From: Chuansheng Liu <chuansheng.liu@intel.com>
Date: Mon, 17 Sep 2012 17:43:44 +0000 (+0800)
Subject: pstore: Avoid recursive spinlocks in the oops_in_progress case
X-Git-Tag: firefly_0821_release~3680^2~1906^2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=80c9d03c22f13a17df67b4b99a83ed5e9acf6093;p=firefly-linux-kernel-4.4.55.git

pstore: Avoid recursive spinlocks in the oops_in_progress case

Like 8250 driver, when pstore is registered as a console,
to avoid recursive spinlocks when panic happening, change the
spin_lock_irqsave to spin_trylock_irqsave when oops_in_progress
is true.

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
---

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 6c23eab7f76c..a40da07e93d6 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -164,7 +164,13 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
 
 		if (c > psinfo->bufsize)
 			c = psinfo->bufsize;
-		spin_lock_irqsave(&psinfo->buf_lock, flags);
+
+		if (oops_in_progress) {
+			if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
+				break;
+		} else {
+			spin_lock_irqsave(&psinfo->buf_lock, flags);
+		}
 		memcpy(psinfo->buf, s, c);
 		psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
 		spin_unlock_irqrestore(&psinfo->buf_lock, flags);