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binfmt_misc: rename load_binfmt_misc() to current_binfmt_misc()

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load_binfmt_misc() is one word swap away from load_misc_binary(),
the binfmt loader it serves. It doesn't load anything, it looks up
the binfmt_misc instance of the caller's user namespace, so name it
after what it returns in the style of current_user_ns() and friends.
Tighten the parent walk into a for loop and fix the stale wording
and typos in the kernel-doc while at it.

Link: https://patch.msgid.link/20260710-work-binfmt_misc-locking-v3-14-a162f7cb58d6@kernel.org
Reviewed-by: Jori Koolstra <jkoolstra@xs4all.nl>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2026-07-10 11:33:15 +02:00
parent f9321c9f95
commit 9c17e93afa
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GPG Key ID: 91C61BC06578DCA2
1 changed files with 11 additions and 13 deletions
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24
fs/binfmt_misc.c
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@ -184,29 +184,27 @@ static void put_binfmt_handler(struct binfmt_misc_entry *e)
}
/**
* load_binfmt_misc - load the binfmt_misc of the caller's user namespace
* current_binfmt_misc - get the binfmt_misc instance of the caller's user namespace
*
* To be called in load_misc_binary() to load the relevant struct binfmt_misc.
* If a user namespace doesn't have its own binfmt_misc mount it can make use
* of its ancestor's binfmt_misc handlers. This mimicks the behavior of
* pre-namespaced binfmt_misc where all registered binfmt_misc handlers where
* available to all user and user namespaces on the system.
* If a user namespace doesn't have its own binfmt_misc mount it uses the
* handlers of its closest ancestor with one. This mimics the behavior of
* pre-namespaced binfmt_misc where all registered handlers were available
* to all users and user namespaces on the system. The init user namespace
* instance is statically set up so the fallback is never reached in
* practice.
*
* Return: the binfmt_misc instance of the caller's user namespace
*/
static struct binfmt_misc *load_binfmt_misc(void)
static struct binfmt_misc *current_binfmt_misc(void)
{
const struct user_namespace *user_ns;
struct binfmt_misc *misc;
user_ns = current_user_ns();
while (user_ns) {
for (user_ns = current_user_ns(); user_ns; user_ns = user_ns->parent) {
/* Pairs with smp_store_release() in bm_fill_super(). */
misc = smp_load_acquire(&user_ns->binfmt_misc);
if (misc)
return misc;
user_ns = user_ns->parent;
}
return &init_binfmt_misc;
@ -222,7 +220,7 @@ static int load_misc_binary(struct linux_binprm *bprm)
int retval = -ENOEXEC;
struct binfmt_misc *misc;
misc = load_binfmt_misc();
misc = current_binfmt_misc();
if (!READ_ONCE(misc->enabled))
return retval;
@ -977,7 +975,7 @@ static int bm_fill_super(struct super_block *sb, struct fs_context *fc)
INIT_HLIST_HEAD(&misc->entries);
spin_lock_init(&misc->entries_lock);
/* Pairs with smp_load_acquire() in load_binfmt_misc(). */
/* Pairs with smp_load_acquire() in current_binfmt_misc(). */
smp_store_release(&user_ns->binfmt_misc, misc);
}