target/linux/generic/patches-4.3/903-debloat_direct_io.patch

   1 --- a/fs/Kconfig
   2 +++ b/fs/Kconfig
   3 @@ -68,6 +68,11 @@ config FILE_LOCKING
   4            for filesystems like NFS and for the flock() system
   5            call. Disabling this option saves about 11k.
   6
   7 +config DIRECT_IO
   8 +       bool "Enable O_DIRECT support" if EXPERT
   9 +       depends on BLOCK
  10 +       default y
  11 +
  12  source "fs/notify/Kconfig"
  13
  14  source "fs/quota/Kconfig"
  15 --- a/fs/Makefile
  16 +++ b/fs/Makefile
  17 @@ -14,7 +14,8 @@ obj-y :=      open.o read_write.o file_table.
  18                 stack.o fs_struct.o statfs.o fs_pin.o nsfs.o
  19
  20  ifeq ($(CONFIG_BLOCK),y)
  21 -obj-y +=       buffer.o block_dev.o direct-io.o mpage.o
  22 +obj-y +=       buffer.o block_dev.o mpage.o
  23 +obj-$(CONFIG_DIRECT_IO) += direct-io.o
  24  else
  25  obj-y +=       no-block.o
  26  endif
  27 --- a/include/linux/fs.h
  28 +++ b/include/linux/fs.h
  29 @@ -2695,6 +2695,7 @@ enum {
  30         DIO_SKIP_DIO_COUNT = 0x08,
  31  };
  32
  33 +#ifdef CONFIG_DIRECT_IO
  34  void dio_end_io(struct bio *bio, int error);
  35
  36  ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
  37 @@ -2702,6 +2703,18 @@ ssize_t __blockdev_direct_IO(struct kioc
  38                              loff_t offset, get_block_t get_block,
  39                              dio_iodone_t end_io, dio_submit_t submit_io,
  40                              int flags);
  41 +#else
  42 +static inline void dio_end_io(struct bio *bio, int error)
  43 +{
  44 +}
  45 +static inline ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
  46 +       struct block_device *bdev, struct iov_iter *iter, loff_t offset,
  47 +       get_block_t get_block, dio_iodone_t end_io,
  48 +       dio_submit_t submit_io, int flags)
  49 +{
  50 +       return -EOPNOTSUPP;
  51 +}
  52 +#endif
  53
  54  static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
  55                                          struct inode *inode,
  56 --- a/fs/fcntl.c
  57 +++ b/fs/fcntl.c
  58 @@ -52,8 +52,10 @@ static int setfl(int fd, struct file * f
  59                    arg |= O_NONBLOCK;
  60
  61         if (arg & O_DIRECT) {
  62 +#ifdef CONFIG_DIRECT_IO
  63                 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
  64                         !filp->f_mapping->a_ops->direct_IO)
  65 +#endif
  66                                 return -EINVAL;
  67         }
  68
  69 --- a/fs/open.c
  70 +++ b/fs/open.c
  71 @@ -673,7 +673,9 @@ int open_check_o_direct(struct file *f)
  72  {
  73         /* NB: we're sure to have correct a_ops only after f_op->open */
  74         if (f->f_flags & O_DIRECT) {
  75 +#ifdef CONFIG_DIRECT_IO
  76                 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
  77 +#endif
  78                         return -EINVAL;
  79         }
  80         return 0;