From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Verkuil Subject: Re: sparse: ARRAY_SIZE and sparse array initialization Date: Fri, 28 Mar 2014 11:50:14 +0100 Message-ID: <533553E6.3060508@xs4all.nl> References: <532442E2.7050206@xs4all.nl> <532443AB.9080105@xs4all.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp-vbr2.xs4all.nl ([194.109.24.22]:2199 "EHLO smtp-vbr2.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751721AbaC1KuU (ORCPT ); Fri, 28 Mar 2014 06:50:20 -0400 In-Reply-To: <532443AB.9080105@xs4all.nl> Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: linux-sparse@vger.kernel.org Cc: Linux Media Mailing List Is there any chance that the three issues I reported will be fixed? If not, then I'll work around it in the kernel code. Regards, Hans On 03/15/2014 01:12 PM, Hans Verkuil wrote: > For the record: all these tests were done with a 3.14-rc5 kernel and sparse > compiled from the git tree as of today (version v0.5.0). The gcc version is 4.8.2. > > Regards, > > Hans > > On 03/15/2014 01:09 PM, Hans Verkuil wrote: >> Hmm, interesting. Twice 'sparse' in the same subject line with different meanings :-) >> >> This is another sparse error I get with drivers/media/v4l2-core/v4l2-ioctl.c: >> >> drivers/media/v4l2-core/v4l2-ioctl.c:424:9: error: cannot size expression >> >> (there are more of those in drivers/media, all with the same cause). >> >> This sparse (the tool) error occurs because of sparse (C language) array initialization >> in combination with ARRAY_SIZE: >> >> static const char *v4l2_memory_names[] = { >> [V4L2_MEMORY_MMAP] = "mmap", >> [V4L2_MEMORY_USERPTR] = "userptr", >> [V4L2_MEMORY_OVERLAY] = "overlay", >> [V4L2_MEMORY_DMABUF] = "dmabuf", >> }; >> >> #define prt_names(a, arr) (((unsigned)(a)) < ARRAY_SIZE(arr) ? arr[a] : "unknown") >> >> static void v4l_print_requestbuffers(const void *arg, bool write_only) >> { >> const struct v4l2_requestbuffers *p = arg; >> >> pr_cont("count=%d, type=%s, memory=%s\n", >> p->count, >> prt_names(p->type, v4l2_type_names), >> prt_names(p->memory, v4l2_memory_names)); >> } >> >> I could change v4l2_memory_names to: >> >> static const char *v4l2_memory_names[V4L2_MEMORY_DMABUF + 1] = { >> >> and the error goes away. >> >> I'm actually not sure if this is a sparse bug or a feature. >> >> If it is a feature then the error message is definitely wrong, since the size is >> perfectly well defined. As an aside: the error message is pretty vague IMHO. >> >> Regards, >> >> Hans >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-media" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sparse" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >