2015-12-09 17:08:19

by Niranjan Dighe

[permalink] [raw]
Subject: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse

The third argument to function kportal_memhog_alloc is expected to
be gfp_t whereas the actual argument was unsigned int. Fix this by
explicitly typecasting to gfp_t

Signed-off-by: Niranjan Dighe <[email protected]>
---
drivers/staging/lustre/lustre/libcfs/module.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/lustre/lustre/libcfs/module.c b/drivers/staging/lustre/lustre/libcfs/module.c
index 96d9d46..9c79f6e 100644
--- a/drivers/staging/lustre/lustre/libcfs/module.c
+++ b/drivers/staging/lustre/lustre/libcfs/module.c
@@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file *pfile, unsigned long cmd,
/* XXX The ioc_flags is not GFP flags now, need to be fixed */
err = kportal_memhog_alloc(pfile->private_data,
data->ioc_count,
- data->ioc_flags);
+ (__force gfp_t)data->ioc_flags);
if (err != 0)
kportal_memhog_free(pfile->private_data);
}
--
1.9.1


2015-12-21 23:45:00

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse

On Wed, Dec 09, 2015 at 10:38:13PM +0530, Niranjan Dighe wrote:
> The third argument to function kportal_memhog_alloc is expected to
> be gfp_t whereas the actual argument was unsigned int. Fix this by
> explicitly typecasting to gfp_t
>
> Signed-off-by: Niranjan Dighe <[email protected]>
> ---
> drivers/staging/lustre/lustre/libcfs/module.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/lustre/lustre/libcfs/module.c b/drivers/staging/lustre/lustre/libcfs/module.c
> index 96d9d46..9c79f6e 100644
> --- a/drivers/staging/lustre/lustre/libcfs/module.c
> +++ b/drivers/staging/lustre/lustre/libcfs/module.c
> @@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file *pfile, unsigned long cmd,
> /* XXX The ioc_flags is not GFP flags now, need to be fixed */
> err = kportal_memhog_alloc(pfile->private_data,
> data->ioc_count,
> - data->ioc_flags);
> + (__force gfp_t)data->ioc_flags);

No, please fix the type to be correct properly, like the comment says
needs to be done.

thanks,

greg k-h

2015-12-22 13:05:24

by Niranjan Dighe

[permalink] [raw]
Subject: Re: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse

On Tue, Dec 22, 2015 at 5:14 AM, Greg Kroah-Hartman
<[email protected]> wrote:
> On Wed, Dec 09, 2015 at 10:38:13PM +0530, Niranjan Dighe wrote:
>> The third argument to function kportal_memhog_alloc is expected to
>> be gfp_t whereas the actual argument was unsigned int. Fix this by
>> explicitly typecasting to gfp_t
>>
>> Signed-off-by: Niranjan Dighe <[email protected]>
>> ---
>> drivers/staging/lustre/lustre/libcfs/module.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/staging/lustre/lustre/libcfs/module.c b/drivers/staging/lustre/lustre/libcfs/module.c
>> index 96d9d46..9c79f6e 100644
>> --- a/drivers/staging/lustre/lustre/libcfs/module.c
>> +++ b/drivers/staging/lustre/lustre/libcfs/module.c
>> @@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file *pfile, unsigned long cmd,
>> /* XXX The ioc_flags is not GFP flags now, need to be fixed */
>> err = kportal_memhog_alloc(pfile->private_data,
>> data->ioc_count,
>> - data->ioc_flags);
>> + (__force gfp_t)data->ioc_flags);
>
> No, please fix the type to be correct properly, like the comment says
> needs to be done.
>
> thanks,
>
> greg k-h

Hello Greg,

I could see that the ioc_flags member of the struct libcfs_ioctl_data
is used as gfp_t only in the
case of the ioctl IOC_LIBCFS_MEMHOG. I can think of following ways to
correct it -

1. Create a union that has 2 different types encapsulated, something like this -
union {
__u32 ioc_flags;
gfp_t alloc_flags;
}flags;
Because, the ioc_flags seems to be used in different contexts at
different places throughout the
drivers/staging/lustre directory.

2. Is it OK to hardcode the appropriate gfp_t flags for the
IOC_LIBCFS_MEMHOG, as the userspace
seems to be taking the decision about the page allocation
zone/strategy, is this what is intended?


