staging: line6: avoid __sync_fetch_and_{and,or}
__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>
diff --git a/drivers/staging/line6/pcm.c b/drivers/staging/line6/pcm.c
index 02f77d7..4795f12 100644
--- a/drivers/staging/line6/pcm.c
+++ b/drivers/staging/line6/pcm.c
@@ -107,11 +107,15 @@
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 @@
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);