diff options
Diffstat (limited to 'fs/backing-file.c')
| -rw-r--r-- | fs/backing-file.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/fs/backing-file.c b/fs/backing-file.c index ddd35c1d6c71..a681f38d84d8 100644 --- a/fs/backing-file.c +++ b/fs/backing-file.c @@ -11,6 +11,7 @@ #include <linux/fs.h> #include <linux/backing-file.h> #include <linux/splice.h> +#include <linux/mm.h> #include "internal.h" @@ -296,6 +297,32 @@ ssize_t backing_file_splice_write(struct pipe_inode_info *pipe, } EXPORT_SYMBOL_GPL(backing_file_splice_write); +int backing_file_mmap(struct file *file, struct vm_area_struct *vma, + struct backing_file_ctx *ctx) +{ + const struct cred *old_cred; + int ret; + + if (WARN_ON_ONCE(!(file->f_mode & FMODE_BACKING)) || + WARN_ON_ONCE(ctx->user_file != vma->vm_file)) + return -EIO; + + if (!file->f_op->mmap) + return -ENODEV; + + vma_set_file(vma, file); + + old_cred = override_creds(ctx->cred); + ret = call_mmap(vma->vm_file, vma); + revert_creds(old_cred); + + if (ctx->accessed) + ctx->accessed(ctx->user_file); + + return ret; +} +EXPORT_SYMBOL_GPL(backing_file_mmap); + static int __init backing_aio_init(void) { backing_aio_cachep = kmem_cache_create("backing_aio", |