Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

Block layer patches

- qcow2 spec: Rename "zlib" compression to "deflate"
- Honour graph read lock even in the main thread + prerequisite fixes
- aio-posix: do not nest poll handlers (fixes infinite recursion)
- Refactor QMP blockdev transactions
- graph-lock: Disable locking for now
- iotests/245: Check if 'compress' driver is available

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# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (21 commits)
  iotests: Test commit with iothreads and ongoing I/O
  nbd/server: Fix drained_poll to wake coroutine in right AioContext
  graph-lock: Disable locking for now
  tested: add test for nested aio_poll() in poll handlers
  aio-posix: do not nest poll handlers
  iotests/245: Check if 'compress' driver is available
  graph-lock: Honour read locks even in the main thread
  blockjob: Adhere to rate limit even when reentered early
  test-bdrv-drain: Call bdrv_co_unref() in coroutine context
  test-bdrv-drain: Take graph lock more selectively
  qemu-img: Take graph lock more selectively
  qcow2: Unlock the graph in qcow2_do_open() where necessary
  block/export: Fix null pointer dereference in error path
  block: Call .bdrv_co_create(_opts) unlocked
  docs/interop/qcow2.txt: fix description about "zlib" clusters
  blockdev: qmp_transaction: drop extra generic layer
  blockdev: use state.bitmap in block-dirty-bitmap-add action
  blockdev: transaction: refactor handling transaction properties
  blockdev: qmp_transaction: refactor loop to classic for
  blockdev: transactions: rename some things
  ...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 27 insertions, 6 deletions

diff --git a/io/channel.c b/io/channel.c
index 375a130..72f0066 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -19,6 +19,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "block/aio-wait.h"
 #include "io/channel.h"
 #include "qapi/error.h"
 #include "qemu/main-loop.h"
@@ -514,7 +515,11 @@ int qio_channel_flush(QIOChannel *ioc,
 static void qio_channel_restart_read(void *opaque)
 {
     QIOChannel *ioc = opaque;
-    Coroutine *co = ioc->read_coroutine;
+    Coroutine *co = qatomic_xchg(&ioc->read_coroutine, NULL);
+
+    if (!co) {
+        return;
+    }
 
     /* Assert that aio_co_wake() reenters the coroutine directly */
     assert(qemu_get_current_aio_context() ==
@@ -525,7 +530,11 @@ static void qio_channel_restart_read(void *opaque)
 static void qio_channel_restart_write(void *opaque)
 {
     QIOChannel *ioc = opaque;
-    Coroutine *co = ioc->write_coroutine;
+    Coroutine *co = qatomic_xchg(&ioc->write_coroutine, NULL);
+
+    if (!co) {
+        return;
+    }
 
     /* Assert that aio_co_wake() reenters the coroutine directly */
     assert(qemu_get_current_aio_context() ==
@@ -568,7 +577,11 @@ void qio_channel_detach_aio_context(QIOChannel *ioc)
 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
                                     GIOCondition condition)
 {
+    AioContext *ioc_ctx = ioc->ctx ?: qemu_get_aio_context();
+
     assert(qemu_in_coroutine());
+    assert(in_aio_context_home_thread(ioc_ctx));
+
     if (condition == G_IO_IN) {
         assert(!ioc->read_coroutine);
         ioc->read_coroutine = qemu_coroutine_self();
@@ -580,18 +593,26 @@ void coroutine_fn qio_channel_yield(QIOChannel *ioc,
     }
     qio_channel_set_aio_fd_handlers(ioc);
     qemu_coroutine_yield();
+    assert(in_aio_context_home_thread(ioc_ctx));
 
     /* Allow interrupting the operation by reentering the coroutine other than
      * through the aio_fd_handlers. */
-    if (condition == G_IO_IN && ioc->read_coroutine) {
-        ioc->read_coroutine = NULL;
+    if (condition == G_IO_IN) {
+        assert(ioc->read_coroutine == NULL);
         qio_channel_set_aio_fd_handlers(ioc);
-    } else if (condition == G_IO_OUT && ioc->write_coroutine) {
-        ioc->write_coroutine = NULL;
+    } else if (condition == G_IO_OUT) {
+        assert(ioc->write_coroutine == NULL);
         qio_channel_set_aio_fd_handlers(ioc);
     }
 }
 
+void qio_channel_wake_read(QIOChannel *ioc)
+{
+    Coroutine *co = qatomic_xchg(&ioc->read_coroutine, NULL);
+    if (co) {
+        aio_co_wake(co);
+    }
+}
 
 static gboolean qio_channel_wait_complete(QIOChannel *ioc,
                                           GIOCondition condition,