[PATCH] fs/bcachefs: Fix __wait_on_freeing_inode() definition of waitqueue entry

[Ingo Molnar <mingo@kernel.org>]

* NeilBrown <neilb@suse.de> wrote:

> On Wed, 09 Oct 2024, Stephen Rothwell wrote:
> > Hi all,
> > 
> > After merging the tip tree, today's linux-next build (x86_64 allmodconfig)
> > failed like this:
> > 
> > In file included from include/linux/fs.h:6,
> >                  from include/linux/highmem.h:5,
> >                  from include/linux/bvec.h:10,
> >                  from include/linux/blk_types.h:10,
> >                  from include/linux/bio.h:10,
> >                  from fs/bcachefs/bcachefs.h:188,
> >                  from fs/bcachefs/fs.c:4:
> > fs/bcachefs/fs.c: In function '__wait_on_freeing_inode':
> > fs/bcachefs/fs.c:281:31: error: initialization of 'long unsigned int *' from incompatible pointer type 'u32 *' {aka 'unsigned int *'} [-Wincompatible-pointer-types]
> >   281 |         DEFINE_WAIT_BIT(wait, &inode->v.i_state, __I_NEW);
> 
> The fix we want is to replace that line with
>    struct wait_bit_queue_entry wait;
> I should have checked more carefully - sorry.
> 
> I guess we wait for rc3?
> 
> Kent: could you please make that change?  The inode_bit_waitqueue() does
> initialisation equivalent of DEFINE_WAIT_BIT() so you only need the declaration.

Since the breakage was introduced via tip:sched/core, I've applied the fix 
below.

Does this look good to you?

Thanks,

	Ingo

================>
From: Ingo Molnar <mingo@kernel.org>
Date: Wed, 9 Oct 2024 10:00:09 +0200
Subject: [PATCH] fs/bcachefs: Fix __wait_on_freeing_inode() definition of waitqueue entry

The following recent commit made DEFINE_WAIT_BIT() type requirements stricter:

  2382d68d7d43 ("sched: change wake_up_bit() and related function to expect unsigned long *")

.. which results in a build failure:

  > fs/bcachefs/fs.c: In function '__wait_on_freeing_inode':
  > fs/bcachefs/fs.c:281:31: error: initialization of 'long unsigned int *' from incompatible pointer type 'u32 *' {aka 'unsigned int *'} [-Wincompatible-pointer-types]
  >   281 |         DEFINE_WAIT_BIT(wait, &inode->v.i_state, __I_NEW);

Since this code relies on the waitqueue initialization within
inode_bit_waitqueue() anyway, the DEFINE_WAIT_BIT() initialization
is unnecessary - we can just declare a waitqueue entry.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Suggested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 fs/bcachefs/fs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 5bfc26d58270..c410133541ba 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -183,8 +183,9 @@ static void __wait_on_freeing_inode(struct bch_fs *c,
 				    struct bch_inode_info *inode,
 				    subvol_inum inum)
 {
+	struct wait_bit_queue_entry wait;
 	wait_queue_head_t *wq;
-	DEFINE_WAIT_BIT(wait, &inode->v.i_state, __I_NEW);
+
 	wq = inode_bit_waitqueue(&wait, &inode->v, __I_NEW);
 	prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
 	spin_unlock(&inode->v.i_lock);