block/reqlist: add reqlist_wait_all()

Add function to wait for all intersecting requests.
To be used in the further commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Nikita Lapshin <nikita.lapshin@virtuozzo.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220303194349.2304213-10-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

diff --git a/block/reqlist.c b/block/reqlist.c
index 09fecbd..08cb57c 100644 (file)
--- a/block/reqlist.c
+++ b/block/reqlist.c
@@ -58,6 +58,14 @@ bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset,
     return true;
 }
 
+void coroutine_fn reqlist_wait_all(BlockReqList *reqs, int64_t offset,
+                                   int64_t bytes, CoMutex *lock)
+{
+    while (reqlist_wait_one(reqs, offset, bytes, lock)) {
+        /* continue */
+    }
+}
+
 void coroutine_fn reqlist_shrink_req(BlockReq *req, int64_t new_bytes)
 {
     if (new_bytes == req->bytes) {

diff --git a/include/block/reqlist.h b/include/block/reqlist.h
index 0fa1eef..5253497 100644 (file)
--- a/include/block/reqlist.h
+++ b/include/block/reqlist.h
@@ -54,6 +54,14 @@ bool coroutine_fn reqlist_wait_one(BlockReqList *reqs, int64_t offset,
                                    int64_t bytes, CoMutex *lock);
 
 /*
+ * Wait for all intersecting requests. It just calls reqlist_wait_one() in a
+ * loop, caller is responsible to stop producing new requests in this region
+ * in parallel, otherwise reqlist_wait_all() may never return.
+ */
+void coroutine_fn reqlist_wait_all(BlockReqList *reqs, int64_t offset,
+                                   int64_t bytes, CoMutex *lock);
+
+/*
  * Shrink request and wake all waiting coroutines (maybe some of them are not
  * intersecting with shrunk request).
  */