Permalink
Browse files

[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: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
  • Loading branch information...
Mike Christie Jens Axboe
Mike Christie authored and Jens Axboe committed Dec 1, 2006
1 parent ad2d722 commit 0e75f9063f5c55fb0b0b546a7c356f8ec186825e
Showing with 160 additions and 90 deletions.
  1. +126 −40 block/ll_rw_blk.c
  2. +26 −27 block/scsi_ioctl.c
  3. +2 −4 drivers/cdrom/cdrom.c
  4. +2 −16 fs/bio.c
  5. +4 −3 include/linux/blkdev.h
View
@@ -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;
@@ -2418,34 +2498,42 @@ 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;
}
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;
}
View
@@ -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
View
@@ -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)
View
@@ -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)
View
@@ -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 *,

0 comments on commit 0e75f90

Please sign in to comment.