linux-kernel - [PATCH] pstore: Remove duplicate invoking of persistent_ram

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Message-ID: <1540525277916.97809@xiaomi.com>
Date:   Fri, 26 Oct 2018 03:41:20 +0000
From:   Peng15 Wang 王鹏 <wangpeng15@...omi.com>
To:     "keescook@...omium.org" <keescook@...omium.org>,
        "anton@...msg.org" <anton@...msg.org>,
        "ccross@...roid.com" <ccross@...roid.com>,
        "tony.luck@...el.com" <tony.luck@...el.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] pstore: Remove duplicate invoking of persistent_ram_zap()

From: Peng Wang <wangpeng15@...omi.com>

When initialing przs with invalid data in buffer(no PERSISTENT_RAM_SIG),
function call path is like this:

ramoops_init_prz ->
|
|-> persistent_ram_new -> persistent_ram_post_init -> persistent_ram_zap
|
|--> persistent_ram_zap

As we can see, persistent_ram_zap() is called twice.
We can avoid this by removing it in ramoops_init_prz(),
and only call it in persistent_ram_post_init().

Signed-off-by: Peng Wang <wangpeng15@...omi.com>
---
 fs/pstore/ram.c      | 2 --
 fs/pstore/ram_core.c | 3 +--
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index ffcff6516e89..3f57074a4fab 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -649,8 +649,6 @@ static int ramoops_init_prz(const char *name,
 		return err;
 	}
 
-	persistent_ram_zap(*prz);
-
 	*paddr += sz;
 
 	return 0;
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 12e21f789194..3ef0fd5a7cd5 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -505,15 +505,14 @@ static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
 			pr_debug("found existing buffer, size %zu, start %zu\n",
 				 buffer_size(prz), buffer_start(prz));
 			persistent_ram_save_old(prz);
-			return 0;
 		}
 	} else {
 		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
 			 prz->buffer->sig);
+		prz->buffer->sig = sig;
 	}
 
 	/* Rewind missing or invalid memory area. */
-	prz->buffer->sig = sig;
 	persistent_ram_zap(prz);
 
 	return 0;
-- 
2.19.1