Previously, alloc_ila_locks() and bucket_table_alloc() call
spin_lock_init() separately, therefore they have two different
lock names and lock class keys. However, after commit b8932817
("ila: Call library function alloc_bucket_locks") they both call
helper alloc_bucket_spinlocks() which now only has one lock
name and lock class key. This causes a few bogus lockdep warnings
as reported by syzbot.

Fix this by making alloc_bucket_locks() a macro and pass declaration
name as lock name and a static lock class key inside the macro.

Fixes: b8932817 ("ila: Call library function alloc_bucket_locks")
Reported-by:  <syzbot+b66a5a554991a8ed027c@syzkaller.appspotmail.com>
Cc: Tom Herbert <tom@quantonium.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

kvmalloc warned about incompatible gfp_mask to catch abusers (mostly
GFP_NOFS) with an intention that this will motivate authors of the code
to fix those.  Linus argues that this just motivates people to do even
more hacks like

	if (gfp == GFP_KERNEL)
		kvmalloc
	else
		kmalloc

I haven't seen this happening much (Linus pointed to bucket_lock special
cases an atomic allocation but my git foo hasn't found much more) but it
is true that we can grow those in future.  Therefore Linus suggested to
simply not fallback to vmalloc for incompatible gfp flags and rather
stick with the kmalloc path.

Link: http://lkml.kernel.org/r/20180601115329.27807-1-mhocko@kernel.org


Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tom Herbert <tom@quantonium.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add two new library functions: alloc_bucket_spinlocks and
free_bucket_spinlocks. These are used to allocate and free an array
of spinlocks that are useful as locks for hash buckets. The interface
specifies the maximum number of spinlocks in the array as well
as a CPU multiplier to derive the number of spinlocks to allocate.
The number allocated is rounded up to a power of two to make the
array amenable to hash lookup.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>