* [PATCH v3] xen/debugfs: Check debugfs initialization before using it
@ 2013-12-09 9:56 Ethan Zhao
2013-12-09 9:59 ` Ethan Zhao
2013-12-09 11:19 ` Greg KH
0 siblings, 2 replies; 5+ messages in thread
From: Ethan Zhao @ 2013-12-09 9:56 UTC (permalink / raw)
To: gregkh, konrad.wilk, raghavendra.kt; +Cc: linux-kernel, ethan.zhao
From: "ethan.zhao" <ethan.kernel@gmail.com>
Should check debugfs initialization with debugfs_initialized() before using it,
Because if it isn't initialized, the return value of fake debugfs_create_dir() etc
functions would be ERR_PTR(-ENODEV), checking with NULL will not work.
V3: add warning message when debugfs not configured or disabled.
Signed-off-by: ethan.zhao <ethan.kernel@gmail.com>
---
arch/x86/xen/debugfs.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
index c8377fb..85c0e0e 100644
--- a/arch/x86/xen/debugfs.c
+++ b/arch/x86/xen/debugfs.c
@@ -9,12 +9,18 @@ static struct dentry *d_xen_debug;
struct dentry * __init xen_init_debugfs(void)
{
+ if (!debugfs_initialized()) {
+ d_xen_debug = NULL;
+ goto nodebugfs;
+ }
+
if (!d_xen_debug) {
d_xen_debug = debugfs_create_dir("xen", NULL);
if (!d_xen_debug)
pr_warning("Could not create 'xen' debugfs directory\n");
}
+nodebugfs:
return d_xen_debug;
}
--
1.8.3.4 (Apple Git-47)
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH v3] xen/debugfs: Check debugfs initialization before using it
2013-12-09 9:56 [PATCH v3] xen/debugfs: Check debugfs initialization before using it Ethan Zhao
@ 2013-12-09 9:59 ` Ethan Zhao
2013-12-09 11:19 ` Greg KH
1 sibling, 0 replies; 5+ messages in thread
From: Ethan Zhao @ 2013-12-09 9:59 UTC (permalink / raw)
To: Greg KH, konrad.wilk, raghavendra.kt; +Cc: LKML, ethan.zhao
Greg,
How about the V3 ?
Thanks,
Ethan
On Mon, Dec 9, 2013 at 5:56 PM, Ethan Zhao <ethan.kernel@gmail.com> wrote:
> From: "ethan.zhao" <ethan.kernel@gmail.com>
>
> Should check debugfs initialization with debugfs_initialized() before using it,
> Because if it isn't initialized, the return value of fake debugfs_create_dir() etc
> functions would be ERR_PTR(-ENODEV), checking with NULL will not work.
>
> V3: add warning message when debugfs not configured or disabled.
>
> Signed-off-by: ethan.zhao <ethan.kernel@gmail.com>
> ---
> arch/x86/xen/debugfs.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
> index c8377fb..85c0e0e 100644
> --- a/arch/x86/xen/debugfs.c
> +++ b/arch/x86/xen/debugfs.c
> @@ -9,12 +9,18 @@ static struct dentry *d_xen_debug;
>
> struct dentry * __init xen_init_debugfs(void)
> {
> + if (!debugfs_initialized()) {
> + d_xen_debug = NULL;
> + goto nodebugfs;
> + }
> +
> if (!d_xen_debug) {
> d_xen_debug = debugfs_create_dir("xen", NULL);
>
> if (!d_xen_debug)
> pr_warning("Could not create 'xen' debugfs directory\n");
> }
> +nodebugfs:
>
> return d_xen_debug;
> }
> --
> 1.8.3.4 (Apple Git-47)
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] xen/debugfs: Check debugfs initialization before using it
2013-12-09 9:56 [PATCH v3] xen/debugfs: Check debugfs initialization before using it Ethan Zhao
2013-12-09 9:59 ` Ethan Zhao
@ 2013-12-09 11:19 ` Greg KH
2013-12-09 13:49 ` Ethan Zhao
1 sibling, 1 reply; 5+ messages in thread
From: Greg KH @ 2013-12-09 11:19 UTC (permalink / raw)
To: Ethan Zhao; +Cc: konrad.wilk, raghavendra.kt, linux-kernel
On Mon, Dec 09, 2013 at 05:56:52PM +0800, Ethan Zhao wrote:
> From: "ethan.zhao" <ethan.kernel@gmail.com>
>
> Should check debugfs initialization with debugfs_initialized() before using it,
> Because if it isn't initialized, the return value of fake debugfs_create_dir() etc
> functions would be ERR_PTR(-ENODEV), checking with NULL will not work.
>
> V3: add warning message when debugfs not configured or disabled.
That's not what this patch does...
> Signed-off-by: ethan.zhao <ethan.kernel@gmail.com>
> ---
> arch/x86/xen/debugfs.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
> index c8377fb..85c0e0e 100644
> --- a/arch/x86/xen/debugfs.c
> +++ b/arch/x86/xen/debugfs.c
> @@ -9,12 +9,18 @@ static struct dentry *d_xen_debug;
>
> struct dentry * __init xen_init_debugfs(void)
> {
> + if (!debugfs_initialized()) {
> + d_xen_debug = NULL;
> + goto nodebugfs;
> + }
Again, why is this even needed?
