linux-kernel - [PATCH] module/decompress: generate sysfs string at compile time

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Date:   Thu,  1 Sep 2022 00:07:10 +0200
From:   David Disseldorp <ddiss@...e.de>
To:     dmitry.torokhov@...il.com
Cc:     linux-kernel@...r.kernel.org, David Disseldorp <ddiss@...e.de>
Subject: [PATCH] module/decompress: generate sysfs string at compile time

compression_show() before (with noinline):
   0xffffffff810b5ff0 <+0>:     mov    %rdx,%rdi
   0xffffffff810b5ff3 <+3>:     mov    $0xffffffff81b55629,%rsi
   0xffffffff810b5ffa <+10>:    mov    $0xffffffff81b0cde2,%rdx
   0xffffffff810b6001 <+17>:    call   0xffffffff811b8fd0 <sysfs_emit>
   0xffffffff810b6006 <+22>:    cltq
   0xffffffff810b6008 <+24>:    ret

After:
   0xffffffff810b5ff0 <+0>:     mov    $0xffffffff81b0cde2,%rsi
   0xffffffff810b5ff7 <+7>:     mov    %rdx,%rdi
   0xffffffff810b5ffa <+10>:    call   0xffffffff811b8fd0 <sysfs_emit>
   0xffffffff810b5fff <+15>:    cltq
   0xffffffff810b6001 <+17>:    ret

Signed-off-by: David Disseldorp <ddiss@...e.de>
---
 kernel/module/decompress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Feel free to drop the to-be-expected commit message body if desired.

diff --git a/kernel/module/decompress.c b/kernel/module/decompress.c
index 4d0bcb3d9e449..c033572d83f0e 100644
--- a/kernel/module/decompress.c
+++ b/kernel/module/decompress.c
@@ -256,7 +256,7 @@ void module_decompress_cleanup(struct load_info *info)
 static ssize_t compression_show(struct kobject *kobj,
 				struct kobj_attribute *attr, char *buf)
 {
-	return sysfs_emit(buf, "%s\n", __stringify(MODULE_COMPRESSION));
+	return sysfs_emit(buf, __stringify(MODULE_COMPRESSION) "\n");
 }
 
 static struct kobj_attribute module_compression_attr = __ATTR_RO(compression);
-- 
2.35.3