It's fine to be getting the GEM end working using this easiest way,
and I don't think we'll have a problem with EXPORT_SYMBOL_GPL() on
shmem_file_setup() or something very like it - it just happens that
its current callers are not in loadable modules.
But shmem_getpage() is very much an internal helper function for
mm/shmem.c, and I'm pretty sure we should keep it and its sgp_types
that way: I'll take a look at how you're using it later on, and see
what makes sense to offer instead.
And I don't think you should assume that all GEM users must have
CONFIG_SHMEM=y: we should aim for an interface that mm/tiny_shmem.c
(redirecting to ramfs) can also support. I can believe that GEM and
TINY won't have much intersection, but let's not force that by using
shmem_getpage().
Hugh
quoted text >
> Signed-off-by: Eric Anholt <eric@anholt.net>
> ---
> include/linux/mm.h | 11 +++++++++++
> mm/shmem.c | 17 ++++-------------
> 2 files changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 866a3db..6e54210 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -715,6 +715,17 @@ static inline int shmem_lock(struct file *file, int lock,
> #endif
> struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
>
> +/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
> +enum sgp_type {
> + SGP_READ, /* don't exceed i_size, don't allocate page */
> + SGP_CACHE, /* don't exceed i_size, may allocate page */
> + SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
> + SGP_WRITE, /* may exceed i_size, may allocate page */
> +};
> +
> +int shmem_getpage(struct inode *inode, unsigned long idx,
> + struct page **pagep, enum sgp_type sgp, int *type);
> +
> int shmem_zero_setup(struct vm_area_struct *);
>
> #ifndef CONFIG_MMU
> diff --git a/mm/shmem.c b/mm/shmem.c
> index c1e5a3b..7166ff3 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -77,14 +77,6 @@
> /* Pretend that each entry is of this size in directory's i_size */
> #define BOGO_DIRENT_SIZE 20
>
> -/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
> -enum sgp_type {
> - SGP_READ, /* don't exceed i_size, don't allocate page */
> - SGP_CACHE, /* don't exceed i_size, may allocate page */
> - SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
> - SGP_WRITE, /* may exceed i_size, may allocate page */
> -};
> -
> #ifdef CONFIG_TMPFS
> static unsigned long shmem_default_max_blocks(void)
> {
> @@ -97,9 +89,6 @@ static unsigned long shmem_default_max_inodes(void)
> }
> #endif
>
> -static int shmem_getpage(struct inode *inode, unsigned long idx,
> - struct page **pagep, enum sgp_type sgp, int *type);
> -
> static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
> {
> /*
> @@ -1177,8 +1166,8 @@ static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
> * vm. If we swap it in we mark it dirty since we also free the swap
> * entry since a page cannot live in both the swap and page cache
> */
> -static int shmem_getpage(struct inode *inode, unsigned long idx,
> - struct page **pagep, enum sgp_type sgp, int *type)
> +int shmem_getpage(struct inode *inode, unsigned long idx,
> + struct page **pagep, enum sgp_type sgp, int *type)
> {
> struct address_space *mapping = inode->i_mapping;
> struct shmem_inode_info *info = SHMEM_I(inode);
> @@ -1431,6 +1420,7 @@ failed:
> }
> return error;
> }
> +EXPORT_SYMBOL(shmem_getpage);
>
> static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
> {
> @@ -2582,6 +2572,7 @@ put_memory:
> shmem_unacct_size(flags, size);
> return ERR_PTR(error);
> }
> +EXPORT_SYMBOL(shmem_file_setup);
>
> /**
> * shmem_zero_setup - setup a shared anonymous mapping
> --
> 1.5.6.3