What problem in the existing code are you trying to solve?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] xen/debugfs: Check debugfs initialization before using it
2013-12-09 11:19 ` Greg KH
@ 2013-12-09 13:49 ` Ethan Zhao
2013-12-09 18:39 ` Greg KH
0 siblings, 1 reply; 5+ messages in thread
From: Ethan Zhao @ 2013-12-09 13:49 UTC (permalink / raw)
To: Greg KH; +Cc: konrad.wilk, raghavendra.kt, LKML
On Mon, Dec 9, 2013 at 7:19 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Mon, Dec 09, 2013 at 05:56:52PM +0800, Ethan Zhao wrote:
>> From: "ethan.zhao" <ethan.kernel@gmail.com>
>>
>> Should check debugfs initialization with debugfs_initialized() before using it,
>> Because if it isn't initialized, the return value of fake debugfs_create_dir() etc
>> functions would be ERR_PTR(-ENODEV), checking with NULL will not work.
>>
>> V3: add warning message when debugfs not configured or disabled.
>
> That's not what this patch does...
>
>> Signed-off-by: ethan.zhao <ethan.kernel@gmail.com>
>> ---
>> arch/x86/xen/debugfs.c | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
>> index c8377fb..85c0e0e 100644
>> --- a/arch/x86/xen/debugfs.c
>> +++ b/arch/x86/xen/debugfs.c
>> @@ -9,12 +9,18 @@ static struct dentry *d_xen_debug;
>>
>> struct dentry * __init xen_init_debugfs(void)
>> {
>> + if (!debugfs_initialized()) {
>> + d_xen_debug = NULL;
>> + goto nodebugfs;
>> + }
>
> Again, why is this even needed?
>
> What problem in the existing code are you trying to solve?
>
What I want to ask who is so smart and fake some many functions when
CONFIG_DEBUG_FS is not configured/defined and the build could pass
without any error ? What is the motive make him wrote some many fake
function and why he wrote the debugfs_initialized() function seem
'useless' at all ?
Thanks,
Ethan
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3] xen/debugfs: Check debugfs initialization before using it
2013-12-09 13:49 ` Ethan Zhao
@ 2013-12-09 18:39 ` Greg KH
0 siblings, 0 replies; 5+ messages in thread
From: Greg KH @ 2013-12-09 18:39 UTC (permalink / raw)
To: Ethan Zhao; +Cc: konrad.wilk, raghavendra.kt, LKML
On Mon, Dec 09, 2013 at 09:49:36PM +0800, Ethan Zhao wrote:
> On Mon, Dec 9, 2013 at 7:19 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Mon, Dec 09, 2013 at 05:56:52PM +0800, Ethan Zhao wrote:
> >> From: "ethan.zhao" <ethan.kernel@gmail.com>
> >>
> >> Should check debugfs initialization with debugfs_initialized() before using it,
> >> Because if it isn't initialized, the return value of fake debugfs_create_dir() etc
> >> functions would be ERR_PTR(-ENODEV), checking with NULL will not work.
> >>
> >> V3: add warning message when debugfs not configured or disabled.
> >
> > That's not what this patch does...
> >
> >> Signed-off-by: ethan.zhao <ethan.kernel@gmail.com>
> >> ---
> >> arch/x86/xen/debugfs.c | 6 ++++++
> >> 1 file changed, 6 insertions(+)
> >>
> >> diff --git a/arch/x86/xen/debugfs.c b/arch/x86/xen/debugfs.c
> >> index c8377fb..85c0e0e 100644
> >> --- a/arch/x86/xen/debugfs.c
> >> +++ b/arch/x86/xen/debugfs.c
> >> @@ -9,12 +9,18 @@ static struct dentry *d_xen_debug;
> >>
> >> struct dentry * __init xen_init_debugfs(void)
> >> {
> >> + if (!debugfs_initialized()) {
> >> + d_xen_debug = NULL;
> >> + goto nodebugfs;
> >> + }
> >
> > Again, why is this even needed?
> >
> > What problem in the existing code are you trying to solve?
> >
> What I want to ask who is so smart and fake some many functions when
> CONFIG_DEBUG_FS is not configured/defined and the build could pass
> without any error ?
That's the way this has always worked.
> What is the motive make him wrote some many fake function and why he
> wrote the debugfs_initialized() function seem 'useless' at all ?
To make the caller code easier, and smaller, and to not care if debugfs
is enabled in the kernel build or not at all.
Ok, I answered your questions, now care to answer mine?
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2013-12-09 18:38 UTC | newest]
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2013-12-09 9:56 [PATCH v3] xen/debugfs: Check debugfs initialization before using it Ethan Zhao
2013-12-09 9:59 ` Ethan Zhao
2013-12-09 11:19 ` Greg KH
2013-12-09 13:49 ` Ethan Zhao
2013-12-09 18:39 ` Greg KH
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