From: Filipe Manana <fdmanana@suse.com>
Date: Wed, 11 Mar 2026 12:07:03 +0000 (+0000)
Subject: btrfs: tag as unlikely branches that call extent_io_tree_panic()
X-Git-Tag: ceph-for-7.1-rc4~321^2~44
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=0f7c10d662ac4fcd749543568d15cd65325feef9;p=ceph-client.git

btrfs: tag as unlikely branches that call extent_io_tree_panic()

It's unexpected to ever call extent_io_tree_panic() so surround with
'unlikely' every if statement condition that leads to it, making it
explicit to a reader and to hint the compiler to potentially generate
better code.

On x86_64, using gcc 14.2.0-19 from Debian, this resulted in a slightly
decrease of the btrfs module's text size.

Before:

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  1999832	 174320	  15592	2189744	 2169b0	fs/btrfs/btrfs.ko

After:

  $ size fs/btrfs/btrfs.ko
     text	   data	    bss	    dec	    hex	filename
  1999768	 174320	  15592	2189680	 216970	fs/btrfs/btrfs.ko

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c
index 68e48b493950..93dca9199249 100644
--- a/fs/btrfs/extent-io-tree.c
+++ b/fs/btrfs/extent-io-tree.c
@@ -696,7 +696,7 @@ hit_next:
 			goto search_again;
 		ret = split_state(tree, state, prealloc, start);
 		prealloc = NULL;
-		if (ret) {
+		if (unlikely(ret)) {
 			extent_io_tree_panic(tree, state, "split", ret);
 			goto out;
 		}
@@ -762,7 +762,7 @@ hit_next:
 		if (!prealloc)
 			goto search_again;
 		ret = split_state(tree, state, prealloc, end + 1);
-		if (ret) {
+		if (unlikely(ret)) {
 			extent_io_tree_panic(tree, state, "split", ret);
 			prealloc = NULL;
 			goto out;
@@ -1203,7 +1203,7 @@ hit_next:
 		if (!prealloc)
 			goto search_again;
 		ret = split_state(tree, state, prealloc, start);
-		if (ret)
+		if (unlikely(ret))
 			extent_io_tree_panic(tree, state, "split", ret);
 
 		prealloc = NULL;
@@ -1293,7 +1293,7 @@ hit_next:
 		if (!prealloc)
 			goto search_again;
 		ret = split_state(tree, state, prealloc, end + 1);
-		if (ret) {
+		if (unlikely(ret)) {
 			extent_io_tree_panic(tree, state, "split", ret);
 			prealloc = NULL;
 			goto out;
@@ -1448,7 +1448,7 @@ hit_next:
 		}
 		ret = split_state(tree, state, prealloc, start);
 		prealloc = NULL;
-		if (ret) {
+		if (unlikely(ret)) {
 			extent_io_tree_panic(tree, state, "split", ret);
 			goto out;
 		}
@@ -1532,7 +1532,7 @@ hit_next:
 		}
 
 		ret = split_state(tree, state, prealloc, end + 1);
-		if (ret) {
+		if (unlikely(ret)) {
 			extent_io_tree_panic(tree, state, "split", ret);
 			prealloc = NULL;
 			goto out;