From a6ab7c875b0a03cbbd597067d8643ffea281aaaf Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Sat, 11 Dec 2010 00:04:30 +1100
Subject: [PATCH] Limit the number of threads decompressing stream 0 to just 1
 since it's always followed by stream 1 chunks, and it may lead to failure to
 decompress due to running out of memory by running too many threads.

---
 rzip.h   |  1 +
 stream.c | 14 +++++++++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/rzip.h b/rzip.h
index 2b4c062..03955c2 100644
--- a/rzip.h
+++ b/rzip.h
@@ -274,6 +274,7 @@ struct stream {
 	long uthread_no;
 	long unext_thread;
 	long base_thread;
+	int total_threads;
 };
 
 struct stream_info {
diff --git a/stream.c b/stream.c
index 80c12b3..b49c469 100644
--- a/stream.c
+++ b/stream.c
@@ -789,7 +789,7 @@ void *open_stream_in(int f, int n)
 	if (unlikely(!sinfo))
 		return NULL;
 
-	total_threads = control.threads * n;
+	total_threads = control.threads + 1;
 	threads = calloc(sizeof(pthread_t), total_threads);
 	if (unlikely(!threads))
 		return NULL;
@@ -815,11 +815,14 @@ void *open_stream_in(int f, int n)
 		return NULL;
 	}
 
+	sinfo->s[0].total_threads = 1;
+	sinfo->s[1].total_threads = control.threads;
+
 	for (i = 0; i < n; i++) {
 		uchar c;
 		i64 v1, v2;
 
-		sinfo->s[i].base_thread = control.threads * i;
+		sinfo->s[i].base_thread = i;
 		sinfo->s[i].uthread_no = sinfo->s[i].base_thread;
 		sinfo->s[i].unext_thread = sinfo->s[i].base_thread;
 
@@ -1104,9 +1107,10 @@ fill_another:
 	if (!last_head)
 		s->eos = 1;
 
-	if (++s->uthread_no == s->base_thread + control.threads)
+	if (++s->uthread_no == s->base_thread + s->total_threads)
 		s->uthread_no = s->base_thread;
-	if (!trywait_sem(&ucthread[s->uthread_no].free)) {
+	if (s->uthread_no != s->unext_thread &&
+	    !trywait_sem(&ucthread[s->uthread_no].free)) {
 		post_sem(&ucthread[s->uthread_no].free);
 		goto fill_another;
 	}
@@ -1119,7 +1123,7 @@ out:
 
 	post_sem(&ucthread[s->unext_thread].ready);
 
-	if (++s->unext_thread == s->base_thread + control.threads)
+	if (++s->unext_thread == s->base_thread + s->total_threads)
 		s->unext_thread = s->base_thread;
 
 	return 0;