On Tue, 12 Nov 2019 16:16:34 +0100, Arnd Bergmann wrote: > > This is a series I worked on with Baolin in 2017 and 2018, but we > never quite managed to finish up the last pieces. During the > ALSA developer meetup at ELC-E 2018 in Edinburgh, a decision was > made to go with this approach for keeping best compatibility > with existing source code, and then I failed to follow up by > resending the patches. > > Now I have patches for all remaining time_t uses in the kernel, > so it's absolutely time to revisit them. I have done more > review of the patches myself and found a couple of minor issues > that I have fixed up, otherwise the series is still the same as > before. > > Conceptually, the idea of these patches is: > > - 64-bit applications should see no changes at all, neither > compile-time nor run-time. > > - 32-bit code compiled with a 64-bit time_t currently > does not work with ALSA, and requires kernel changes and/or > sound/asound.h changes > > - Most 32-bit code using these interfaces will work correctly > on a modified kernel, with or without the uapi header changes. > > - 32-bit code using SNDRV_TIMER_IOCTL_TREAD requires the > updated header file for 64-bit time_t support > > - 32-bit i386 user space with 64-bit time_t is broken for > SNDRV_PCM_IOCTL_STATUS, SNDRV_RAWMIDI_IOCTL_STATUS and > SNDRV_PCM_IOCTL_SYNC_PTR because of i386 alignment. This is also > addressed by the updated uapi header. > > - PCM mmap is currently supported on native x86 kernels > (both 32-bit and 64-bit) but not for compat mode. This series breaks > the 32-bit native mmap support for 32-bit time_t, but instead allows > it for 64-bit time_t on both native and compat kernels. This seems to > be the best trade-off, as mmap support is optional already, and most > 32-bit code runs in compat mode anyway. > > - I've tried to avoid breaking compilation of 32-bit code > as much as possible. Anything that does break however is likely code > that is already broken on 64-bit time_t and needs source changes to > fix them. > > I would like to propose merging this into the alsa tree after > the v5.5 merge window for inclusion into v5.6, to allow a good > amount of testing, in particular for the header changes that > may cause problems for user space applications. Agreed, it's still no urgent problem. > A git branch with the same contents is available for testing at [1]. > > Please review and test! > > Arnd So now taking a quick look through the series, I find this approach is the way to go. Although one might get a bit more optimization after squeeze, it's already a good compromise between the readability and the efficiency. A slight uncertain implementation is the timer tread stuff, especially the conditional definition of SNDRV_TIMER_IOCTL_TREAD (IIRC, I already complained it in the past, too). But I have no other idea as well, so unless someone else gives a better option, we can live with that. Thanks! Takashi > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git y2038-alsa > [2] https://lore.kernel.org/lkml/CAK8P3a2Os66+iwQYf97qh05W2JP8rmWao8zmKoHiXqVHvyYAJA@xxxxxxxxxxxxxx/T/#m6519cb07cfda08adf1dedea6596bb98892b4d5dc > > Changes since v5 (Arnd): > - Rebased to linux-5.4-rc4 > - Updated to completely remove timespec and time_t references from alsa > - found and fixed a few bugs > > Changes since v4 (Baolin): > - Add patch 5 to change trigger_tstamp member of struct snd_pcm_runtime. > - Add patch 8 to change internal timespec. > - Add more explanation in commit message. > - Use ktime_get_real_ts64() in patch 6. > - Split common code out into a separate function in patch 6. > - Fix tu->tread bug in patch 6 and remove #if __BITS_PER_LONG == 64 macro. > > Changes since v3: > - Move struct snd_pcm_status32 to pcm.h file. > - Modify comments and commit message. > - Add new patch2 ~ patch6. > > Changes since v2: > - Renamed all structures to make clear. > - Remove CONFIG_X86_X32 macro and introduced new compat_snd_pcm_status64_x86_32. > > Changes since v1: > - Add one macro for struct snd_pcm_status_32 which only active in 32bits kernel. > - Convert pcm_compat.c to use struct snd_pcm_status_64. > - Convert pcm_native.c to use struct snd_pcm_status_64. > > --- > > Arnd Bergmann (2): > ALSA: move snd_pcm_ioctl_sync_ptr_compat into pcm_native.c > ALSA: add new 32-bit layout for snd_pcm_mmap_status/control > > Baolin Wang (6): > ALSA: Replace timespec with timespec64 > ALSA: Avoid using timespec for struct snd_timer_status > ALSA: Avoid using timespec for struct snd_ctl_elem_value > ALSA: Avoid using timespec for struct snd_pcm_status > ALSA: Avoid using timespec for struct snd_rawmidi_status > ALSA: Avoid using timespec for struct snd_timer_tread > > include/sound/pcm.h | 74 ++++++-- > include/sound/timer.h | 4 +- > include/uapi/sound/asound.h | 132 ++++++++++++-- > sound/core/pcm.c | 12 +- > sound/core/pcm_compat.c | 282 ++++++++---------------------- > sound/core/pcm_lib.c | 38 ++-- > sound/core/pcm_native.c | 226 +++++++++++++++++++++--- > sound/core/rawmidi.c | 132 +++++++++++--- > sound/core/rawmidi_compat.c | 87 +++------ > sound/core/timer.c | 229 ++++++++++++++++++------ > sound/core/timer_compat.c | 62 +------ > sound/pci/hda/hda_controller.c | 10 +- > sound/soc/intel/skylake/skl-pcm.c | 4 +- > 13 files changed, 804 insertions(+), 488 deletions(-) > > -- > 2.20.0 > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
