staging: line6: avoid __sync_fetch_and_{and,or} (9f613601) · Commits · 戴 / test

__sync_fetch_and_and and __sync_fetch_and_or are functions that are provided by gcc and depending on the target architecture may be implemented in libgcc, which is not always available in the kernel. This leads to a build failure on ARMv5: drivers/built-in.o: In function `line6_pcm_release': :(.text+0x3bfe80): undefined reference to `__sync_fetch_and_and_4' drivers/built-in.o: In function `line6_pcm_acquire': :(.text+0x3bff30): undefined reference to `__sync_fetch_and_or_4' To work around this, we can use the kernel-provided cmpxchg macro. Build-tested only. Signed-off-by:

Arnd Bergmann <arnd@arndb.de> Cc: Markus Grabner <grabner@icg.tugraz.at> Acked-by:

Randy Dunlap <rdunlap@infradead.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/line6/pcm.c

+15 −8

Original line number	Diff line number	Diff line
		@@ -107,11 +107,15 @@ static bool test_flags(unsigned long flags0, unsigned long flags1,

		int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels)
		{
		unsigned long flags_old =
		__sync_fetch_and_or(&line6pcm->flags, channels);
		unsigned long flags_new = flags_old \| channels;
		unsigned long flags_final = flags_old;
		int err = 0;
		unsigned long flags_old, flags_new, flags_final;
		int err;

		do {
		flags_old = ACCESS_ONCE(line6pcm->flags);
		flags_new = flags_old \| channels;
		} while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);

		flags_final = flags_old;

		line6pcm->prev_fbuf = NULL;

		@@ -197,9 +201,12 @@ pcm_acquire_error:

		int line6_pcm_release(struct snd_line6_pcm *line6pcm, int channels)
		{
		unsigned long flags_old =
		__sync_fetch_and_and(&line6pcm->flags, ~channels);
		unsigned long flags_new = flags_old & ~channels;
		unsigned long flags_old, flags_new;

		do {
		flags_old = ACCESS_ONCE(line6pcm->flags);
		flags_new = flags_old & ~channels;
		} while (cmpxchg(&line6pcm->flags, flags_old, flags_new) != flags_old);

		if (test_flags(flags_new, flags_old, LINE6_BITS_CAPTURE_STREAM))
		line6_unlink_audio_in_urbs(line6pcm);

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