[PATCH] pstore: avoid recursive spinlocks in the oops_in_progress case

[Chuansheng Liu <chuansheng.liu@intel.com>]

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>
---
 fs/pstore/platform.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 29996e8..cbcb5fc 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -164,7 +164,12 @@ 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);
-- 
1.7.0.4