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Commit 0e75f906 authored by Mike Christie's avatar Mike Christie Committed by Jens Axboe
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[PATCH] block: support larger block pc requests 



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: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent ad2d7225

block/ll_rw_blk.c

+126 −40
Original line number Diff line number Diff line
@@ -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;



		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 alignment requirement is satisfied, map in user pages for

	 * direct dma. else, set up kernel bounce buffers

		 * 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

		 */

	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 (end - start > BIO_MAX_PAGES)

			map_len -= PAGE_SIZE;



	if (!IS_ERR(bio)) {

		rq->bio = rq->biotail = bio;

		blk_rq_bio_prep(q, rq, bio);

		ret = __blk_rq_map_user(q, rq, ubuf, map_len);

		if (ret < 0)

			goto unmap_rq;

		bytes_read += ret;

		ubuf += ret;

	}



	rq->buffer = rq->data = NULL;

		rq->data_len = len;

	return 0;

	}



	/*

	 * bio is the err-ptr

	 */

	return PTR_ERR(bio);

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;

}

block/scsi_ioctl.c

+26 −27
Original line number Diff line number Diff line
@@ -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];
@@ -258,30 +257,6 @@ static int sg_io(struct file *file, request_queue_t *q, 
	if (!rq)

		return -ENOMEM;



	if (hdr->iovec_count) {

		const int size = sizeof(struct sg_iovec) * hdr->iovec_count;

		struct sg_iovec *iov;



		iov = kmalloc(size, GFP_KERNEL);

		if (!iov) {

			ret = -ENOMEM;

			goto out;

		}



		if (copy_from_user(iov, hdr->dxferp, size)) {

			kfree(iov);

			ret = -EFAULT;

			goto out;

		}



		ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count);

		kfree(iov);

	} else if (hdr->dxfer_len)

		ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);



	if (ret)

		goto out;



	/*

	 * fill in request structure

	 */
@@ -294,7 +269,6 @@ static int sg_io(struct file *file, request_queue_t *q, 
	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
@@ -309,6 +283,31 @@ static int sg_io(struct file *file, request_queue_t *q, 
	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;



		iov = kmalloc(size, GFP_KERNEL);

		if (!iov) {

			ret = -ENOMEM;

			goto out;

		}



		if (copy_from_user(iov, hdr->dxferp, size)) {

			kfree(iov);

			ret = -EFAULT;

			goto out;

		}



		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);



	if (ret)

		goto out;



	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

drivers/cdrom/cdrom.c

+2 −4
Original line number Diff line number Diff line
@@ -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)

fs/bio.c

+2 −16
Original line number Diff line number Diff line
@@ -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);

}



static void __bio_unmap_user(struct bio *bio)

include/linux/blkdev.h

+4 −3
Original line number Diff line number Diff line
@@ -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 *,