Regards,
Niranjan Dighe

2015-12-22 15:26:33

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse

On Tue, Dec 22, 2015 at 06:35:21PM +0530, Niranjan Dighe wrote:
> On Tue, Dec 22, 2015 at 5:14 AM, Greg Kroah-Hartman
> <[email protected]> wrote:
> > On Wed, Dec 09, 2015 at 10:38:13PM +0530, Niranjan Dighe wrote:
> >> The third argument to function kportal_memhog_alloc is expected to
> >> be gfp_t whereas the actual argument was unsigned int. Fix this by
> >> explicitly typecasting to gfp_t
> >>
> >> Signed-off-by: Niranjan Dighe <[email protected]>
> >> ---
> >> drivers/staging/lustre/lustre/libcfs/module.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/staging/lustre/lustre/libcfs/module.c b/drivers/staging/lustre/lustre/libcfs/module.c
> >> index 96d9d46..9c79f6e 100644
> >> --- a/drivers/staging/lustre/lustre/libcfs/module.c
> >> +++ b/drivers/staging/lustre/lustre/libcfs/module.c
> >> @@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file *pfile, unsigned long cmd,
> >> /* XXX The ioc_flags is not GFP flags now, need to be fixed */
> >> err = kportal_memhog_alloc(pfile->private_data,
> >> data->ioc_count,
> >> - data->ioc_flags);
> >> + (__force gfp_t)data->ioc_flags);
> >
> > No, please fix the type to be correct properly, like the comment says
> > needs to be done.
> >
> > thanks,
> >
> > greg k-h
>
> Hello Greg,
>
> I could see that the ioc_flags member of the struct libcfs_ioctl_data
> is used as gfp_t only in the
> case of the ioctl IOC_LIBCFS_MEMHOG. I can think of following ways to
> correct it -
>
> 1. Create a union that has 2 different types encapsulated, something like this -
> union {
> __u32 ioc_flags;
> gfp_t alloc_flags;
> }flags;
> Because, the ioc_flags seems to be used in different contexts at
> different places throughout the
> drivers/staging/lustre directory.

This crosses the user/kernel boundry? Hah, no, just drop it, don't
touch this at all, lustre ioctls are a complete mess and need to be
fixed up by the authors who can test them, just leave this alone for
now, sorry.

greg k-h

2015-12-22 22:04:08

by Dilger, Andreas

[permalink] [raw]
Subject: Re: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse

On 2015/12/22, 06:05, "Niranjan Dighe" <[email protected]> wrote:

>On Tue, Dec 22, 2015 at 5:14 AM, Greg Kroah-Hartman
><[email protected]> wrote:
>> On Wed, Dec 09, 2015 at 10:38:13PM +0530, Niranjan Dighe wrote:
>>> The third argument to function kportal_memhog_alloc is expected to
>>> be gfp_t whereas the actual argument was unsigned int. Fix this by
>>> explicitly typecasting to gfp_t
>>>
>>> Signed-off-by: Niranjan Dighe <[email protected]>
>>> ---
>>> drivers/staging/lustre/lustre/libcfs/module.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/staging/lustre/lustre/libcfs/module.c
>>>b/drivers/staging/lustre/lustre/libcfs/module.c
>>> index 96d9d46..9c79f6e 100644
>>> --- a/drivers/staging/lustre/lustre/libcfs/module.c
>>> +++ b/drivers/staging/lustre/lustre/libcfs/module.c
>>> @@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file
>>>*pfile, unsigned long cmd,
>>> /* XXX The ioc_flags is not GFP flags now, need
>>>to be fixed */
>>> err = kportal_memhog_alloc(pfile->private_data,
>>> data->ioc_count,
>>> - data->ioc_flags);
>>> + (__force gfp_t)data->ioc_flags);
>>
>> No, please fix the type to be correct properly, like the comment says
>> needs to be done.
>>
>> thanks,
>>
>> greg k-h
>
>Hello Greg,
>
>I could see that the ioc_flags member of the struct libcfs_ioctl_data
>is used as gfp_t only in the
>case of the ioctl IOC_LIBCFS_MEMHOG. I can think of following ways to
>correct it -
>
>1. Create a union that has 2 different types encapsulated, something like
>this -
> union {
> __u32 ioc_flags;
> gfp_t alloc_flags;
> }flags;
>Because, the ioc_flags seems to be used in different contexts at
>different places throughout the
>drivers/staging/lustre directory.
>
>2. Is it OK to hardcode the appropriate gfp_t flags for the
>IOC_LIBCFS_MEMHOG, as the userspace
>seems to be taking the decision about the page allocation
>zone/strategy, is this what is intended?

