linux-kernel - Re: [PATCH 11/14] staging: android: ion: Allow heap name to be null

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Message-ID: <20190116152807.phyq5pqrmbkj6oxk@DESKTOP-E1NTVVP.localdomain>
Date:   Wed, 16 Jan 2019 15:28:10 +0000
From:   Brian Starkey <Brian.Starkey@....com>
To:     "Andrew F. Davis" <afd@...com>
CC:     Laura Abbott <labbott@...hat.com>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arve Hjønnevåg <arve@...roid.com>,
        "devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        nd <nd@....com>
Subject: Re: [PATCH 11/14] staging: android: ion: Allow heap name to be null

Hi Andrew,

On Fri, Jan 11, 2019 at 12:05:20PM -0600, Andrew F. Davis wrote:
> The heap name can be used for debugging but otherwise does not seem
> to be required and no other part of the code will fail if left NULL
> except here. We can make it required and check for it at some point,
> for now lets just prevent this from causing a NULL pointer exception.

I'm not so keen on this one. In the "new" API with heap querying, the
name string is the only way to identify the heap. I think Laura
mentioned at XDC2017 that it was expected that userspace should use
the strings to find the heap they want.

I'd actually be in favor of making the string a more strict UAPI than
allowing it to be empty (at least, if heap name strings is the API we
decide on for identifying heaps - which is another discussion).

Cheers,
-Brian

> 
> Signed-off-by: Andrew F. Davis <afd@...com>
> ---
>  drivers/staging/android/ion/ion.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index bba5f682bc25..14e48f6eb734 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -467,7 +467,7 @@ static int ion_query_heaps(struct ion_heap_query *query)
>  	max_cnt = query->cnt;
>  
>  	plist_for_each_entry(heap, &dev->heaps, node) {
> -		strncpy(hdata.name, heap->name, MAX_HEAP_NAME);
> +		strncpy(hdata.name, heap->name ?: "(null)", MAX_HEAP_NAME);
>  		hdata.name[sizeof(hdata.name) - 1] = '\0';
>  		hdata.type = heap->type;
>  		hdata.heap_id = heap->id;
> -- 
> 2.19.1
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

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