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>
This commit is contained in:
Christoph Hellwig 2015-01-14 10:42:32 +01:00 committed by Jens Axboe
parent 97b713ba3e
commit b4caecd480
32 changed files with 169 additions and 346 deletions

View file

@ -732,8 +732,6 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[], /* subdevices to c
concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
concat->subdev[0] = subdev[0];
for (i = 1; i < num_devs; i++) {
@ -761,14 +759,6 @@ struct mtd_info *mtd_concat_create(struct mtd_info *subdev[], /* subdevices to c
subdev[i]->flags & MTD_WRITEABLE;
}
/* only permit direct mapping if the BDIs are all the same
* - copy-mapping is still permitted
*/
if (concat->mtd.backing_dev_info !=
subdev[i]->backing_dev_info)
concat->mtd.backing_dev_info =
&default_backing_dev_info;
concat->mtd.size += subdev[i]->size;
concat->mtd.ecc_stats.badblocks +=
subdev[i]->ecc_stats.badblocks;