document alloc_file() changes

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2018-07-09 19:20:08 -04:00
parent ee1904ba44
commit 5014c2f378

View file

@ -610,3 +610,15 @@ in your dentry operations instead.
value for 'called finish_no_open(), open it yourself' case has become
0, not 1. Since finish_no_open() itself is returning 0 now, that part
does not need any changes in ->atomic_open() instances.
--
[mandatory]
alloc_file() has become static now; two wrappers are to be used instead.
alloc_file_pseudo(inode, vfsmount, name, flags, ops) is for the cases
when dentry needs to be created; that's the majority of old alloc_file()
users. Calling conventions: on success a reference to new struct file
is returned and callers reference to inode is subsumed by that. On
failure, ERR_PTR() is returned and no caller's references are affected,
so the caller needs to drop the inode reference it held.
alloc_file_clone(file, flags, ops) does not affect any caller's references.
On success you get a new struct file sharing the mount/dentry with the
original, on failure - ERR_PTR().