On Thu, Nov 9, 2017 at 5:52 PM, Takashi Iwai tiwai@suse.de wrote:
On Mon, 06 Nov 2017 17:33:26 +0100,
--- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -306,10 +306,19 @@ typedef int __bitwise snd_pcm_state_t;
enum { SNDRV_PCM_MMAP_OFFSET_DATA = 0x00000000,
SNDRV_PCM_MMAP_OFFSET_STATUS = 0x80000000,
SNDRV_PCM_MMAP_OFFSET_STATUS_OLD = 0x80000000, SNDRV_PCM_MMAP_OFFSET_CONTROL = 0x81000000,SNDRV_PCM_MMAP_OFFSET_STATUS64 = 0x82000000,};
+#if __BITS_PER_LONG == 64 +#define SNDRV_PCM_MMAP_OFFSET_STATUS SNDRV_PCM_MMAP_OFFSET_STATUS_OLD +#else +#define SNDRV_PCM_MMAP_OFFSET_STATUS ((sizeof(time_t) > sizeof(__kernel_long_t)) ? \
SNDRV_PCM_MMAP_OFFSET_STATUS64 : \SNDRV_PCM_MMAP_OFFSET_STATUS_OLD)+#endif
union snd_pcm_sync_id { unsigned char id[16]; unsigned short id16[8];
Does that make sense?
Yeah, that should work.
But can we make the flip without the dynamic sizeof() comparison but some ifdef? The above doesn't allow the usage with switch(), for example.
IOW, is there any macro indicating the 64bit user time_t?
There is a macro defined by the C library, but so far we have not started relying on it in kernel headers, because there is no guarantee that this symbol is visible before sys/time.h has been included, and there are some cases where it's possible to include a kernel header before sys/time.h.
In case of sound/asound.h, that should be no problem since we rely on having seen the definition on 'struct timeval' already today, and that must come from sys/time.h. Then we just need to make sure that all C libraries define the same macro.
Are you sure about the switch()/case problem? I thought that worked in C99, the only problem would be using the macro outside of a function, e.g. as initalizer for a variable
In theory we can have the shadow mmap for the compat timespec, and convert it always when the status gets changed. But I guess disabling the mmap should work simply as is, judging from the 64bit compat status.
Ok.
Arnd