* [PATCH 2/4] uml: helper.c warning corrections
@ 2011-07-04 23:15 Vitaliy Ivanov
2011-07-05 9:42 ` Richard Weinberger
0 siblings, 1 reply; 5+ messages in thread
From: Vitaliy Ivanov @ 2011-07-04 23:15 UTC (permalink / raw)
To: Jeff Dike, Richard Weinberger, Linus Torvalds, akpm
Cc: user-mode-linux-devel, lkml
>From 7296c5b9770e95cd6ad4e9e71d2d14c972abdfe1 Mon Sep 17 00:00:00 2001
From: Vitaliy Ivanov <vitalivanov@gmail.com>
Date: Tue, 5 Jul 2011 02:03:06 +0300
Subject: [PATCH 2/4] uml: helper.c warning corrections
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
arch/um/os-Linux/helper.c: In function ‘helper_child’:
arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result
Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
---
arch/um/os-Linux/helper.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index b6b1096..feff22d 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -28,14 +28,14 @@ static int helper_child(void *arg)
{
struct helper_data *data = arg;
char **argv = data->argv;
- int err;
+ int err, ret;
if (data->pre_exec != NULL)
(*data->pre_exec)(data->pre_data);
err = execvp_noalloc(data->buf, argv[0], argv);
/* If the exec succeeds, we don't get here */
- write(data->fd, &err, sizeof(err));
+ CATCH_EINTR(ret = write(data->fd, &err, sizeof(err)));
return 0;
}
--
1.7.4.1
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 2/4] uml: helper.c warning corrections
2011-07-04 23:15 [PATCH 2/4] uml: helper.c warning corrections Vitaliy Ivanov
@ 2011-07-05 9:42 ` Richard Weinberger
2011-07-05 11:45 ` Vitaliy Ivanov
0 siblings, 1 reply; 5+ messages in thread
From: Richard Weinberger @ 2011-07-05 9:42 UTC (permalink / raw)
To: vitalivanov; +Cc: Jeff Dike, Linus Torvalds, akpm, user-mode-linux-devel, lkml
Am Dienstag 05 Juli 2011, 01:15:47 schrieb Vitaliy Ivanov:
> From 7296c5b9770e95cd6ad4e9e71d2d14c972abdfe1 Mon Sep 17 00:00:00 2001
> From: Vitaliy Ivanov <vitalivanov@gmail.com>
> Date: Tue, 5 Jul 2011 02:03:06 +0300
> Subject: [PATCH 2/4] uml: helper.c warning corrections
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> arch/um/os-Linux/helper.c: In function ‘helper_child’:
> arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of ‘write’,
> declared with attribute warn_unused_result
Same question as before...
> Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
> ---
> arch/um/os-Linux/helper.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
> index b6b1096..feff22d 100644
> --- a/arch/um/os-Linux/helper.c
> +++ b/arch/um/os-Linux/helper.c
> @@ -28,14 +28,14 @@ static int helper_child(void *arg)
> {
> struct helper_data *data = arg;
> char **argv = data->argv;
> - int err;
> + int err, ret;
>
> if (data->pre_exec != NULL)
> (*data->pre_exec)(data->pre_data);
> err = execvp_noalloc(data->buf, argv[0], argv);
>
> /* If the exec succeeds, we don't get here */
> - write(data->fd, &err, sizeof(err));
> + CATCH_EINTR(ret = write(data->fd, &err, sizeof(err)));
Is there really a realistic chance that this write() can be interrupted?
helper_child() gets called via clone() in run_helper().
Thanks,
//richard
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 2/4] uml: helper.c warning corrections
2011-07-05 9:42 ` Richard Weinberger
@ 2011-07-05 11:45 ` Vitaliy Ivanov
2011-07-05 12:02 ` Richard Weinberger
0 siblings, 1 reply; 5+ messages in thread
From: Vitaliy Ivanov @ 2011-07-05 11:45 UTC (permalink / raw)
To: Richard Weinberger
Cc: Jeff Dike, Linus Torvalds, akpm, user-mode-linux-devel, lkml
Richard,
On Tue, Jul 5, 2011 at 12:42 PM, Richard Weinberger <richard@nod.at> wrote:
> Am Dienstag 05 Juli 2011, 01:15:47 schrieb Vitaliy Ivanov:
>> From 7296c5b9770e95cd6ad4e9e71d2d14c972abdfe1 Mon Sep 17 00:00:00 2001
>> From: Vitaliy Ivanov <vitalivanov@gmail.com>
>> Date: Tue, 5 Jul 2011 02:03:06 +0300
>> Subject: [PATCH 2/4] uml: helper.c warning corrections
>> MIME-Version: 1.0
>> Content-Type: text/plain; charset=UTF-8
>> Content-Transfer-Encoding: 8bit
>>
>> arch/um/os-Linux/helper.c: In function ‘helper_child’:
>> arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of ‘write’,
>> declared with attribute warn_unused_result
>
> Same question as before...
