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

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

[Chen Gang]

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

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

[Paul Mackerras]

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.

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

[Chen Gang]

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.
-- 
Chen Gang

Asianux Corporation

[PATCH v2] PowerPC: kernel: need return the related error code when failure occurs

[Chen Gang]

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').

Also set ret value when only need it, so can save structions for normal
cases.

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 |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
index 48fbc2b..8213ee1 100644
--- a/arch/powerpc/kernel/nvram_64.c
+++ b/arch/powerpc/kernel/nvram_64.c
@@ -84,22 +84,30 @@ static ssize_t dev_nvram_read(struct file *file, char __user *buf,
 	char *tmp = NULL;
 	ssize_t size;
 
-	ret = -ENODEV;
-	if (!ppc_md.nvram_size)
+	if (!ppc_md.nvram_size) {
+		ret = -ENODEV;
 		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 = 0;
 		goto out;
+	}
 
 	count = min_t(size_t, count, size - *ppos);
 	count = min(count, PAGE_SIZE);
 
-	ret = -ENOMEM;
 	tmp = kmalloc(count, GFP_KERNEL);
-	if (!tmp)
+	if (!tmp) {
+		ret = -ENOMEM;
 		goto out;
+	}
 
 	ret = ppc_md.nvram_read(tmp, count, ppos);
 	if (ret <= 0)
-- 
1.7.7.6

Re: [PATCH v2] PowerPC: kernel: need return the related error code when failure occurs

[Chen Gang]

Hello Maintainers:

Please help check this patch whether is OK, when you have time.

Thanks.

On 05/21/2013 05:20 PM, 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').
> 
> Also set ret value when only need it, so can save structions for normal
> cases.
> 
> 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 |   20 ++++++++++++++------
>  1 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
> index 48fbc2b..8213ee1 100644
> --- a/arch/powerpc/kernel/nvram_64.c
> +++ b/arch/powerpc/kernel/nvram_64.c
> @@ -84,22 +84,30 @@ static ssize_t dev_nvram_read(struct file *file, char __user *buf,
>  	char *tmp = NULL;
>  	ssize_t size;
>  
> -	ret = -ENODEV;
> -	if (!ppc_md.nvram_size)
> +	if (!ppc_md.nvram_size) {
> +		ret = -ENODEV;
>  		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 = 0;
>  		goto out;
> +	}
>  
>  	count = min_t(size_t, count, size - *ppos);
>  	count = min(count, PAGE_SIZE);
>  
> -	ret = -ENOMEM;
>  	tmp = kmalloc(count, GFP_KERNEL);
> -	if (!tmp)
> +	if (!tmp) {
> +		ret = -ENOMEM;
>  		goto out;
> +	}
>  
>  	ret = ppc_md.nvram_read(tmp, count, ppos);
>  	if (ret <= 0)
> 


-- 
Chen Gang

Asianux Corporation