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authorChristoph Hellwig <hch@lst.de>2015-01-14 12:42:32 +0300
committerJens Axboe <axboe@fb.com>2015-01-21 00:02:58 +0300
commitb4caecd48005fbed3949dde6c1cb233142fd69e9 (patch)
tree1fdd9b7c15568c79eb3c1ed84a39858ddbcbc88b /fs/romfs
parent97b713ba3ebaa6c8d84c2c720f5468a7c6a6eb4e (diff)
downloadlinux-b4caecd48005fbed3949dde6c1cb233142fd69e9.tar.xz
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>
Diffstat (limited to 'fs/romfs')
-rw-r--r--fs/romfs/mmap-nommu.c10
1 files changed, 10 insertions, 0 deletions
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,
};