From b4caecd48005fbed3949dde6c1cb233142fd69e9 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig <hch@lst.de> Date: Wed, 14 Jan 2015 10:42:32 +0100 Subject: fs: introduce f_op->mmap_capabilities for nommu mmap support Since "BDI: Provide backing device capability information [try #3]" the backing_dev_info structure also provides flags for the kind of mmap operation available in a nommu environment, which is entirely unrelated to it's original purpose. Introduce a new nommu-only file operation to provide this information to the nommu mmap code instead. Splitting this from the backing_dev_info structure allows to remove lots of backing_dev_info instance that aren't otherwise needed, and entirely gets rid of the concept of providing a backing_dev_info for a character device. It also removes the need for the mtd_inodefs filesystem. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Tejun Heo <tj@kernel.org> Acked-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> --- fs/romfs/mmap-nommu.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'fs/romfs') diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c index ea06c7554860..7da9e2153953 100644 --- a/fs/romfs/mmap-nommu.c +++ b/fs/romfs/mmap-nommu.c @@ -70,6 +70,15 @@ static int romfs_mmap(struct file *file, struct vm_area_struct *vma) return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS; } +static unsigned romfs_mmap_capabilities(struct file *file) +{ + struct mtd_info *mtd = file_inode(file)->i_sb->s_mtd; + + if (!mtd) + return NOMMU_MAP_COPY; + return mtd_mmap_capabilities(mtd); +} + const struct file_operations romfs_ro_fops = { .llseek = generic_file_llseek, .read = new_sync_read, @@ -77,4 +86,5 @@ const struct file_operations romfs_ro_fops = { .splice_read = generic_file_splice_read, .mmap = romfs_mmap, .get_unmapped_area = romfs_get_unmapped_area, + .mmap_capabilities = romfs_mmap_capabilities, }; -- cgit v1.2.3