Same answer is here:)
>> Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
>> ---
>> arch/um/os-Linux/helper.c | 4 ++--
>> 1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
>> index b6b1096..feff22d 100644
>> --- a/arch/um/os-Linux/helper.c
>> +++ b/arch/um/os-Linux/helper.c
>> @@ -28,14 +28,14 @@ static int helper_child(void *arg)
>> {
>> struct helper_data *data = arg;
>> char **argv = data->argv;
>> - int err;
>> + int err, ret;
>>
>> if (data->pre_exec != NULL)
>> (*data->pre_exec)(data->pre_data);
>> err = execvp_noalloc(data->buf, argv[0], argv);
>>
>> /* If the exec succeeds, we don't get here */
>> - write(data->fd, &err, sizeof(err));
>> + CATCH_EINTR(ret = write(data->fd, &err, sizeof(err)));
>
> Is there really a realistic chance that this write() can be interrupted?
> helper_child() gets called via clone() in run_helper().
It's always better not to think whether it's possible but simply kill
all the chances for this to happen.
In this case that's pretty trivial thing and also it solves issue with warning.
Vitaliy
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 2/4] uml: helper.c warning corrections
2011-07-05 11:45 ` Vitaliy Ivanov
@ 2011-07-05 12:02 ` Richard Weinberger
2011-07-05 12:28 ` Vitaliy Ivanov
0 siblings, 1 reply; 5+ messages in thread
From: Richard Weinberger @ 2011-07-05 12:02 UTC (permalink / raw)
To: Vitaliy Ivanov
Cc: Jeff Dike, Linus Torvalds, akpm, user-mode-linux-devel, lkml
Am Dienstag 05 Juli 2011, 13:45:06 schrieb Vitaliy Ivanov:
> Richard,
>
> On Tue, Jul 5, 2011 at 12:42 PM, Richard Weinberger <richard@nod.at> wrote:
> > Am Dienstag 05 Juli 2011, 01:15:47 schrieb Vitaliy Ivanov:
> >> From 7296c5b9770e95cd6ad4e9e71d2d14c972abdfe1 Mon Sep 17 00:00:00 2001
> >> From: Vitaliy Ivanov <vitalivanov@gmail.com>
> >> Date: Tue, 5 Jul 2011 02:03:06 +0300
> >> Subject: [PATCH 2/4] uml: helper.c warning corrections
> >> MIME-Version: 1.0
> >> Content-Type: text/plain; charset=UTF-8
> >> Content-Transfer-Encoding: 8bit
> >>
> >> arch/um/os-Linux/helper.c: In function ‘helper_child’:
> >> arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of
> >> ‘write’, declared with attribute warn_unused_result
> >
> > Same question as before...
>
> Same answer is here:)
>
> >> Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com>
> >> ---
> >> arch/um/os-Linux/helper.c | 4 ++--
> >> 1 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
> >> index b6b1096..feff22d 100644
> >> --- a/arch/um/os-Linux/helper.c
> >> +++ b/arch/um/os-Linux/helper.c
> >> @@ -28,14 +28,14 @@ static int helper_child(void *arg)
> >> {
> >> struct helper_data *data = arg;
> >> char **argv = data->argv;
> >> - int err;
> >> + int err, ret;
> >>
> >> if (data->pre_exec != NULL)
> >> (*data->pre_exec)(data->pre_data);
> >> err = execvp_noalloc(data->buf, argv[0], argv);
> >>
> >> /* If the exec succeeds, we don't get here */
> >> - write(data->fd, &err, sizeof(err));
> >> + CATCH_EINTR(ret = write(data->fd, &err, sizeof(err)));
> >
> > Is there really a realistic chance that this write() can be interrupted?
> > helper_child() gets called via clone() in run_helper().
>
> It's always better not to think whether it's possible but simply kill
> all the chances for this to happen.
> In this case that's pretty trivial thing and also it solves issue with
> warning.
Defensive programming is not a solution for everything.
CPU time and memory are not for free, especially in kernel land.
Anyway, when this patch removes a real warning, it's fine for me.
Applied.
Thanks,
//richard
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 2/4] uml: helper.c warning corrections
2011-07-05 12:02 ` Richard Weinberger
@ 2011-07-05 12:28 ` Vitaliy Ivanov
0 siblings, 0 replies; 5+ messages in thread
From: Vitaliy Ivanov @ 2011-07-05 12:28 UTC (permalink / raw)
To: Richard Weinberger
Cc: Jeff Dike, Linus Torvalds, akpm, user-mode-linux-devel, lkml
On Tue, Jul 5, 2011 at 3:02 PM, Richard Weinberger <richard@nod.at> wrote:
> Am Dienstag 05 Juli 2011, 13:45:06 schrieb Vitaliy Ivanov:
>> It's always better not to think whether it's possible but simply kill
>> all the chances for this to happen.
>> In this case that's pretty trivial thing and also it solves issue with
>> warning.
>
> Defensive programming is not a solution for everything.
> CPU time and memory are not for free, especially in kernel land.
>
> Anyway, when this patch removes a real warning, it's fine for me.
> Applied.
Thanks Richard.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2011-07-04 23:15 [PATCH 2/4] uml: helper.c warning corrections Vitaliy Ivanov
2011-07-05 9:42 ` Richard Weinberger
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2011-07-05 12:02 ` Richard Weinberger
2011-07-05 12:28 ` Vitaliy Ivanov
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