[PATCH] PowerPC: kernel: need return the related error code when failure occurs.

[Chen Gang <gang.chen@asianux.com>]

When error occurs, need return the related error code to let upper
caller know about it.

ppc_md.nvram_size() can return the error code (e.g. core99_nvram_size()
in 'arch/powerpc/platforms/powermac/nvram.c').

And when '*ppos >= size', need return -ESPIPE (Illegal seek)

The original related patch: "f9ce299 [PATCH] powerpc: fix large nvram
access"


Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
 arch/powerpc/kernel/nvram_64.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
index 48fbc2b..db2a636 100644
--- a/arch/powerpc/kernel/nvram_64.c
+++ b/arch/powerpc/kernel/nvram_64.c
@@ -88,10 +88,15 @@ static ssize_t dev_nvram_read(struct file *file, char __user *buf,
 	if (!ppc_md.nvram_size)
 		goto out;
 
-	ret = 0;
 	size = ppc_md.nvram_size();
-	if (*ppos >= size || size < 0)
+	if (size < 0) {
+		ret = size;
 		goto out;
+	}
+	if (*ppos >= size) {
+		ret = -ESPIPE;
+		goto out;
+	}
 
 	count = min_t(size_t, count, size - *ppos);
 	count = min(count, PAGE_SIZE);
-- 
1.7.7.6