target/linux/generic/patches-3.6/903-debloat_direct_io.patch

   1 --- a/fs/Kconfig
   2 +++ b/fs/Kconfig
   3 @@ -62,6 +62,11 @@ 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
  19
  20  ifeq ($(CONFIG_BLOCK),y)
  21 -obj-y +=       buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o
  22 +obj-y +=       buffer.o bio.o block_dev.o mpage.o ioprio.o
  23 +obj-$(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 @@ -2632,20 +2632,36 @@ enum {
  30         DIO_SKIP_HOLES  = 0x02,
  31  };
  32
  33 +#ifdef CONFIG_DIRECT_IO
  34  void dio_end_io(struct bio *bio, int error);
  35
  36  ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
  37         struct block_device *bdev, const struct iovec *iov, loff_t offset,
  38         unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
  39         dio_submit_t submit_io, int flags);
  40 +#else
  41 +static inline void dio_end_io(struct bio *bio, int error)
  42 +{
  43 +}
  44 +static inline ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
  45 +       struct block_device *bdev, const struct iovec *iov, loff_t offset,
  46 +       unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
  47 +       dio_submit_t submit_io, int flags)
  48 +{
  49 +       return -EOPNOTSUPP;
  50 +}
  51 +#endif
  52 +
  53
  54  static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
  55                 struct inode *inode, const struct iovec *iov, loff_t offset,
  56                 unsigned long nr_segs, get_block_t get_block)
  57  {
  58 +#ifdef CONFIG_DIRECT_IO
  59         return __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
  60                                     offset, nr_segs, get_block, NULL, NULL,
  61                                     DIO_LOCKING | DIO_SKIP_HOLES);
  62 +#endif
  63  }
  64  #endif
  65
  66 --- a/fs/fcntl.c
  67 +++ b/fs/fcntl.c
  68 @@ -169,8 +169,10 @@ static int setfl(int fd, struct file * f
  69                    arg |= O_NONBLOCK;
  70
  71         if (arg & O_DIRECT) {
  72 +#ifdef CONFIG_DIRECT_IO
  73                 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
  74                         !filp->f_mapping->a_ops->direct_IO)
  75 +#endif
  76                                 return -EINVAL;
  77         }
  78
  79 --- a/fs/open.c
  80 +++ b/fs/open.c
  81 @@ -636,9 +636,12 @@ int open_check_o_direct(struct file *f)
  82  {
  83         /* NB: we're sure to have correct a_ops only after f_op->open */
  84         if (f->f_flags & O_DIRECT) {
  85 +#ifdef CONFIG_DIRECT_IO
  86                 if (!f->f_mapping->a_ops ||
  87                     ((!f->f_mapping->a_ops->direct_IO) &&
  88 -                   (!f->f_mapping->a_ops->get_xip_mem))) {
  89 +                   (!f->f_mapping->a_ops->get_xip_mem)))
  90 +#endif
  91 +               {
  92                         return -EINVAL;
  93                 }
  94         }