treewide: refresh kmalloc_obj() conversionsgrafted

This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci

This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.

Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.

Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/Documentation/filesystems/automount-support.rst b/Documentation/filesystems/automount-support.rst
new file mode 100644
index 000000000..430f0b407
--- /dev/null
+++ b/Documentation/filesystems/automount-support.rst
@@ -0,0 +1,98 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+Automount Support
+=================
+
+
+Support is available for filesystems that wish to do automounting
+support (such as kAFS which can be found in fs/afs/ and NFS in
+fs/nfs/). This facility includes allowing in-kernel mounts to be
+performed and mountpoint degradation to be requested. The latter can
+also be requested by userspace.
+
+
+In-Kernel Automounting
+======================
+
+See section "Mount Traps" of  Documentation/filesystems/autofs.rst
+
+Then from userspace, you can just do something like::
+
+	[root@andromeda root]# mount -t afs \#root.afs. /afs
+	[root@andromeda root]# ls /afs
+	asd  cambridge  cambridge.redhat.com  grand.central.org
+	[root@andromeda root]# ls /afs/cambridge
+	afsdoc
+	[root@andromeda root]# ls /afs/cambridge/afsdoc/
+	ChangeLog  html  LICENSE  pdf  RELNOTES-1.2.2
+
+And then if you look in the mountpoint catalogue, you'll see something like::
+
+	[root@andromeda root]# cat /proc/mounts
+	...
+	#root.afs. /afs afs rw 0 0
+	#root.cell. /afs/cambridge.redhat.com afs rw 0 0
+	#afsdoc. /afs/cambridge.redhat.com/afsdoc afs rw 0 0
+
+
+Automatic Mountpoint Expiry
+===========================
+
+Automatic expiration of mountpoints is easy, provided you've mounted the
+mountpoint to be expired in the automounting procedure outlined separately.
+
+To do expiration, you need to follow these steps:
+
+ (1) Create at least one list off which the vfsmounts to be expired can be
+     hung.
+
+ (2) When a new mountpoint is created in the ->d_automount method, add
+     the mnt to the list using mnt_set_expiry()::
+
+             mnt_set_expiry(newmnt, &afs_vfsmounts);
+
+ (3) When you want mountpoints to be expired, call mark_mounts_for_expiry()
+     with a pointer to this list. This will process the list, marking every
+     vfsmount thereon for potential expiry on the next call.
+
+     If a vfsmount was already flagged for expiry, and if its usage count is 1
+     (it's only referenced by its parent vfsmount), then it will be deleted
+     from the namespace and thrown away (effectively unmounted).
+
+     It may prove simplest to simply call this at regular intervals, using
+     some sort of timed event to drive it.
+
+The expiration flag is cleared by calls to mntput. This means that expiration
+will only happen on the second expiration request after the last time the
+mountpoint was accessed.
+
+If a mountpoint is moved, it gets removed from the expiration list. If a bind
+mount is made on an expirable mount, the new vfsmount will not be on the
+expiration list and will not expire.
+
+If a namespace is copied, all mountpoints contained therein will be copied,
+and the copies of those that are on an expiration list will be added to the
+same expiration list.
+
+
+Userspace Driven Expiry
+=======================
+
+As an alternative, it is possible for userspace to request expiry of any
+mountpoint (though some will be rejected - the current process's idea of the
+rootfs for example). It does this by passing the MNT_EXPIRE flag to
+umount(). This flag is considered incompatible with MNT_FORCE and MNT_DETACH.
+
+If the mountpoint in question is in referenced by something other than
+umount() or its parent mountpoint, an EBUSY error will be returned and the
+mountpoint will not be marked for expiration or unmounted.
+
+If the mountpoint was not already marked for expiry at that time, an EAGAIN
+error will be given and it won't be unmounted.
+
+Otherwise if it was already marked and it wasn't referenced, unmounting will
+take place as usual.
+
+Again, the expiration flag is cleared every time anything other than umount()
+looks at a mountpoint.