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From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
	Emanuele Giuseppe Esposito <eesposit@redhat.com>,
	Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
	qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>, John Snow <jsnow@redhat.com>
Subject: [PATCH v3 2/5] block-copy: improve comments of BlockCopyTask and BlockCopyState types and functions
Date: Tue,  8 Jun 2021 09:33:41 +0200	[thread overview]
Message-ID: <20210608073344.53637-3-eesposit@redhat.com> (raw)
In-Reply-To: <20210608073344.53637-1-eesposit@redhat.com>

As done in BlockCopyCallState, categorize BlockCopyTask
and BlockCopyState in IN, State and OUT fields.
This is just to understand which field has to be protected with a lock.

.sleep_state is handled in the series "coroutine: new sleep/wake API"
and thus here left as TODO.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-copy.c | 47 ++++++++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/block/block-copy.c b/block/block-copy.c
index d58051288b..b3533a3003 100644
--- a/block/block-copy.c
+++ b/block/block-copy.c
@@ -56,25 +56,33 @@ typedef struct BlockCopyCallState {
     QLIST_ENTRY(BlockCopyCallState) list;
 
     /* State */
-    int ret;
     bool finished;
-    QemuCoSleep sleep;
-    bool cancelled;
+    QemuCoSleep sleep; /* TODO: protect API with a lock */
 
     /* OUT parameters */
+    bool cancelled;
     bool error_is_read;
+    int ret;
 } BlockCopyCallState;
 
 typedef struct BlockCopyTask {
     AioTask task;
 
+    /*
+     * IN parameters. Initialized in block_copy_task_create()
+     * and never changed.
+     */
     BlockCopyState *s;
     BlockCopyCallState *call_state;
     int64_t offset;
-    int64_t bytes;
-    BlockCopyMethod method;
-    QLIST_ENTRY(BlockCopyTask) list;
+    int64_t bytes; /* only re-set in task_shrink, before running the task */
+    BlockCopyMethod method; /* initialized in block_copy_dirty_clusters() */
+
+    /* State */
     CoQueue wait_queue; /* coroutines blocked on this task */
+
+    /* To reference all call states from BlockCopyState */
+    QLIST_ENTRY(BlockCopyTask) list;
 } BlockCopyTask;
 
 static int64_t task_end(BlockCopyTask *task)
@@ -90,15 +98,25 @@ typedef struct BlockCopyState {
      */
     BdrvChild *source;
     BdrvChild *target;
-    BdrvDirtyBitmap *copy_bitmap;
+
+    /* State */
     int64_t in_flight_bytes;
-    int64_t cluster_size;
     BlockCopyMethod method;
-    int64_t max_transfer;
-    uint64_t len;
     QLIST_HEAD(, BlockCopyTask) tasks; /* All tasks from all block-copy calls */
     QLIST_HEAD(, BlockCopyCallState) calls;
+    /* State fields that use a thread-safe API */
+    BdrvDirtyBitmap *copy_bitmap;
+    ProgressMeter *progress;
+    SharedResource *mem;
+    RateLimit rate_limit;
 
+    /*
+     * IN parameters. Initialized in block_copy_state_new()
+     * and never changed.
+     */
+    int64_t cluster_size;
+    int64_t max_transfer;
+    uint64_t len;
     BdrvRequestFlags write_flags;
 
     /*
@@ -114,14 +132,11 @@ typedef struct BlockCopyState {
      * In this case, block_copy() will query the source’s allocation status,
      * skip unallocated regions, clear them in the copy_bitmap, and invoke
      * block_copy_reset_unallocated() every time it does.
+     *
+     * This field is set in backup_run() before coroutines are run,
+     * therefore is an IN.
      */
     bool skip_unallocated;
-
-    ProgressMeter *progress;
-
-    SharedResource *mem;
-
-    RateLimit rate_limit;
 } BlockCopyState;
 
 static BlockCopyTask *find_conflicting_task(BlockCopyState *s,
-- 
2.30.2



  parent reply	other threads:[~2021-06-08  7:36 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08  7:33 [PATCH v3 0/5] block-copy: protect block-copy internal structures Emanuele Giuseppe Esposito
2021-06-08  7:33 ` [PATCH v3 1/5] block-copy: streamline choice of copy_range vs. read/write Emanuele Giuseppe Esposito
2021-06-09  8:51   ` Vladimir Sementsov-Ogievskiy
2021-06-09  9:33     ` Paolo Bonzini
2021-06-09 10:09       ` Vladimir Sementsov-Ogievskiy
2021-06-09 10:54       ` Vladimir Sementsov-Ogievskiy
2021-06-08  7:33 ` Emanuele Giuseppe Esposito [this message]
2021-06-09  9:12   ` [PATCH v3 2/5] block-copy: improve comments of BlockCopyTask and BlockCopyState types and functions Vladimir Sementsov-Ogievskiy
2021-06-10 10:14     ` Emanuele Giuseppe Esposito
2021-06-10 10:27       ` Vladimir Sementsov-Ogievskiy
2021-06-10 10:46         ` Emanuele Giuseppe Esposito
2021-06-10 11:12           ` Vladimir Sementsov-Ogievskiy
2021-06-10 14:21             ` Emanuele Giuseppe Esposito
2021-06-10 15:05               ` Vladimir Sementsov-Ogievskiy
2021-06-08  7:33 ` [PATCH v3 3/5] block-copy: move progress_set_remaining in block_copy_task_end Emanuele Giuseppe Esposito
2021-06-08  7:33 ` [PATCH v3 4/5] block-copy: add a CoMutex Emanuele Giuseppe Esposito
2021-06-09 12:25   ` Vladimir Sementsov-Ogievskiy
2021-06-10 14:49     ` Emanuele Giuseppe Esposito
2021-06-08  7:33 ` [PATCH v3 5/5] block-copy: atomic .cancelled and .finished fields in BlockCopyCallState Emanuele Giuseppe Esposito

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