From 1e8b33328a5407b447ff80953655a47014a6dcb9 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 29 Nov 2012 10:49:50 -0800 Subject: [PATCH] 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 --- drivers/char/raw.c | 2 +- fs/block_dev.c | 105 ++------------------------------------------- include/linux/fs.h | 4 -- 3 files changed, 5 insertions(+), 106 deletions(-) diff --git a/drivers/char/raw.c b/drivers/char/raw.c index 0bb207eaef2f..54a3a6d09819 100644 --- a/drivers/char/raw.c +++ b/drivers/char/raw.c @@ -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, diff --git a/fs/block_dev.c b/fs/block_dev.c index 1a1e5e3b1eaf..47a949d8a07e 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -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) diff --git a/include/linux/fs.h b/include/linux/fs.h index b33cfc97b9ca..44f288e9726d 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -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, -- 2.20.1