[PATCH 07/12] block/io.c: introduce bdrv_subtree_drained_{begin/end}_unlocked

From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <fam@euphon.net>,
	Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	Emanuele Giuseppe Esposito <eesposit@redhat.com>,
	qemu-devel@nongnu.org, Hanna Reitz <hreitz@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, John Snow <jsnow@redhat.com>
Subject: [PATCH 07/12] block/io.c: introduce bdrv_subtree_drained_{begin/end}_unlocked
Date: Tue, 18 Jan 2022 11:27:33 -0500	[thread overview]
Message-ID: <20220118162738.1366281-8-eesposit@redhat.com> (raw)
In-Reply-To: <20220118162738.1366281-1-eesposit@redhat.com>

Same as the locked version, but use BDRV_POLL_UNLOCKED

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/io.c               | 50 +++++++++++++++++++++++++++++-----------
 include/block/block-io.h |  2 ++
 2 files changed, 39 insertions(+), 13 deletions(-)

diff --git a/block/io.c b/block/io.c
index 5123b7b713..9d5167f64a 100644
--- a/block/io.c
+++ b/block/io.c
@@ -244,6 +244,7 @@ typedef struct {
     bool begin;
     bool recursive;
     bool poll;
+    bool unlock;
     BdrvChild *parent;
     bool ignore_bds_parents;
     int *drained_end_counter;
@@ -334,7 +335,7 @@ static bool bdrv_drain_poll_top_level(BlockDriverState *bs, bool recursive,
 
 static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
                                   BdrvChild *parent, bool ignore_bds_parents,
-                                  bool poll);
+                                  bool poll, bool unlock);
 static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
                                 BdrvChild *parent, bool ignore_bds_parents,
                                 int *drained_end_counter);
@@ -352,7 +353,8 @@ static void bdrv_co_drain_bh_cb(void *opaque)
         if (data->begin) {
             assert(!data->drained_end_counter);
             bdrv_do_drained_begin(bs, data->recursive, data->parent,
-                                  data->ignore_bds_parents, data->poll);
+                                  data->ignore_bds_parents, data->poll,
+                                  data->unlock);
         } else {
             assert(!data->poll);
             bdrv_do_drained_end(bs, data->recursive, data->parent,
@@ -374,6 +376,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
                                                 BdrvChild *parent,
                                                 bool ignore_bds_parents,
                                                 bool poll,
+                                                bool unlock,
                                                 int *drained_end_counter)
 {
     BdrvCoDrainData data;
@@ -394,6 +397,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
         .parent = parent,
         .ignore_bds_parents = ignore_bds_parents,
         .poll = poll,
+        .unlock = unlock,
         .drained_end_counter = drained_end_counter,
     };
 
@@ -441,13 +445,13 @@ static void bdrv_do_drained_begin_quiesce(BlockDriverState *bs,
 
 static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
                                   BdrvChild *parent, bool ignore_bds_parents,
-                                  bool poll)
+                                  bool poll, bool unlock)
 {
     BdrvChild *child, *next;
 
     if (qemu_in_coroutine()) {
         bdrv_co_yield_to_drain(bs, true, recursive, parent, ignore_bds_parents,
-                               poll, NULL);
+                               poll, unlock, NULL);
         return;
     }
 
@@ -458,7 +462,7 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
         bs->recursive_quiesce_counter++;
         QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
             bdrv_do_drained_begin(child->bs, true, child, ignore_bds_parents,
-                                  false);
+                                  false, false);
         }
     }
 
