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>
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 5356395..55fa27e 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -49,7 +49,6 @@
*/
struct mtd_file_info {
struct mtd_info *mtd;
- struct inode *ino;
enum mtd_file_modes mode;
};
@@ -59,10 +58,6 @@
return fixed_size_llseek(file, offset, orig, mfi->mtd->size);
}
-static int count;
-static struct vfsmount *mnt;
-static struct file_system_type mtd_inodefs_type;
-
static int mtdchar_open(struct inode *inode, struct file *file)
{
int minor = iminor(inode);
@@ -70,7 +65,6 @@
int ret = 0;
struct mtd_info *mtd;
struct mtd_file_info *mfi;
- struct inode *mtd_ino;
pr_debug("MTD_open\n");
@@ -78,10 +72,6 @@
if ((file->f_mode & FMODE_WRITE) && (minor & 1))
return -EACCES;
- ret = simple_pin_fs(&mtd_inodefs_type, &mnt, &count);
- if (ret)
- return ret;
-
mutex_lock(&mtd_mutex);
mtd = get_mtd_device(NULL, devnum);
@@ -95,43 +85,26 @@
goto out1;
}
- mtd_ino = iget_locked(mnt->mnt_sb, devnum);
- if (!mtd_ino) {
- ret = -ENOMEM;
- goto out1;
- }
- if (mtd_ino->i_state & I_NEW) {
- mtd_ino->i_private = mtd;
- mtd_ino->i_mode = S_IFCHR;
- mtd_ino->i_data.backing_dev_info = mtd->backing_dev_info;
- unlock_new_inode(mtd_ino);
- }
- file->f_mapping = mtd_ino->i_mapping;
-
/* You can't open it RW if it's not a writeable device */
if ((file->f_mode & FMODE_WRITE) && !(mtd->flags & MTD_WRITEABLE)) {
ret = -EACCES;
- goto out2;
+ goto out1;
}
mfi = kzalloc(sizeof(*mfi), GFP_KERNEL);
if (!mfi) {
ret = -ENOMEM;
- goto out2;
+ goto out1;
}
- mfi->ino = mtd_ino;
mfi->mtd = mtd;
file->private_data = mfi;
mutex_unlock(&mtd_mutex);
return 0;
-out2:
- iput(mtd_ino);
out1:
put_mtd_device(mtd);
out:
mutex_unlock(&mtd_mutex);
- simple_release_fs(&mnt, &count);
return ret;
} /* mtdchar_open */
@@ -148,12 +121,9 @@
if ((file->f_mode & FMODE_WRITE))
mtd_sync(mtd);
- iput(mfi->ino);
-
put_mtd_device(mtd);
file->private_data = NULL;
kfree(mfi);
- simple_release_fs(&mnt, &count);
return 0;
} /* mtdchar_close */
@@ -1117,6 +1087,13 @@
ret = mtd_get_unmapped_area(mtd, len, offset, flags);
return ret == -EOPNOTSUPP ? -ENODEV : ret;
}
+
+static unsigned mtdchar_mmap_capabilities(struct file *file)
+{
+ struct mtd_file_info *mfi = file->private_data;
+
+ return mtd_mmap_capabilities(mfi->mtd);
+}
#endif
/*
@@ -1160,27 +1137,10 @@
.mmap = mtdchar_mmap,
#ifndef CONFIG_MMU
.get_unmapped_area = mtdchar_get_unmapped_area,
+ .mmap_capabilities = mtdchar_mmap_capabilities,
#endif
};
-static const struct super_operations mtd_ops = {
- .drop_inode = generic_delete_inode,
- .statfs = simple_statfs,
-};
-
-static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data)
-{
- return mount_pseudo(fs_type, "mtd_inode:", &mtd_ops, NULL, MTD_INODE_FS_MAGIC);
-}
-
-static struct file_system_type mtd_inodefs_type = {
- .name = "mtd_inodefs",
- .mount = mtd_inodefs_mount,
- .kill_sb = kill_anon_super,
-};
-MODULE_ALIAS_FS("mtd_inodefs");
-
int __init init_mtdchar(void)
{
int ret;
@@ -1193,23 +1153,11 @@
return ret;
}
- ret = register_filesystem(&mtd_inodefs_type);
- if (ret) {
- pr_err("Can't register mtd_inodefs filesystem, error %d\n",
- ret);
- goto err_unregister_chdev;
- }
-
- return ret;
-
-err_unregister_chdev:
- __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
return ret;
}
void __exit cleanup_mtdchar(void)
{
- unregister_filesystem(&mtd_inodefs_type);
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
}