[Qemu-devel] [PATCH] block/linux-aio: Drop unused BlockAIOCB submission method

[Julia Suvorova]

Callback-based laio_submit() and laio_cancel() were left after
rewriting Linux AIO backend to coroutines in hope that they would be
used in other code that could bypass coroutines. They can be safely
removed because they have not been used since that time.

Signed-off-by: Julia Suvorova <address@hidden>
---
 block/linux-aio.c       | 72 ++++++-----------------------------------
 include/block/raw-aio.h |  3 --
 2 files changed, 10 insertions(+), 65 deletions(-)

diff --git a/block/linux-aio.c b/block/linux-aio.c
index d4b61fb251..27100c2fd1 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -30,7 +30,6 @@
 #define MAX_EVENTS 128
 
 struct qemu_laiocb {
-    BlockAIOCB common;
     Coroutine *co;
     LinuxAioState *ctx;
     struct iocb iocb;
@@ -72,7 +71,7 @@ static inline ssize_t io_event_ret(struct io_event *ev)
 }
 
 /*
- * Completes an AIO request (calls the callback and frees the ACB).
+ * Completes an AIO request.
  */
 static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
 {
@@ -94,18 +93,15 @@ static void qemu_laio_process_completion(struct qemu_laiocb 
*laiocb)
     }
 
     laiocb->ret = ret;
-    if (laiocb->co) {
-        /* If the coroutine is already entered it must be in ioq_submit() and
-         * will notice laio->ret has been filled in when it eventually runs
-         * later.  Coroutines cannot be entered recursively so avoid doing
-         * that!
-         */
-        if (!qemu_coroutine_entered(laiocb->co)) {
-            aio_co_wake(laiocb->co);
-        }
-    } else {
-        laiocb->common.cb(laiocb->common.opaque, ret);
-        qemu_aio_unref(laiocb);
+
+    /*
+     * If the coroutine is already entered it must be in ioq_submit() and
+     * will notice laio->ret has been filled in when it eventually runs
+     * later.  Coroutines cannot be entered recursively so avoid doing
+     * that!
+     */
+    if (!qemu_coroutine_entered(laiocb->co)) {
+        aio_co_wake(laiocb->co);
     }
 }
 
@@ -273,30 +269,6 @@ static bool qemu_laio_poll_cb(void *opaque)
     return true;
 }
 
-static void laio_cancel(BlockAIOCB *blockacb)
-{
-    struct qemu_laiocb *laiocb = (struct qemu_laiocb *)blockacb;
-    struct io_event event;
-    int ret;
-
-    if (laiocb->ret != -EINPROGRESS) {
-        return;
-    }
-    ret = io_cancel(laiocb->ctx->ctx, &laiocb->iocb, &event);
-    laiocb->ret = -ECANCELED;
-    if (ret != 0) {
-        /* iocb is not cancelled, cb will be called by the event loop later */
-        return;
-    }
-
-    laiocb->common.cb(laiocb->common.opaque, laiocb->ret);
-}
-
-static const AIOCBInfo laio_aiocb_info = {
-    .aiocb_size         = sizeof(struct qemu_laiocb),
-    .cancel_async       = laio_cancel,
-};
-
 static void ioq_init(LaioQueue *io_q)
 {
     QSIMPLEQ_INIT(&io_q->pending);
@@ -431,30 +403,6 @@ int coroutine_fn laio_co_submit(BlockDriverState *bs, 
LinuxAioState *s, int fd,
     return laiocb.ret;
 }
 
-BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
-        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockCompletionFunc *cb, void *opaque, int type)
-{
-    struct qemu_laiocb *laiocb;
-    off_t offset = sector_num * BDRV_SECTOR_SIZE;
-    int ret;
-
-    laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque);
-    laiocb->nbytes = nb_sectors * BDRV_SECTOR_SIZE;
-    laiocb->ctx = s;
-    laiocb->ret = -EINPROGRESS;
-    laiocb->is_read = (type == QEMU_AIO_READ);
-    laiocb->qiov = qiov;
-
-    ret = laio_do_submit(fd, laiocb, offset, type);
-    if (ret < 0) {
-        qemu_aio_unref(laiocb);
-        return NULL;
-    }
-
-    return &laiocb->common;
-}
-
 void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
 {
     aio_set_event_notifier(old_context, &s->e, false, NULL, NULL);
diff --git a/include/block/raw-aio.h b/include/block/raw-aio.h
index ba223dd1f1..0cb7cc74a2 100644
--- a/include/block/raw-aio.h
+++ b/include/block/raw-aio.h
@@ -50,9 +50,6 @@ LinuxAioState *laio_init(Error **errp);
 void laio_cleanup(LinuxAioState *s);
 int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
                                 uint64_t offset, QEMUIOVector *qiov, int type);
-BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
-        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
-        BlockCompletionFunc *cb, void *opaque, int type);
 void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context);
 void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context);
 void laio_io_plug(BlockDriverState *bs, LinuxAioState *s);
-- 
2.17.1