@@ -473,23 +477,35 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, bool recursive,
      */
     if (poll) {
         assert(!ignore_bds_parents);
-        BDRV_POLL_WHILE(bs, bdrv_drain_poll_top_level(bs, recursive, parent));
+        if (unlock) {
+            BDRV_POLL_WHILE_UNLOCKED(bs,
+                                     bdrv_drain_poll_top_level(bs, recursive,
+                                                               parent));
+        } else {
+            BDRV_POLL_WHILE(bs,
+                            bdrv_drain_poll_top_level(bs, recursive, parent));
+        }
     }
 }
 
 void bdrv_drained_begin(BlockDriverState *bs)
 {
-    bdrv_do_drained_begin(bs, false, NULL, false, true);
+    bdrv_do_drained_begin(bs, false, NULL, false, true, false);
 }
 
 void bdrv_subtree_drained_begin(BlockDriverState *bs)
 {
-    bdrv_do_drained_begin(bs, true, NULL, false, true);
+    bdrv_do_drained_begin(bs, true, NULL, false, true, false);
+}
+
+void bdrv_subtree_drained_begin_unlocked(BlockDriverState *bs)
+{
+    bdrv_do_drained_begin(bs, true, NULL, false, true, true);
 }
 
 void bdrv_drained_begin_no_poll(BlockDriverState *bs)
 {
-    bdrv_do_drained_begin(bs, false, NULL, false, false);
+    bdrv_do_drained_begin(bs, false, NULL, false, false, false);
 }
 
 /**
@@ -517,7 +533,7 @@ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive,
 
     if (qemu_in_coroutine()) {
         bdrv_co_yield_to_drain(bs, false, recursive, parent, ignore_bds_parents,
-                               false, drained_end_counter);
+                               false, false, drained_end_counter);
         return;
     }
     assert(bs->quiesce_counter > 0);
@@ -561,12 +577,19 @@ void bdrv_subtree_drained_end(BlockDriverState *bs)
     BDRV_POLL_WHILE(bs, qatomic_read(&drained_end_counter) > 0);
 }
 
+void bdrv_subtree_drained_end_unlocked(BlockDriverState *bs)
+{
+    int drained_end_counter = 0;
+    bdrv_do_drained_end(bs, true, NULL, false, &drained_end_counter);
+    BDRV_POLL_WHILE_UNLOCKED(bs, qatomic_read(&drained_end_counter) > 0);
+}
+
 void bdrv_apply_subtree_drain(BdrvChild *child, BlockDriverState *new_parent)
 {
     int i;
 
     for (i = 0; i < new_parent->recursive_quiesce_counter; i++) {
-        bdrv_do_drained_begin(child->bs, true, child, false, true);
+        bdrv_do_drained_begin(child->bs, true, child, false, true, false);
     }
 }
 
@@ -651,7 +674,8 @@ void bdrv_drain_all_begin(void)
     assert(qemu_in_main_thread());
 
     if (qemu_in_coroutine()) {
-        bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true, NULL);
+        bdrv_co_yield_to_drain(NULL, true, false, NULL, true, true, false,
+                               NULL);
         return;
     }
 
@@ -676,7 +700,7 @@ void bdrv_drain_all_begin(void)
         AioContext *aio_context = bdrv_get_aio_context(bs);
 
         aio_context_acquire(aio_context);
-        bdrv_do_drained_begin(bs, false, NULL, true, false);
+        bdrv_do_drained_begin(bs, false, NULL, true, false, false);
         aio_context_release(aio_context);
     }
 
diff --git a/include/block/block-io.h b/include/block/block-io.h
index 34a991649c..a329ae24c1 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -253,6 +253,7 @@ void bdrv_drained_begin_no_poll(BlockDriverState *bs);
  * exclusive access to all child nodes as well.
  */
 void bdrv_subtree_drained_begin(BlockDriverState *bs);
+void bdrv_subtree_drained_begin_unlocked(BlockDriverState *bs);
 
 /**
  * bdrv_drained_end:
@@ -285,6 +286,7 @@ void bdrv_drained_end_no_poll(BlockDriverState *bs, int *drained_end_counter);
  * End a quiescent section started by bdrv_subtree_drained_begin().
  */
 void bdrv_subtree_drained_end(BlockDriverState *bs);
+void bdrv_subtree_drained_end_unlocked(BlockDriverState *bs);
 
 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
                                      uint32_t granularity, Error **errp);
-- 
2.31.1