The memhog functionality is used to introduce memory pressure on a client
or server during operation to test error handling as well as memory
allocation deadlocks (e.g. GFP_KERNEL used where GFP_NOFS should be used).
There are other ways to do this in the kernel today, so all of the memhog
code could just be deleted I think.

This looks like kportal_memhog_alloc(), kportal_memhog_free(),
IOC_LIBCFS_MEMHOG, and struct libcfs_device_userstate could be removed.


Cheers, Andreas

2015-12-23 06:27:53

by Niranjan Dighe

[permalink] [raw]
Subject: Re: [PATCH] staging: lustre/lustre/libcfs: Fix type mismatch reported by sparse

On Wed, Dec 23, 2015 at 3:34 AM, Dilger, Andreas
<[email protected]> wrote:
> On 2015/12/22, 06:05, "Niranjan Dighe" <[email protected]> wrote:
>
>>On Tue, Dec 22, 2015 at 5:14 AM, Greg Kroah-Hartman
>><[email protected]> wrote:
>>> On Wed, Dec 09, 2015 at 10:38:13PM +0530, Niranjan Dighe wrote:
>>>> The third argument to function kportal_memhog_alloc is expected to
>>>> be gfp_t whereas the actual argument was unsigned int. Fix this by
>>>> explicitly typecasting to gfp_t
>>>>
>>>> Signed-off-by: Niranjan Dighe <[email protected]>
>>>> ---
>>>> drivers/staging/lustre/lustre/libcfs/module.c | 2 +-
>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/staging/lustre/lustre/libcfs/module.c
>>>>b/drivers/staging/lustre/lustre/libcfs/module.c
>>>> index 96d9d46..9c79f6e 100644
>>>> --- a/drivers/staging/lustre/lustre/libcfs/module.c
>>>> +++ b/drivers/staging/lustre/lustre/libcfs/module.c
>>>> @@ -268,7 +268,7 @@ static int libcfs_ioctl_int(struct cfs_psdev_file
>>>>*pfile, unsigned long cmd,
>>>> /* XXX The ioc_flags is not GFP flags now, need
>>>>to be fixed */
>>>> err = kportal_memhog_alloc(pfile->private_data,
>>>> data->ioc_count,
>>>> - data->ioc_flags);
>>>> + (__force gfp_t)data->ioc_flags);
>>>
>>> No, please fix the type to be correct properly, like the comment says
>>> needs to be done.
>>>
>>> thanks,
>>>
>>> greg k-h
>>
>>Hello Greg,
>>
>>I could see that the ioc_flags member of the struct libcfs_ioctl_data
>>is used as gfp_t only in the
>>case of the ioctl IOC_LIBCFS_MEMHOG. I can think of following ways to
>>correct it -
>>
>>1. Create a union that has 2 different types encapsulated, something like
>>this -
>> union {
>> __u32 ioc_flags;
>> gfp_t alloc_flags;
>> }flags;
>>Because, the ioc_flags seems to be used in different contexts at
>>different places throughout the
>>drivers/staging/lustre directory.
>>
>>2. Is it OK to hardcode the appropriate gfp_t flags for the
>>IOC_LIBCFS_MEMHOG, as the userspace
>>seems to be taking the decision about the page allocation
>>zone/strategy, is this what is intended?
>
> The memhog functionality is used to introduce memory pressure on a client
> or server during operation to test error handling as well as memory
> allocation deadlocks (e.g. GFP_KERNEL used where GFP_NOFS should be used).
> There are other ways to do this in the kernel today, so all of the memhog
> code could just be deleted I think.
>
> This looks like kportal_memhog_alloc(), kportal_memhog_free(),
> IOC_LIBCFS_MEMHOG, and struct libcfs_device_userstate could be removed.
>
>
> Cheers, Andreas
>

Thanks Andreas, I will send out a separate patch with the cleanup as
you suggested.

Regards,
Niranjan