target/linux/generic/patches-4.9/903-debloat_direct_io.patch

   1 --- a/fs/Kconfig
   2 +++ b/fs/Kconfig
   3 @@ -97,6 +97,11 @@ config MANDATORY_FILE_LOCKING
   4
   5  source "fs/crypto/Kconfig"
   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 @@ -2852,6 +2852,7 @@ 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 @@ -2859,6 +2860,20 @@ ssize_t __blockdev_direct_IO(struct kioc
  38                              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
  46 +ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
  47 +                            struct block_device *bdev, struct iov_iter *iter,
  48 +                            get_block_t get_block,
  49 +                            dio_iodone_t end_io, dio_submit_t submit_io,
  50 +                            int flags)
  51 +{
  52 +       return -EOPNOTSUPP;
  53 +}
  54 +#endif
  55
  56  static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
  57                                          struct inode *inode,
  58 --- a/fs/fcntl.c
  59 +++ b/fs/fcntl.c
  60 @@ -53,8 +53,10 @@ static int setfl(int fd, struct file * f
  61
  62         /* Pipe packetized mode is controlled by O_DIRECT flag */
  63         if (!S_ISFIFO(filp->f_inode->i_mode) && (arg & O_DIRECT)) {
  64 +#ifdef CONFIG_DIRECT_IO
  65                 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
  66                         !filp->f_mapping->a_ops->direct_IO)
  67 +#endif
  68                                 return -EINVAL;
  69         }
  70
  71 --- a/fs/open.c
  72 +++ b/fs/open.c
  73 @@ -690,7 +690,9 @@ int open_check_o_direct(struct file *f)
  74  {
  75         /* NB: we're sure to have correct a_ops only after f_op->open */
  76         if (f->f_flags & O_DIRECT) {
  77 +#ifdef CONFIG_DIRECT_IO
  78                 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
  79 +#endif
  80                         return -EINVAL;
  81         }
  82         return 0;