tick/broadcast: Prevent NULL pointer dereference

[uclinux-h8/linux.git] / fs / block_dev.c

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 054ef1b..1982437 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -14,6 +14,7 @@
 #include <linux/device_cgroup.h>
 #include <linux/highmem.h>
 #include <linux/blkdev.h>
+#include <linux/backing-dev.h>
 #include <linux/module.h>
 #include <linux/blkpg.h>
 #include <linux/magic.h>
@@ -42,7 +43,7 @@ static inline struct bdev_inode *BDEV_I(struct inode *inode)
        return container_of(inode, struct bdev_inode, vfs_inode);
 }
 
-inline struct block_device *I_BDEV(struct inode *inode)
+struct block_device *I_BDEV(struct inode *inode)
 {
        return &BDEV_I(inode)->bdev;
 }
@@ -151,6 +152,9 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
        struct file *file = iocb->ki_filp;
        struct inode *inode = file->f_mapping->host;
 
+       if (IS_DAX(inode))
+               return dax_do_io(iocb, inode, iter, offset, blkdev_get_block,
+                               NULL, DIO_SKIP_DIO_COUNT);
        return __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
                                    blkdev_get_block, NULL, NULL,
                                    DIO_SKIP_DIO_COUNT);
@@ -442,6 +446,12 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector,
        long avail;
        const struct block_device_operations *ops = bdev->bd_disk->fops;
 
+       /*
+        * The device driver is allowed to sleep, in order to make the
+        * memory directly accessible.
+        */
+       might_sleep();
+
        if (size < 0)
                return size;
        if (!ops->direct_access)
@@ -546,7 +556,8 @@ static struct file_system_type bd_type = {
        .kill_sb        = kill_anon_super,
 };
 
-static struct super_block *blockdev_superblock __read_mostly;
+struct super_block *blockdev_superblock __read_mostly;
+EXPORT_SYMBOL_GPL(blockdev_superblock);
 
 void __init bdev_cache_init(void)
 {
@@ -687,11 +698,6 @@ static struct block_device *bd_acquire(struct inode *inode)
        return bdev;
 }
 
-int sb_is_blkdev_sb(struct super_block *sb)
-{
-       return sb == blockdev_superblock;
-}
-
 /* Call when you free inode */
 
 void bd_forget(struct inode *inode)
@@ -1173,6 +1179,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                bdev->bd_disk = disk;
                bdev->bd_queue = disk->queue;
                bdev->bd_contains = bdev;
+               bdev->bd_inode->i_flags = disk->fops->direct_access ? S_DAX : 0;
                if (!partno) {
                        ret = -ENXIO;
                        bdev->bd_part = disk_get_part(disk, partno);