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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-06-10 17:26:42 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-06-10 17:26:42 (GMT) |
commit | 8fade6aff706b2ae3f02864b4023d34b002cd226 (patch) | |
tree | c2c68afd662d5fbaef042e56d91d7813d3a5a9e6 | |
parent | e1f38e2cea199ef2b8e117506fef8abbecbaae5e (diff) | |
parent | 6db40cf047a8723095caf79f5569d21b388d7b31 (diff) | |
download | linux-fsl-qoriq-8fade6aff706b2ae3f02864b4023d34b002cd226.tar.xz |
Merge branch 'for-linus2' of git://git.kernel.dk/linux-2.6-block
* 'for-linus2' of git://git.kernel.dk/linux-2.6-block:
pipe: fix check in "set size" fcntl
pipe: fix pipe buffer resizing
block: remove duplicate BUG_ON() in bd_finish_claiming()
block: bd_start_claiming cleanup
block: bd_start_claiming fix module refcount
-rw-r--r-- | fs/block_dev.c | 72 | ||||
-rw-r--r-- | fs/pipe.c | 20 |
2 files changed, 62 insertions, 30 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 7346c96..99d6af8 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -706,8 +706,13 @@ retry: * @bdev is about to be opened exclusively. Check @bdev can be opened * exclusively and mark that an exclusive open is in progress. Each * successful call to this function must be matched with a call to - * either bd_claim() or bd_abort_claiming(). If this function - * succeeds, the matching bd_claim() is guaranteed to succeed. + * either bd_finish_claiming() or bd_abort_claiming() (which do not + * fail). + * + * This function is used to gain exclusive access to the block device + * without actually causing other exclusive open attempts to fail. It + * should be used when the open sequence itself requires exclusive + * access but may subsequently fail. * * CONTEXT: * Might sleep. @@ -734,6 +739,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, return ERR_PTR(-ENXIO); whole = bdget_disk(disk, 0); + module_put(disk->fops->owner); put_disk(disk); if (!whole) return ERR_PTR(-ENOMEM); @@ -782,15 +788,46 @@ static void bd_abort_claiming(struct block_device *whole, void *holder) __bd_abort_claiming(whole, holder); /* releases bdev_lock */ } +/* increment holders when we have a legitimate claim. requires bdev_lock */ +static void __bd_claim(struct block_device *bdev, struct block_device *whole, + void *holder) +{ + /* note that for a whole device bd_holders + * will be incremented twice, and bd_holder will + * be set to bd_claim before being set to holder + */ + whole->bd_holders++; + whole->bd_holder = bd_claim; + bdev->bd_holders++; + bdev->bd_holder = holder; +} + +/** + * bd_finish_claiming - finish claiming a block device + * @bdev: block device of interest (passed to bd_start_claiming()) + * @whole: whole block device returned by bd_start_claiming() + * @holder: holder trying to claim @bdev + * + * Finish a claiming block started by bd_start_claiming(). + * + * CONTEXT: + * Grabs and releases bdev_lock. + */ +static void bd_finish_claiming(struct block_device *bdev, + struct block_device *whole, void *holder) +{ + spin_lock(&bdev_lock); + BUG_ON(!bd_may_claim(bdev, whole, holder)); + __bd_claim(bdev, whole, holder); + __bd_abort_claiming(whole, holder); /* not actually an abort */ +} + /** * bd_claim - claim a block device * @bdev: block device to claim * @holder: holder trying to claim @bdev * - * Try to claim @bdev which must have been opened successfully. This - * function may be called with or without preceding - * blk_start_claiming(). In the former case, this function is always - * successful and terminates the claiming block. + * Try to claim @bdev which must have been opened successfully. * * CONTEXT: * Might sleep. @@ -806,23 +843,10 @@ int bd_claim(struct block_device *bdev, void *holder) might_sleep(); spin_lock(&bdev_lock); - res = bd_prepare_to_claim(bdev, whole, holder); - if (res == 0) { - /* note that for a whole device bd_holders - * will be incremented twice, and bd_holder will - * be set to bd_claim before being set to holder - */ - whole->bd_holders++; - whole->bd_holder = bd_claim; - bdev->bd_holders++; - bdev->bd_holder = holder; - } - - if (whole->bd_claiming) - __bd_abort_claiming(whole, holder); /* releases bdev_lock */ - else - spin_unlock(&bdev_lock); + if (res == 0) + __bd_claim(bdev, whole, holder); + spin_unlock(&bdev_lock); return res; } @@ -1476,7 +1500,7 @@ static int blkdev_open(struct inode * inode, struct file * filp) if (whole) { if (res == 0) - BUG_ON(bd_claim(bdev, filp) != 0); + bd_finish_claiming(bdev, whole, filp); else bd_abort_claiming(whole, filp); } @@ -1712,7 +1736,7 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) goto out_blkdev_put; - BUG_ON(bd_claim(bdev, holder) != 0); + bd_finish_claiming(bdev, whole, holder); return bdev; out_blkdev_put: @@ -1145,13 +1145,20 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) * and adjust the indexes. */ if (pipe->nrbufs) { - const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1); - const unsigned int head = pipe->nrbufs - tail; + unsigned int tail; + unsigned int head; + tail = pipe->curbuf + pipe->nrbufs; + if (tail < pipe->buffers) + tail = 0; + else + tail &= (pipe->buffers - 1); + + head = pipe->nrbufs - tail; if (head) memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); if (tail) - memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer)); + memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer)); } pipe->curbuf = 0; @@ -1208,12 +1215,13 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) size = round_pipe_size(arg); nr_pages = size >> PAGE_SHIFT; + ret = -EINVAL; + if (!nr_pages) + goto out; + if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { ret = -EPERM; goto out; - } else if (nr_pages < PAGE_SIZE) { - ret = -EINVAL; - goto out; } ret = pipe_set_size(pipe, nr_pages); break; |