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-rw-r--r--src/pulsecore/asyncq.c201
1 files changed, 113 insertions, 88 deletions
diff --git a/src/pulsecore/asyncq.c b/src/pulsecore/asyncq.c
index c966e7dd..025c695e 100644
--- a/src/pulsecore/asyncq.c
+++ b/src/pulsecore/asyncq.c
@@ -52,9 +52,10 @@ struct pa_asyncq {
unsigned size;
unsigned read_idx;
unsigned write_idx;
- pa_atomic_t read_waiting, n_read;
- pa_atomic_t write_waiting, n_written;
+ pa_atomic_t read_waiting; /* a bool */
+ pa_atomic_t write_waiting; /* a bool */
int read_fds[2], write_fds[2];
+ pa_atomic_t in_read_fifo, in_write_fifo;
};
#define PA_ASYNCQ_CELLS(x) ((pa_atomic_ptr_t*) ((uint8_t*) (x) + PA_ALIGN(sizeof(struct pa_asyncq))))
@@ -80,8 +81,8 @@ pa_asyncq *pa_asyncq_new(unsigned size) {
l->size = size;
pa_atomic_store(&l->read_waiting, 0);
pa_atomic_store(&l->write_waiting, 0);
- pa_atomic_store(&l->n_written, 0);
- pa_atomic_store(&l->n_read, 0);
+ pa_atomic_store(&l->in_read_fifo, 0);
+ pa_atomic_store(&l->in_write_fifo, 0);
if (pipe(l->read_fds) < 0) {
pa_xfree(l);
@@ -133,68 +134,79 @@ int pa_asyncq_push(pa_asyncq*l, void *p, int wait) {
if (!pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) {
- if (!wait) {
- /* Let's empty the FIFO from old notifications, before we return */
+ /* Let's empty the FIFO from old notifications, before we return */
- while (pa_atomic_load(&l->n_read) > 0) {
- ssize_t r;
- int x[20];
-
- errno = 0;
- if ((r = read(l->write_fds[0], x, sizeof(x))) < 0 && errno != EINTR)
- return -1;
+ while (pa_atomic_load(&l->in_write_fifo) > 0) {
+ ssize_t r;
+ int x[20];
+
+ if ((r = read(l->write_fds[0], x, sizeof(x))) < 0) {
- pa_assert(r != 0);
+ if (errno == EINTR)
+ continue;
- if (r > 0)
- if (pa_atomic_sub(&l->n_read, r) <= r)
- break;
+ return -1;
}
-
- return -1;
- }
-
- /* First try failed. Let's wait for changes. */
- _Y;
+ pa_assert(r > 0);
+
+ if (pa_atomic_sub(&l->in_write_fifo, r) <= r)
+ break;
- pa_atomic_inc(&l->write_waiting);
+ }
- for (;;) {
- char x[20];
- ssize_t r;
+ /* Now let's make sure that we didn't lose any events */
+ if (!pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p)) {
- _Y;
+ if (!wait)
+ return -1;
- if (pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p))
- break;
+ /* Let's wait for changes. */
_Y;
- if ((r = read(l->write_fds[0], x, sizeof(x))) < 0 && errno != EINTR) {
- pa_atomic_dec(&l->write_waiting);
- return -1;
- }
+ pa_assert_se(pa_atomic_cmpxchg(&l->write_waiting, 0, 1));
- pa_assert(r != 0);
+ for (;;) {
+ char x[20];
+ ssize_t r;
+
+ _Y;
+
+ if (pa_atomic_ptr_cmpxchg(&cells[idx], NULL, p))
+ break;
+
+ _Y;
- if (r > 0)
- pa_atomic_sub(&l->n_read, r);
- }
+ if ((r = read(l->write_fds[0], x, sizeof(x))) < 0) {
- _Y;
+ if (errno == EINTR)
+ continue;
+
+ pa_assert_se(pa_atomic_cmpxchg(&l->write_waiting, 1, 0));
+ return -1;
+ }
- pa_atomic_dec(&l->write_waiting);
+ pa_assert(r > 0);
+ pa_atomic_sub(&l->in_write_fifo, r);
+ }
+
+ _Y;
+
+ pa_assert_se(pa_atomic_cmpxchg(&l->write_waiting, 1, 0));
+ }
}
_Y;
l->write_idx++;
- if (pa_atomic_load(&l->read_waiting)) {
+ if (pa_atomic_load(&l->read_waiting) > 0) {
char x = 'x';
_Y;
- if (write(l->read_fds[1], &x, sizeof(x)) > 0)
- pa_atomic_inc(&l->n_written);
+ if (write(l->read_fds[1], &x, sizeof(x)) > 0) {
+ pa_atomic_inc(&l->in_read_fifo);
+/* pa_log("increasing %p by 1", l); */
+ }
}
return 0;
