MAJOR: threads/buffer: Make buffer wait queue thread safe

Adds a global lock to protect the buffer wait queue.

include/common/buffer.h

@@ -52,6 +52,9 @@ extern struct pool_head *pool2_buffer;
 extern struct buffer buf_empty;
 extern struct buffer buf_wanted;
 extern struct list buffer_wq;
+#ifdef USE_THREAD
+extern HA_SPINLOCK_T buffer_wq_lock;
+#endif
 
 int init_buffer();
 void deinit_buffer();
@@ -748,9 +751,13 @@ void __offer_buffer(void *from, unsigned int threshold);
 
 static inline void offer_buffers(void *from, unsigned int threshold)
 {
-	if (LIST_ISEMPTY(&buffer_wq))
+	SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
+	if (LIST_ISEMPTY(&buffer_wq)) {
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		return;
+	}
 	__offer_buffer(from, threshold);
+	SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 }
 
 /*************************************************************************/

include/common/hathreads.h

@@ -156,6 +156,7 @@ enum lock_label {
 	STK_SESS_LOCK,
 	APPLETS_LOCK,
 	PEER_LOCK,
+	BUF_WQ_LOCK,
 	LOCK_LABELS
 };
 struct lock_stat {
@@ -242,7 +243,7 @@ static inline void show_lock_stats()
 					   "TASK_RQ", "TASK_WQ", "POOL",
 					   "LISTENER", "LISTENER_QUEUE", "PROXY", "SERVER",
 					   "UPDATED_SERVERS", "LBPRM", "SIGNALS", "STK_TABLE", "STK_SESS",
-					   "APPLETS", "PEER" };
+					   "APPLETS", "PEER", "BUF_WQ" };
 	int lbl;
 
 	for (lbl = 0; lbl < LOCK_LABELS; lbl++) {

include/proto/applet.h

@@ -88,8 +88,10 @@ static inline void __appctx_free(struct appctx *appctx)
 	}
 
 	if (!LIST_ISEMPTY(&appctx->buffer_wait.list)) {
+		SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		LIST_DEL(&appctx->buffer_wait.list);
 		LIST_INIT(&appctx->buffer_wait.list);
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	}
 
 	pool_free2(pool2_connection, appctx);

include/proto/channel.h

@@ -440,8 +440,12 @@ static inline int channel_alloc_buffer(struct channel *chn, struct buffer_wait *
 	if (b_alloc_margin(&chn->buf, margin) != NULL)
 		return 1;
 
-	if (LIST_ISEMPTY(&wait->list))
+	if (LIST_ISEMPTY(&wait->list)) {
+		SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		LIST_ADDQ(&buffer_wq, &wait->list);
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
+	}
+
 	return 0;
 }
 

src/buffer.c

@@ -33,6 +33,9 @@ struct buffer buf_wanted = { .p = buf_wanted.data };
 
 /* list of objects waiting for at least one buffer */
 struct list buffer_wq = LIST_HEAD_INIT(buffer_wq);
+#ifdef USE_THREAD
+HA_SPINLOCK_T buffer_wq_lock;
+#endif
 
 /* this buffer is always the same size as standard buffers and is used for
  * swapping data inside a buffer.
@@ -72,6 +75,8 @@ int init_buffer()
 	if (global.tune.buf_limit)
 		pool2_buffer->limit = global.tune.buf_limit;
 
+	SPIN_INIT(&buffer_wq_lock);
+
 	buffer = pool_refill_alloc(pool2_buffer, pool2_buffer->minavail - 1);
 	if (!buffer)
 		return 0;

src/flt_spoe.c

@@ -18,6 +18,7 @@
 #include <common/debug.h>
 #include <common/memory.h>
 #include <common/time.h>
+#include <common/hathreads.h>
 
 #include <types/arg.h>
 #include <types/global.h>
@@ -2685,14 +2686,18 @@ spoe_acquire_buffer(struct buffer **buf, struct buffer_wait *buffer_wait)
 		return 1;
 
 	if (!LIST_ISEMPTY(&buffer_wait->list)) {
+		SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		LIST_DEL(&buffer_wait->list);
 		LIST_INIT(&buffer_wait->list);
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	}
 
 	if (b_alloc_margin(buf, global.tune.reserved_bufs))
 		return 1;
 
+	SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	LIST_ADDQ(&buffer_wq, &buffer_wait->list);
+	SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	return 0;
 }
 
@@ -2700,8 +2705,10 @@ static void
 spoe_release_buffer(struct buffer **buf, struct buffer_wait *buffer_wait)
 {
 	if (!LIST_ISEMPTY(&buffer_wait->list)) {
+		SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		LIST_DEL(&buffer_wait->list);
 		LIST_INIT(&buffer_wait->list);
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	}
 
 	/* Release the buffer if needed */

src/stream.c

@@ -320,8 +320,10 @@ static void stream_free(struct stream *s)
 
 	/* We may still be present in the buffer wait queue */
 	if (!LIST_ISEMPTY(&s->buffer_wait.list)) {
+		SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		LIST_DEL(&s->buffer_wait.list);
 		LIST_INIT(&s->buffer_wait.list);
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	}
 	if (s->req.buf->size || s->res.buf->size) {
 		b_drop(&s->req.buf);
@@ -415,14 +417,18 @@ static void stream_free(struct stream *s)
 static int stream_alloc_work_buffer(struct stream *s)
 {
 	if (!LIST_ISEMPTY(&s->buffer_wait.list)) {
+		SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 		LIST_DEL(&s->buffer_wait.list);
 		LIST_INIT(&s->buffer_wait.list);
+		SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	}
 
 	if (b_alloc_margin(&s->res.buf, 0))
 		return 1;
 
+	SPIN_LOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	LIST_ADDQ(&buffer_wq, &s->buffer_wait.list);
+	SPIN_UNLOCK(BUF_WQ_LOCK, &buffer_wq_lock);
 	return 0;
 }