Commit 4169680e authored Mar 07, 2019 by YueHaibing Committed by Linus Torvalds Mar 07, 2019

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@gmail.com: changelog addition]
Link: http://lkml.kernel.org/r/1545990861-158097-1-git-send-email-yuehaibing@huawei.com


Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c461aed3

kernel/panic.c

+4 −6

Original line number	Diff line number	Diff line
		@@ -642,16 +642,14 @@ static int clear_warn_once_set(void *data, u64 val)
		return 0;
		}

		DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops,
		NULL,
		clear_warn_once_set,
		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;
		}

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