@@ -206,7 +218,7 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
pa_atomic_ptr_t *cells;
pa_assert(l);
-
+
cells = PA_ASYNCQ_CELLS(l);
_Y;
@@ -214,71 +226,86 @@ void* pa_asyncq_pop(pa_asyncq*l, int wait) {
if (!(ret = pa_atomic_ptr_load(&cells[idx]))) {
- /* First try failed. Let's wait for changes. */
+/* pa_log("pop failed wait=%i", wait); */
- if (!wait) {
- /* Let's empty the FIFO from old notifications, before we return */
+ /* Hmm, nothing, here, so let's drop all queued events. */
+ while (pa_atomic_load(&l->in_read_fifo) > 0) {
+ ssize_t r;
+ int x[20];
- while (pa_atomic_load(&l->n_written) > 0) {
- ssize_t r;
- int x[20];
+ if ((r = read(l->read_fds[0], x, sizeof(x))) < 0) {
- errno = 0;
- if ((r = read(l->read_fds[0], x, sizeof(x))) < 0 && errno != EINTR)
- return NULL;
-
- pa_assert(r != 0);
+ if (errno == EINTR)
+ continue;
- if (r > 0)
- if (pa_atomic_sub(&l->n_written, r) <= r)
- break;
+ return NULL;
}
+
+ pa_assert(r > 0);
+
+/* pa_log("decreasing %p by %i", l, r); */
- return NULL;
+ if (pa_atomic_sub(&l->in_read_fifo, r) <= r)
+ break;
}
- _Y;
-
- pa_atomic_inc(&l->read_waiting);
+ /* Now let's make sure that we didn't lose any events */
+ if (!(ret = pa_atomic_ptr_load(&cells[idx]))) {
- for (;;) {
- char x[20];
- ssize_t r;
+ if (!wait)
+ return NULL;
+ /* Let's wait for changes. */
+
_Y;
+
+ pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 0, 1));
+
+ for (;;) {
+ char x[20];
+ ssize_t r;
+
+ _Y;
+
+ if ((ret = pa_atomic_ptr_load(&cells[idx])))
+ break;
+
+ _Y;
+
+ if ((r = read(l->read_fds[0], x, sizeof(x))) < 0) {
- if ((ret = pa_atomic_ptr_load(&cells[idx])))
- break;
-
- _Y;
+ if (errno == EINTR)
+ continue;
+
+ pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
+ return NULL;
+ }
- if ((r = read(l->read_fds[0], x, sizeof(x))) < 0 && errno != EINTR) {
- pa_atomic_dec(&l->read_waiting);
- return NULL;
+/* pa_log("decreasing %p by %i", l, r); */
+
+ pa_assert(r > 0);
+ pa_atomic_sub(&l->in_read_fifo, r);
}
- pa_assert(r != 0);
+ _Y;
- if (r > 0)
- pa_atomic_sub(&l->n_written, r);
+ pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
}
-
- _Y;
-
- pa_atomic_dec(&l->read_waiting);
}
+ pa_assert(ret);
+
/* Guaranteed if we only have a single reader */
pa_assert_se(pa_atomic_ptr_cmpxchg(&cells[idx], ret, NULL));
_Y;
l->read_idx++;
- if (pa_atomic_load(&l->write_waiting)) {
+ if (pa_atomic_load(&l->write_waiting) > 0) {
char x = 'x';
_Y;
if (write(l->write_fds[1], &x, sizeof(x)) >= 0)
- pa_atomic_inc(&l->n_read);
+ pa_atomic_inc(&l->in_write_fifo);
}
return ret;
@@ -301,13 +328,13 @@ int pa_asyncq_before_poll(pa_asyncq *l) {
_Y;
idx = reduce(l, l->read_idx);
- if (pa_atomic_ptr_load(&cells[idx]))
+ if (pa_atomic_ptr_load(&cells[idx]) || pa_atomic_load(&l->in_read_fifo) > 0)
return -1;
- pa_atomic_inc(&l->read_waiting);
+ pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 0, 1));
- if (pa_atomic_ptr_load(&cells[idx])) {
- pa_atomic_dec(&l->read_waiting);
+ if (pa_atomic_ptr_load(&cells[idx]) || pa_atomic_load(&l->in_read_fifo) > 0) {
+ pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
return -1;
}
@@ -317,7 +344,5 @@ int pa_asyncq_before_poll(pa_asyncq *l) {
void pa_asyncq_after_poll(pa_asyncq *l) {
pa_assert(l);
- pa_assert(pa_atomic_load(&l->read_waiting) > 0);
-
- pa_atomic_dec(&l->read_waiting);
+ pa_assert_se(pa_atomic_cmpxchg(&l->read_waiting, 1, 0));
}
generated by cgit (git 2.34.1) at 2025-10-31 14:24:10 +0000