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    Merge tag 'y2038-alsa-v8-signed' of... · df1d6ea0
    Takashi Iwai authored
    Merge tag 'y2038-alsa-v8-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground into for-next
    
    ALSA: Fix year 2038 issue for sound subsystem
    
    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.
    
    [1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git y2038-alsa-v8
    [2] https://lore.kernel.org/lkml/CAK8P3a2Os66+iwQYf97qh05W2JP8rmWao8zmKoHiXqVHvyYAJA@mail.gmail.com/T/#m6519cb07cfda08adf1dedea6596bb98892b4d5dcSigned-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    
    Changes since v7: (Arnd):
     - Fix a typo found by Ben Hutchings
    
    Changes since v6: (Arnd):
     - Add a patch to update the API versions
     - Hide a timespec reference in #ifndef __KERNEL__ to remove the
       last reference to time_t
     - Use a more readable way to do padding and describe it in the
       changelog
     - Rebase to linux-5.5-rc1, changing include/sound/soc-component.h
       and sound/drivers/aloop.c as needed.
    
    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.
    df1d6ea0
pcm_lib.c 67.2 KB