blockdev: remove bd_block_size_semaphore again

This reverts the block-device direct access code to the previous
unlocked code, now that fs/buffer.c no longer needs external locking.

With this, fs/block_dev.c is back to the original version, apart from a
whitespace cleanup that I didn't want to revert.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2012-11-29 10:49:50 -08:00
parent 45bce8f3e3
commit 1e8b33328a
3 changed files with 5 additions and 106 deletions

View file

@ -285,7 +285,7 @@ static long raw_ctl_compat_ioctl(struct file *file, unsigned int cmd,
static const struct file_operations raw_fops = {
.read = do_sync_read,
.aio_read = blkdev_aio_read,
.aio_read = generic_file_aio_read,
.write = do_sync_write,
.aio_write = blkdev_aio_write,
.fsync = blkdev_fsync,

View file

@ -116,8 +116,6 @@ EXPORT_SYMBOL(invalidate_bdev);
int set_blocksize(struct block_device *bdev, int size)
{
struct address_space *mapping;
/* Size must be a power of two, and between 512 and PAGE_SIZE */
if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
return -EINVAL;
@ -126,19 +124,6 @@ int set_blocksize(struct block_device *bdev, int size)
if (size < bdev_logical_block_size(bdev))
return -EINVAL;
/* Prevent starting I/O or mapping the device */
percpu_down_write(&bdev->bd_block_size_semaphore);
/* Check that the block device is not memory mapped */
mapping = bdev->bd_inode->i_mapping;
mutex_lock(&mapping->i_mmap_mutex);
if (mapping_mapped(mapping)) {
mutex_unlock(&mapping->i_mmap_mutex);
percpu_up_write(&bdev->bd_block_size_semaphore);
return -EBUSY;
}
mutex_unlock(&mapping->i_mmap_mutex);
/* Don't change the size if it is same as current */
if (bdev->bd_block_size != size) {
sync_blockdev(bdev);
@ -146,9 +131,6 @@ int set_blocksize(struct block_device *bdev, int size)
bdev->bd_inode->i_blkbits = blksize_bits(size);
kill_bdev(bdev);
}
percpu_up_write(&bdev->bd_block_size_semaphore);
return 0;
}
@ -459,12 +441,6 @@ static struct inode *bdev_alloc_inode(struct super_block *sb)
struct bdev_inode *ei = kmem_cache_alloc(bdev_cachep, GFP_KERNEL);
if (!ei)
return NULL;
if (unlikely(percpu_init_rwsem(&ei->bdev.bd_block_size_semaphore))) {
kmem_cache_free(bdev_cachep, ei);
return NULL;
}
return &ei->vfs_inode;
}
@ -473,8 +449,6 @@ static void bdev_i_callback(struct rcu_head *head)
struct inode *inode = container_of(head, struct inode, i_rcu);
struct bdev_inode *bdi = BDEV_I(inode);
percpu_free_rwsem(&bdi->bdev.bd_block_size_semaphore);
kmem_cache_free(bdev_cachep, bdi);
}
@ -1593,22 +1567,6 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
return blkdev_ioctl(bdev, mode, cmd, arg);
}
ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
ssize_t ret;
struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
percpu_down_read(&bdev->bd_block_size_semaphore);
ret = generic_file_aio_read(iocb, iov, nr_segs, pos);
percpu_up_read(&bdev->bd_block_size_semaphore);
return ret;
}
EXPORT_SYMBOL_GPL(blkdev_aio_read);
/*
* Write data to the block device. Only intended for the block device itself
* and the raw driver which basically is a fake block device.
@ -1620,16 +1578,12 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct block_device *bdev = I_BDEV(file->f_mapping->host);
struct blk_plug plug;
ssize_t ret;
BUG_ON(iocb->ki_pos != pos);
blk_start_plug(&plug);
percpu_down_read(&bdev->bd_block_size_semaphore);
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
if (ret > 0 || ret == -EIOCBQUEUED) {
ssize_t err;
@ -1638,62 +1592,11 @@ ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
if (err < 0 && ret > 0)
ret = err;
}
percpu_up_read(&bdev->bd_block_size_semaphore);
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL_GPL(blkdev_aio_write);
static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
{
int ret;
struct block_device *bdev = I_BDEV(file->f_mapping->host);
percpu_down_read(&bdev->bd_block_size_semaphore);
ret = generic_file_mmap(file, vma);
percpu_up_read(&bdev->bd_block_size_semaphore);
return ret;
}
static ssize_t blkdev_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
ssize_t ret;
struct block_device *bdev = I_BDEV(file->f_mapping->host);
percpu_down_read(&bdev->bd_block_size_semaphore);
ret = generic_file_splice_read(file, ppos, pipe, len, flags);
percpu_up_read(&bdev->bd_block_size_semaphore);
return ret;
}
static ssize_t blkdev_splice_write(struct pipe_inode_info *pipe,
struct file *file, loff_t *ppos, size_t len,
unsigned int flags)
{
ssize_t ret;
struct block_device *bdev = I_BDEV(file->f_mapping->host);
percpu_down_read(&bdev->bd_block_size_semaphore);
ret = generic_file_splice_write(pipe, file, ppos, len, flags);
percpu_up_read(&bdev->bd_block_size_semaphore);
return ret;
}
/*
* Try to release a page associated with block device when the system
* is under memory pressure.
@ -1724,16 +1627,16 @@ const struct file_operations def_blk_fops = {
.llseek = block_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = blkdev_aio_read,
.aio_read = generic_file_aio_read,
.aio_write = blkdev_aio_write,
.mmap = blkdev_mmap,
.mmap = generic_file_mmap,
.fsync = blkdev_fsync,
.unlocked_ioctl = block_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = compat_blkdev_ioctl,
#endif
.splice_read = blkdev_splice_read,
.splice_write = blkdev_splice_write,
.splice_read = generic_file_splice_read,
.splice_write = generic_file_splice_write,
};
int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg)

View file

@ -462,8 +462,6 @@ struct block_device {
int bd_fsfreeze_count;
/* Mutex for freeze */
struct mutex bd_fsfreeze_mutex;
/* A semaphore that prevents I/O while block size is being changed */
struct percpu_rw_semaphore bd_block_size_semaphore;
};
/*
@ -2379,8 +2377,6 @@ extern int generic_segment_checks(const struct iovec *iov,
unsigned long *nr_segs, size_t *count, int access_flags);
/* fs/block_dev.c */
extern ssize_t blkdev_aio_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos);
extern ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos);
extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,