[PATCH] btrfs: make sure report_eb_range() is not inlined

[fdmanana@kernel.org]

From: Filipe Manana <fdmanana@suse.com>

If report_rb_range() is inlined into its single caller (check_eb_range()),
we end up with a larger module size, which is undesirable and does not
provide any advantage since this code is for a cold path which we don't
expect to ever hit.

Add the noinline attribute to report_rb_range() and while at it also make
it return void as it always returns true.

Before this change (with gcc 14.2.0-19 from Debian):

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  2018267	 176232	  15592	2210091	 21b92b	fs/btrfs/btrfs.ko

After this change:

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  2017835	 176048	  15592	2209475	 21b6c3	fs/btrfs/btrfs.ko

Also, replacing the noinline with __cold, yields slighty worse results:

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  2017889	 176048	  15592	2209529	 21b6f9	fs/btrfs/btrfs.ko

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/extent_io.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 3d20e2d418ac..b6a92c9a17cf 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3976,15 +3976,14 @@ int read_extent_buffer_pages(struct extent_buffer *eb, int mirror_num,
 	return 0;
 }
 
-static bool report_eb_range(const struct extent_buffer *eb, unsigned long start,
-			    unsigned long len)
+/* Never inlined to decrease code size, as this is called in a cold path. */
+static noinline void report_eb_range(const struct extent_buffer *eb,
+				     unsigned long start, unsigned long len)
 {
 	btrfs_warn(eb->fs_info,
 		"access to eb bytenr %llu len %u out of range start %lu len %lu",
 		eb->start, eb->len, start, len);
 	DEBUG_WARN();
-
-	return true;
 }
 
 /*
@@ -4000,8 +3999,10 @@ static inline bool check_eb_range(const struct extent_buffer *eb,
 	unsigned long offset;
 
 	/* start, start + len should not go beyond eb->len nor overflow */
-	if (unlikely(check_add_overflow(start, len, &offset) || offset > eb->len))
-		return report_eb_range(eb, start, len);
+	if (unlikely(check_add_overflow(start, len, &offset) || offset > eb->len)) {
+		report_eb_range(eb, start, len);
+		return true;
+	}
 
 	return false;
 }
-- 
2.47.2