struct filename: use names_cachep only for getname() and friends

        Instances of struct filename come from names_cachep (via
__getname()).  That is done by getname_flags() and getname_kernel()
and these two are the main callers of __getname().  However, there are
other callers that simply want to allocate PATH_MAX bytes for uses that
have nothing to do with struct filename.

	We want saner allocation rules for long pathnames, so that struct
filename would *always* come from names_cachep, with the out-of-line
pathname getting kmalloc'ed.  For that we need to be able to change the
size of objects allocated by getname_flags()/getname_kernel().

	That requires the rest of __getname() users to stop using
names_cachep; we could explicitly switch all of those to kmalloc(),
but that would cause quite a bit of noise.  So the plan is to switch
getname_...() to new helpers and turn __getname() into a wrapper for
kmalloc().  Remaining __getname() users could be converted to explicit
kmalloc() at leisure, hopefully along with figuring out what size do
they really want - PATH_MAX is an overkill for some of them, used out
of laziness ("we have a convenient helper that does 4K allocations and
that's large enough, let's use it").

	As a side benefit, names_cachep is no longer used outside
of fs/namei.c, so we can move it there and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 1 insertions, 7 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index dc2fff4811d1..cf865c12cdf9 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3290,10 +3290,6 @@ static void __init dcache_init(void)
 	runtime_const_init(ptr, dentry_hashtable);
 }
 
-/* SLAB cache for __getname() consumers */
-struct kmem_cache *names_cachep __ro_after_init;
-EXPORT_SYMBOL(names_cachep);
-
 void __init vfs_caches_init_early(void)
 {
 	int i;
@@ -3307,9 +3303,7 @@ void __init vfs_caches_init_early(void)
 
 void __init vfs_caches_init(void)
 {
-	names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0,
-			SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL);
-
+	filename_init();
 	dcache_init();
 	inode_init();
 	files_init();