[PATCH 1/5] btrfs: remove redundant check in up check_setget_bounds

[David Sterba <dsterba@suse.com>]

There are two separate checks in the bounds checker, the first one being
a special case of the second. As this function is performance critical
due to checking access to any eb member, reducing the size can slightly
improve performance.

On a release build on x86_64 the helper is completely inlined so the
function call overhead is also gone.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/struct-funcs.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/struct-funcs.c b/fs/btrfs/struct-funcs.c
index f429256f56db..12455b2b41de 100644
--- a/fs/btrfs/struct-funcs.c
+++ b/fs/btrfs/struct-funcs.c
@@ -12,15 +12,10 @@ static bool check_setget_bounds(const struct extent_buffer *eb,
 {
 	const unsigned long member_offset = (unsigned long)ptr + off;
 
-	if (member_offset > eb->len) {
+	if (unlikely(member_offset + size > eb->len)) {
 		btrfs_warn(eb->fs_info,
-	"bad eb member start: ptr 0x%lx start %llu member offset %lu size %d",
-			(unsigned long)ptr, eb->start, member_offset, size);
-		return false;
-	}
-	if (member_offset + size > eb->len) {
-		btrfs_warn(eb->fs_info,
-	"bad eb member end: ptr 0x%lx start %llu member offset %lu size %d",
+		"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
+			(member_offset > eb->len ? "start" : "end"),
 			(unsigned long)ptr, eb->start, member_offset, size);
 		return false;
 	}
-- 
2.34.1