linux-kernel - [PATCH V2] powerpc/setup_64: use DEFINE_DEBUGFS_ATTRIBUTE to define fops_rfi

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Message-ID: <20191219111812.180386-1-chenzhou10@huawei.com>
Date:   Thu, 19 Dec 2019 19:18:12 +0800
From:   Chen Zhou <chenzhou10@...wei.com>
To:     <benh@...nel.crashing.org>, <paulus@...ba.org>,
        <mpe@...erman.id.au>
CC:     <linuxppc-dev@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
        <chenzhou10@...wei.com>
Subject: [PATCH V2] powerpc/setup_64: use DEFINE_DEBUGFS_ATTRIBUTE to define fops_rfi_flush

Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE for
debugfs files.

In order to protect against file removal races, debugfs files created via
debugfs_create_file() are wrapped by a struct file_operations at their
opening.

If the original struct file_operations is known to be safe against removal
races already, the proxy creation may be bypassed by creating the files
using DEFINE_DEBUGFS_ATTRIBUTE() and debugfs_create_file_unsafe().

Signed-off-by: Chen Zhou <chenzhou10@...wei.com>
---
Changes since v1:
- modify commit message.

 arch/powerpc/kernel/setup_64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 6104917..4b9fbb2 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -956,11 +956,11 @@ static int rfi_flush_get(void *data, u64 *val)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n");
 
 static __init int rfi_flush_debugfs_init(void)
 {
-	debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush);
+	debugfs_create_file_unsafe("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush);
 	return 0;
 }
 device_initcall(rfi_flush_debugfs_init);
-- 
2.7.4