diff mbox series

[05/21] btrfs: remove the refcount warning/check at btrfs_put_delayed_ref()

Message ID d67dc2650159fbcbe0cafc5bb9ab390aa985ce11.1694174371.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: updates to delayed refs accounting and space reservation | expand

Commit Message

Filipe Manana Sept. 8, 2023, 12:09 p.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

At btrfs_put_delayed_ref(), it's pointless to have a WARN_ON() to check if
the refcount of the delayed ref is zero. Such check is already done by the
refcount_t module and refcount_dec_and_test(), which loudly complains if
we try to decrement a reference count that is currently 0.

The WARN_ON() dates back to the time when used a regular atomic_t type
for the reference counter, before we switched to the refcount_t type.
The main goal of the refcount_t type/module is precisely to catch such
types of bugs and loudly complain if they happen.

This also reduces a bit the module's text size.
Before this change:

   $ size fs/btrfs/btrfs.ko
      text	   data	    bss	    dec	    hex	filename
   1612483	 167145	  16864	1796492	 1b698c	fs/btrfs/btrfs.ko

After this change:

   $ size fs/btrfs/btrfs.ko
      text	   data	    bss	    dec	    hex	filename
   1612371	 167073	  16864	1796308	 1b68d4	fs/btrfs/btrfs.ko

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/delayed-ref.h | 1 -
 1 file changed, 1 deletion(-)

Comments

Josef Bacik Sept. 8, 2023, 3 p.m. UTC | #1 
On Fri, Sep 08, 2023 at 01:09:07PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> At btrfs_put_delayed_ref(), it's pointless to have a WARN_ON() to check if
> the refcount of the delayed ref is zero. Such check is already done by the
> refcount_t module and refcount_dec_and_test(), which loudly complains if
> we try to decrement a reference count that is currently 0.
> 
> The WARN_ON() dates back to the time when used a regular atomic_t type
> for the reference counter, before we switched to the refcount_t type.
> The main goal of the refcount_t type/module is precisely to catch such
> types of bugs and loudly complain if they happen.
> 
> This also reduces a bit the module's text size.
> Before this change:
> 
>    $ size fs/btrfs/btrfs.ko
>       text	   data	    bss	    dec	    hex	filename
>    1612483	 167145	  16864	1796492	 1b698c	fs/btrfs/btrfs.ko
> 
> After this change:
> 
>    $ size fs/btrfs/btrfs.ko
>       text	   data	    bss	    dec	    hex	filename
>    1612371	 167073	  16864	1796308	 1b68d4	fs/btrfs/btrfs.ko
> 
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef
diff mbox series

Patch

diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index fd9bf2b709c0..46a1421cd99d 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -338,7 +338,6 @@  btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
 
 static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
 {
-	WARN_ON(refcount_read(&ref->refs) == 0);
 	if (refcount_dec_and_test(&ref->refs)) {
 		WARN_ON(!RB_EMPTY_NODE(&ref->ref_node));
 		switch (ref->type) {