[Qemu-devel] [PATCH 2/3] block: mirror - split out part of mirror_run()

[Jeff Cody]

This is code relocation, to pull the part of mirror_run() that
calls mirror_iteration out into a separate function.

Signed-off-by: Jeff Cody <address@hidden>
---
 block/mirror.c | 206 ++++++++++++++++++++++++++++++---------------------------
 1 file changed, 110 insertions(+), 96 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index 8b3e89b..405e5c4 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -318,6 +318,115 @@ static uint64_t coroutine_fn 
mirror_iteration(MirrorBlockJob *s)
     return delay_ns;
 }
 
+static int mirror_do_iteration(MirrorBlockJob *s, uint64_t last_pause_ns)
+{
+    int ret;
+
+    BlockDriverState *bs = s->common.bs;
+
+    for (;;) {
+        uint64_t delay_ns = 0;
+        int64_t cnt;
+        bool should_complete;
+
+        if (s->ret < 0) {
+            ret = s->ret;
+            goto immediate_exit;
+        }
+
+        cnt = bdrv_get_dirty_count(s->dirty_bitmap);
+        /* s->common.offset contains the number of bytes already processed so
+         * far, cnt is the number of dirty sectors remaining and
+         * s->sectors_in_flight is the number of sectors currently being
+         * processed; together those are the current total operation length */
+        s->common.len = s->common.offset +
+                        (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE;
+
+        /* Note that even when no rate limit is applied we need to yield
+         * periodically with no pending I/O so that bdrv_drain_all() returns.
+         * We do so every SLICE_TIME nanoseconds, or when there is an error,
+         * or when the source is clean, whichever comes first.
+         */
+        if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME
+            && s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
+            if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
+                (cnt == 0 && s->in_flight > 0)) {
+                trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
+                s->waiting_for_io = true;
+                qemu_coroutine_yield();
+                s->waiting_for_io = false;
+                continue;
+            } else if (cnt != 0) {
+                delay_ns = mirror_iteration(s);
+            }
+        }
+
+        should_complete = false;
+        if (s->in_flight == 0 && cnt == 0) {
+            trace_mirror_before_flush(s);
+            ret = bdrv_flush(s->target);
+            if (ret < 0) {
+                if (mirror_error_action(s, false, -ret) ==
+                    BLOCK_ERROR_ACTION_REPORT) {
+                    goto immediate_exit;
+                }
+            } else {
+                /* We're out of the streaming phase.  From now on, if the job
+                 * is cancelled we will actually complete all pending I/O and
+                 * report completion.  This way, block-job-cancel will leave
+                 * the target in a consistent state.
+                 */
+                if (!s->synced) {
+                    block_job_event_ready(&s->common);
+                    s->synced = true;
+                }
+
+                should_complete = s->should_complete ||
+                    block_job_is_cancelled(&s->common);
+                cnt = bdrv_get_dirty_count(s->dirty_bitmap);
+            }
+        }
+
+        if (cnt == 0 && should_complete) {
+            /* The dirty bitmap is not updated while operations are pending.
+             * If we're about to exit, wait for pending operations before
+             * calling bdrv_get_dirty_count(bs), or we may exit while the
+             * source has dirty data to copy!
+             *
+             * Note that I/O can be submitted by the guest while
+             * mirror_populate runs.
+             */
+            trace_mirror_before_drain(s, cnt);
+            bdrv_drain(bs);
+            cnt = bdrv_get_dirty_count(s->dirty_bitmap);
+        }
+
+        ret = 0;
+        trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
+        if (!s->synced) {
+            block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
+            if (block_job_is_cancelled(&s->common)) {
+                break;
+            }
+        } else if (!should_complete) {
+            delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
+            block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
+        } else if (cnt == 0) {
+            /* The two disks are in sync.  Exit and report successful
+             * completion.
+             */
+            assert(QLIST_EMPTY(&bs->tracked_requests));
+            s->common.cancelled = false;
+            break;
+        }
+        last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+    }
+
+immediate_exit:
+    return ret;
+
+}
+
 static void mirror_free_init(MirrorBlockJob *s)
 {
     int granularity = s->granularity;
@@ -485,103 +594,8 @@ static void coroutine_fn mirror_run(void *opaque)
     }
 
     bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
-    for (;;) {
-        uint64_t delay_ns = 0;
-        int64_t cnt;
-        bool should_complete;
 
-        if (s->ret < 0) {
-            ret = s->ret;
-            goto immediate_exit;
-        }
-
-        cnt = bdrv_get_dirty_count(s->dirty_bitmap);
-        /* s->common.offset contains the number of bytes already processed so
-         * far, cnt is the number of dirty sectors remaining and
-         * s->sectors_in_flight is the number of sectors currently being
-         * processed; together those are the current total operation length */
-        s->common.len = s->common.offset +
-                        (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE;
-
-        /* Note that even when no rate limit is applied we need to yield
-         * periodically with no pending I/O so that bdrv_drain_all() returns.
-         * We do so every SLICE_TIME nanoseconds, or when there is an error,
-         * or when the source is clean, whichever comes first.
-         */
-        if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < 
SLICE_TIME &&
-            s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
-            if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
-                (cnt == 0 && s->in_flight > 0)) {
-                trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
-                s->waiting_for_io = true;
-                qemu_coroutine_yield();
-                s->waiting_for_io = false;
-                continue;
-            } else if (cnt != 0) {
-                delay_ns = mirror_iteration(s);
-            }
-        }
-
-        should_complete = false;
-        if (s->in_flight == 0 && cnt == 0) {
-            trace_mirror_before_flush(s);
-            ret = bdrv_flush(s->target);
-            if (ret < 0) {
-                if (mirror_error_action(s, false, -ret) ==
-                    BLOCK_ERROR_ACTION_REPORT) {
-                    goto immediate_exit;
-                }
-            } else {
-                /* We're out of the streaming phase.  From now on, if the job
-                 * is cancelled we will actually complete all pending I/O and
-                 * report completion.  This way, block-job-cancel will leave
-                 * the target in a consistent state.
-                 */
-                if (!s->synced) {
-                    block_job_event_ready(&s->common);
-                    s->synced = true;
-                }
-
-                should_complete = s->should_complete ||
-                    block_job_is_cancelled(&s->common);
-                cnt = bdrv_get_dirty_count(s->dirty_bitmap);
-            }
-        }
-
-        if (cnt == 0 && should_complete) {
-            /* The dirty bitmap is not updated while operations are pending.
-             * If we're about to exit, wait for pending operations before
-             * calling bdrv_get_dirty_count(bs), or we may exit while the
-             * source has dirty data to copy!
-             *
-             * Note that I/O can be submitted by the guest while
-             * mirror_populate runs.
-             */
-            trace_mirror_before_drain(s, cnt);
-            bdrv_drain(bs);
-            cnt = bdrv_get_dirty_count(s->dirty_bitmap);
-        }
-
-        ret = 0;
-        trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
-        if (!s->synced) {
-            block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
-            if (block_job_is_cancelled(&s->common)) {
-                break;
-            }
-        } else if (!should_complete) {
-            delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
-            block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
-        } else if (cnt == 0) {
-            /* The two disks are in sync.  Exit and report successful
-             * completion.
-             */
-            assert(QLIST_EMPTY(&bs->tracked_requests));
-            s->common.cancelled = false;
-            break;
-        }
-        last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
-    }
+    ret = mirror_do_iteration(s, last_pause_ns);
 
 immediate_exit:
     if (s->in_flight > 0) {
-- 
1.9.3