Patchwork PowerPC: kernel: need return the related error code when failure occurs.

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Submitter Chen Gang
Date May 21, 2013, 5:48 a.m.
Message ID <519B0ACA.6090008@asianux.com>
Download mbox | patch
Permalink /patch/245184/
State Rejected
Headers show

Comments

Chen Gang - May 21, 2013, 5:48 a.m.
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(-)
Paul Mackerras - May 21, 2013, 8:10 a.m.
On Tue, May 21, 2013 at 01:48:58PM +0800, Chen Gang wrote:
> 
> 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)

Why?  When *ppos >= size, it should return 0 (end of file) in my opinion.
ESPIPE means that any seek would be ineffective, not that a particular
seek went out of bounds.

Paul.
Chen Gang - May 21, 2013, 9:03 a.m.
On 05/21/2013 04:10 PM, Paul Mackerras wrote:
> On Tue, May 21, 2013 at 01:48:58PM +0800, Chen Gang wrote:
>> > 
>> > 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)
> Why?  When *ppos >= size, it should return 0 (end of file) in my opinion.
> ESPIPE means that any seek would be ineffective, not that a particular
> seek went out of bounds.

OK, thanks, I will send patch v2.  :-)


Thanks.

Patch

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);