[pulseaudio-discuss] [PATCH] memblock: Fix more block ID collisions

[David Henningsson]

Since the srb memblock and the audio data were coming from separate
pools, and the base index was per pool, they could actually still
collide.

This patch changes the base index to be global and atomically
incremented.

Reported-by: Arun Raghavan <arun at accosted.net>
Signed-off-by: David Henningsson <david.henningsson at canonical.com>
---
 src/pulsecore/memblock.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/pulsecore/memblock.c b/src/pulsecore/memblock.c
index b781312..d071a5f 100644
--- a/src/pulsecore/memblock.c
+++ b/src/pulsecore/memblock.c
@@ -151,7 +151,6 @@ struct pa_mempool {
     size_t block_size;
     unsigned n_blocks;
     bool is_remote_writable;
-    unsigned export_baseidx;
 
     pa_atomic_t n_init;
 
@@ -1088,6 +1087,8 @@ finish:
 pa_memexport* pa_memexport_new(pa_mempool *p, pa_memexport_revoke_cb_t cb, void *userdata) {
     pa_memexport *e;
 
+    static pa_atomic_t export_baseidx = PA_ATOMIC_INIT(0);
+
     pa_assert(p);
     pa_assert(cb);
 
@@ -1106,8 +1107,7 @@ pa_memexport* pa_memexport_new(pa_mempool *p, pa_memexport_revoke_cb_t cb, void
     pa_mutex_lock(p->mutex);
 
     PA_LLIST_PREPEND(pa_memexport, p->exports, e);
-    e->baseidx = p->export_baseidx;
-    p->export_baseidx += PA_MEMEXPORT_SLOTS_MAX;
+    e->baseidx = (uint32_t) pa_atomic_add(&export_baseidx, PA_MEMEXPORT_SLOTS_MAX);
 
     pa_mutex_unlock(p->mutex);
     return e;
-- 
1.9.1