Merge remote-tracking branch 'remotes/stefanha-gitlab/tags/block-pull-request' into staging

Pull request

(Resent due to an email preparation mistake.)

# gpg: Signature made Mon 24 May 2021 14:01:42 BST
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha-gitlab/tags/block-pull-request:
  coroutine-sleep: introduce qemu_co_sleep
  coroutine-sleep: replace QemuCoSleepState pointer with struct in the API
  coroutine-sleep: move timer out of QemuCoSleepState
  coroutine-sleep: allow qemu_co_sleep_wake that wakes nothing
  coroutine-sleep: disallow NULL QemuCoSleepState** argument
  coroutine-sleep: use a stack-allocated timer
  bitops.h: Improve find_xxx_bit() documentation
  multi-process: Initialize variables declared with g_auto*

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 29 insertions, 13 deletions

diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
index 3acbf3384c..a72f69fea8 100644
--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -140,7 +140,8 @@ static inline int test_bit(long nr, const unsigned long *addr)
  * @addr: The address to start the search at
  * @size: The maximum size to search
  *
- * Returns the bit number of the first set bit, or size.
+ * Returns the bit number of the last set bit,
+ * or @size if there is no set bit in the bitmap.
  */
 unsigned long find_last_bit(const unsigned long *addr,
                             unsigned long size);
@@ -150,6 +151,9 @@ unsigned long find_last_bit(const unsigned long *addr,
  * @addr: The address to base the search on
  * @offset: The bitnumber to start searching at
  * @size: The bitmap size in bits
+ *
+ * Returns the bit number of the next set bit,
+ * or @size if there are no further set bits in the bitmap.
  */
 unsigned long find_next_bit(const unsigned long *addr,
                             unsigned long size,
@@ -160,6 +164,9 @@ unsigned long find_next_bit(const unsigned long *addr,
  * @addr: The address to base the search on
  * @offset: The bitnumber to start searching at
  * @size: The bitmap size in bits
+ *
+ * Returns the bit number of the next cleared bit,
+ * or @size if there are no further clear bits in the bitmap.
  */
 
 unsigned long find_next_zero_bit(const unsigned long *addr,
@@ -171,7 +178,8 @@ unsigned long find_next_zero_bit(const unsigned long *addr,
  * @addr: The address to start the search at
  * @size: The maximum size to search
  *
- * Returns the bit number of the first set bit.
+ * Returns the bit number of the first set bit,
+ * or @size if there is no set bit in the bitmap.
  */
 static inline unsigned long find_first_bit(const unsigned long *addr,
                                            unsigned long size)
@@ -194,7 +202,8 @@ static inline unsigned long find_first_bit(const unsigned long *addr,
  * @addr: The address to start the search at
  * @size: The maximum size to search
  *
- * Returns the bit number of the first cleared bit.
+ * Returns the bit number of the first cleared bit,
+ * or @size if there is no clear bit in the bitmap.
  */
 static inline unsigned long find_first_zero_bit(const unsigned long *addr,
                                                 unsigned long size)
diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index ce5b9c6851..292e61aef0 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -291,20 +291,27 @@ void qemu_co_rwlock_wrlock(CoRwlock *lock);
  */
 void qemu_co_rwlock_unlock(CoRwlock *lock);
 
-typedef struct QemuCoSleepState QemuCoSleepState;
+typedef struct QemuCoSleep {
+    Coroutine *to_wake;
+} QemuCoSleep;
 
 /**
- * Yield the coroutine for a given duration. During this yield, @sleep_state
- * (if not NULL) is set to an opaque pointer, which may be used for
- * qemu_co_sleep_wake(). Be careful, the pointer is set back to zero when the
- * timer fires. Don't save the obtained value to other variables and don't call
- * qemu_co_sleep_wake from another aio context.
+ * Yield the coroutine for a given duration. Initializes @w so that,
+ * during this yield, it can be passed to qemu_co_sleep_wake() to
+ * terminate the sleep.
  */
-void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns,
-                                            QemuCoSleepState **sleep_state);
+void coroutine_fn qemu_co_sleep_ns_wakeable(QemuCoSleep *w,
+                                            QEMUClockType type, int64_t ns);
+
+/**
+ * Yield the coroutine until the next call to qemu_co_sleep_wake.
+ */
+void coroutine_fn qemu_co_sleep(QemuCoSleep *w);
+
 static inline void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns)
 {
-    qemu_co_sleep_ns_wakeable(type, ns, NULL);
+    QemuCoSleep w = { 0 };
+    qemu_co_sleep_ns_wakeable(&w, type, ns);
 }
 
 /**
@@ -313,7 +320,7 @@ static inline void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns)
  * qemu_co_sleep_ns() and should be checked to be non-NULL before calling
  * qemu_co_sleep_wake().
  */
-void qemu_co_sleep_wake(QemuCoSleepState *sleep_state);
+void qemu_co_sleep_wake(QemuCoSleep *w);
 
 /**
  * Yield until a file descriptor becomes readable