-----Original Message----- From: Takashi Iwai [mailto:tiwai@xxxxxxx] Sent: Thursday, August 28, 2008 8:45 PM To: Bryan Wu Cc: perex@xxxxxxxx; liam.girdwood@xxxxxxxxxxxxxxxx; broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Cliff Cai Subject: Re: [PATCH 4/4] ALSA: add dummy function to support shared mmap in nommu Blackfin arch At Wed, 27 Aug 2008 17:39:28 +0800, Bryan Wu wrote: > > From: Cliff Cai <cliff.cai@xxxxxxxxxx> > > Signed-off-by: Cliff Cai <cliff.cai@xxxxxxxxxx> > Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx> > --- > sound/core/pcm_native.c | 8 ++++++++ > 1 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c index > c49b9d9..cb202a1 100644 > --- a/sound/core/pcm_native.c > +++ b/sound/core/pcm_native.c > @@ -3391,6 +3391,12 @@ out: > } > #endif /* CONFIG_SND_SUPPORT_OLD_API */ > > +unsigned long dummy_get_unmapped_area(struct file *file, unsigned long addr, > + unsigned long len, unsigned long pgoff, unsigned long > +flags) { > + return 0; > +} >Always zero is confirmed to work for other architectures, too? I'm not sure about this but for non-mmu arch it's enough and harmless. > /* > * Register section > */ > @@ -3407,6 +3413,7 @@ const struct file_operations snd_pcm_f_ops[2] = { > .compat_ioctl = snd_pcm_ioctl_compat, > .mmap = snd_pcm_mmap, > .fasync = snd_pcm_fasync, > + .get_unmapped_area = dummy_get_unmapped_area, > }, > { > .owner = THIS_MODULE, > @@ -3419,5 +3426,6 @@ const struct file_operations snd_pcm_f_ops[2] = { > .compat_ioctl = snd_pcm_ioctl_compat, > .mmap = snd_pcm_mmap, > .fasync = snd_pcm_fasync, > + .get_unmapped_area = dummy_get_unmapped_area, > } > }; >I don't think adding this dummy get_unmapped_area unconditionally for every driver is good. This overrides the default >mm->get_unmaped_area. But without this dummy function,shared mmap on nommu arch would fail,refer to validate_mmap_request() in mm/nommu.c. May be we can add a kernel config item to include or not include this function depending on non-mmu or mmu arch. Cliff _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
