From dc06543ec3d0c1a9d9fdaf050a30c71e2eb64e9c Mon Sep 17 00:00:00 2001
From: Seiji Aguchi <seiji.aguchi@hds.com>
Date: Fri, 11 Jan 2013 18:10:05 +0000
Subject: [PATCH] --- yaml --- r: 352983 b: refs/heads/master c:
 e59310adf5eebce108f78b6c47bb330aae2e1666 h: refs/heads/master i:   352981:
 4fd0f4609b774924d31328feb29931c1f12c0aad   352979:
 0e7bcde455d21d1475f97200de43ea36f4211cd7   352975:
 a27f57ca297ca47fb62b65086c5bbe822c462076 v: v3

---
 [refs]                           |  2 +-
 trunk/drivers/firmware/efivars.c | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 80811ed0742b..6e1bab55c6f5 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9f244e9cfd70c7c0f82d3c92ce772ab2a92d9f64
+refs/heads/master: e59310adf5eebce108f78b6c47bb330aae2e1666
diff --git a/trunk/drivers/firmware/efivars.c b/trunk/drivers/firmware/efivars.c
index 7b1c37497c9a..ef5070d86f88 100644
--- a/trunk/drivers/firmware/efivars.c
+++ b/trunk/drivers/firmware/efivars.c
@@ -1209,7 +1209,16 @@ static int efi_pstore_write(enum pstore_type_id type,
 	u64 storage_space, remaining_space, max_variable_size;
 	efi_status_t status = EFI_NOT_FOUND;
 
-	spin_lock(&efivars->lock);
+	if (pstore_cannot_block_path(reason)) {
+		/*
+		 * If the lock is taken by another cpu in non-blocking path,
+		 * this driver returns without entering firmware to avoid
+		 * hanging up.
+		 */
+		if (!spin_trylock(&efivars->lock))
+			return -EBUSY;
+	} else
+		spin_lock(&efivars->lock);
 
 	/*
 	 * Check if there is a space enough to log.