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>

diff --git a/drivers/char/raw.c b/drivers/char/raw.c
index 0bb207e..54a3a6d 100644 (file)
--- 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 1a1e5e3..47a949d 100644 (file)
--- 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 b33cfc9..44f288e 100644 (file)
--- 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,