From: YueHaibing <yuehaibing@xxxxxxxxxx> Subject: kernel/panic.c: taint: fix debugfs_simple_attr.cocci warnings Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE for debugfs files. Semantic patch information: Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file() imposes some significant overhead as compared to DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe(). Generated by: scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci The _unsafe() part suggests that some of them "safeness responsibilities" are now panic.c responsibilities. The patch is OK since panic's clear_warn_once_fops struct file_operations is safe against removal, so we don't have to use otherwise necessary debugfs_file_get()/debugfs_file_put(). [sergey.senozhatsky.work@xxxxxxxxx: changelog addition] Link: http://lkml.kernel.org/r/1545990861-158097-1-git-send-email-yuehaibing@xxxxxxxxxx Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky.work@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxx> Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/kernel/panic.c~taint-fix-debugfs_simple_attrcocci-warnings +++ a/kernel/panic.c @@ -642,16 +642,14 @@ static int clear_warn_once_set(void *dat return 0; } -DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops, - NULL, - clear_warn_once_set, - "%lld\n"); +DEFINE_DEBUGFS_ATTRIBUTE(clear_warn_once_fops, NULL, clear_warn_once_set, + "%lld\n"); static __init int register_warn_debugfs(void) { /* Don't care about failure */ - debugfs_create_file("clear_warn_once", 0200, NULL, - NULL, &clear_warn_once_fops); + debugfs_create_file_unsafe("clear_warn_once", 0200, NULL, NULL, + &clear_warn_once_fops); return 0; } _
