
if (blk_rq_unmap_user(rq))
ret = -EFAULT;
/* may not have succeeded, but output values written to control

6
drivers/cdrom/cdrom.c
View File

@ -2133,16 +2133,14 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
rq->timeout = 60 * HZ;
bio = rq->bio;
if (rq->bio)
blk_queue_bounce(q, &rq->bio);
if (blk_execute_rq(q, cdi->disk, rq, 0)) {
struct request_sense *s = rq->sense;
ret = -EIO;
cdi->last_sense = s->sense_key;
}
if (blk_rq_unmap_user(bio, len))
rq->bio = bio;
if (blk_rq_unmap_user(rq))
ret = -EFAULT;
if (ret)

18
fs/bio.c
View File

@ -560,10 +560,8 @@ struct bio *bio_copy_user(request_queue_t *q, unsigned long uaddr,
break;
}
if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
ret = -EINVAL;
if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes)
break;
}
len -= bytes;
}
@ -750,7 +748,6 @@ struct bio *bio_map_user_iov(request_queue_t *q, struct block_device *bdev,
int write_to_vm)
{
struct bio *bio;
int len = 0, i;
bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm);
@ -765,18 +762,7 @@ struct bio *bio_map_user_iov(request_queue_t *q, struct block_device *bdev,
*/
bio_get(bio);
for (i = 0; i < iov_count; i++)
len += iov[i].iov_len;
if (bio->bi_size == len)
return bio;
/*
* don't support partial mappings
*/
bio_endio(bio, bio->bi_size, 0);
bio_unmap_user(bio);
return ERR_PTR(-EINVAL);
return bio;
}
static void __bio_unmap_user(struct bio *bio)

7
include/linux/blkdev.h
View File

@ -678,10 +678,11 @@ extern void __blk_stop_queue(request_queue_t *q);
extern void blk_run_queue(request_queue_t *);
extern void blk_start_queueing(request_queue_t *);
extern void blk_queue_activity_fn(request_queue_t *, activity_fn *, void *);
extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
extern int blk_rq_unmap_user(struct bio *, unsigned int);
extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned long);
extern int blk_rq_unmap_user(struct request *);
extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
extern int blk_rq_map_user_iov(request_queue_t *, struct request *,
struct sg_iovec *, int, unsigned int);
extern int blk_execute_rq(request_queue_t *, struct gendisk *,
struct request *, int);
extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,