block: use aio_bh_schedule_oneshot

This simplifies bottom half handlers by removing calls to qemu_bh_delete and
thus removing the need to stash the bottom half pointer in the opaque
datum.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

14 files changed, 27 insertions, 81 deletions

diff --git a/block/archipelago.c b/block/archipelago.c
index 37b8aca78d..2449cfc702 100644
--- a/block/archipelago.c
+++ b/block/archipelago.c
@@ -87,7 +87,6 @@ typedef enum {
 
 typedef struct ArchipelagoAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
     struct BDRVArchipelagoState *s;
     QEMUIOVector *qiov;
     ARCHIPCmd cmd;
@@ -154,11 +153,10 @@ static void archipelago_finish_aiocb(AIORequestData *reqdata)
     } else if (reqdata->aio_cb->ret == reqdata->segreq->total) {
         reqdata->aio_cb->ret = 0;
     }
-    reqdata->aio_cb->bh = aio_bh_new(
+    aio_bh_schedule_oneshot(
                         bdrv_get_aio_context(reqdata->aio_cb->common.bs),
                         qemu_archipelago_complete_aio, reqdata
                         );
-    qemu_bh_schedule(reqdata->aio_cb->bh);
 }
 
 static int wait_reply(struct xseg *xseg, xport srcport, struct xseg_port *port,
@@ -313,7 +311,6 @@ static void qemu_archipelago_complete_aio(void *opaque)
     AIORequestData *reqdata = (AIORequestData *) opaque;
     ArchipelagoAIOCB *aio_cb = (ArchipelagoAIOCB *) reqdata->aio_cb;
 
-    qemu_bh_delete(aio_cb->bh);
     aio_cb->common.cb(aio_cb->common.opaque, aio_cb->ret);
     aio_cb->status = 0;
 
diff --git a/block/blkdebug.c b/block/blkdebug.c
index d5db166815..4127571454 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -49,7 +49,6 @@ typedef struct BDRVBlkdebugState {
 
 typedef struct BlkdebugAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
     int ret;
 } BlkdebugAIOCB;
 
@@ -410,7 +409,6 @@ out:
 static void error_callback_bh(void *opaque)
 {
     struct BlkdebugAIOCB *acb = opaque;
-    qemu_bh_delete(acb->bh);
     acb->common.cb(acb->common.opaque, acb->ret);
     qemu_aio_unref(acb);
 }
@@ -421,7 +419,6 @@ static BlockAIOCB *inject_error(BlockDriverState *bs,
     BDRVBlkdebugState *s = bs->opaque;
     int error = rule->options.inject.error;
     struct BlkdebugAIOCB *acb;
-    QEMUBH *bh;
     bool immediately = rule->options.inject.immediately;
 
     if (rule->options.inject.once) {
@@ -436,9 +433,7 @@ static BlockAIOCB *inject_error(BlockDriverState *bs,
     acb = qemu_aio_get(&blkdebug_aiocb_info, bs, cb, opaque);
     acb->ret = -error;
 
-    bh = aio_bh_new(bdrv_get_aio_context(bs), error_callback_bh, acb);
-    acb->bh = bh;
-    qemu_bh_schedule(bh);
+    aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), error_callback_bh, acb);
 
     return &acb->common;
 }
diff --git a/block/blkverify.c b/block/blkverify.c
index da62d75969..28f9af6dba 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -22,7 +22,6 @@ typedef struct {
 typedef struct BlkverifyAIOCB BlkverifyAIOCB;
 struct BlkverifyAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
 
     /* Request metadata */
     bool is_write;
@@ -175,7 +174,6 @@ static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,
 {
     BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aiocb_info, bs, cb, opaque);
 
-    acb->bh = NULL;
     acb->is_write = is_write;
     acb->sector_num = sector_num;
     acb->nb_sectors = nb_sectors;
@@ -191,7 +189,6 @@ static void blkverify_aio_bh(void *opaque)
 {
     BlkverifyAIOCB *acb = opaque;
 
-    qemu_bh_delete(acb->bh);
     if (acb->buf) {
         qemu_iovec_destroy(&acb->raw_qiov);
         qemu_vfree(acb->buf);
@@ -218,9 +215,8 @@ static void blkverify_aio_cb(void *opaque, int ret)
             acb->verify(acb);
         }
 
-        acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs),
-                             blkverify_aio_bh, acb);
-        qemu_bh_schedule(acb->bh);
+        aio_bh_schedule_oneshot(bdrv_get_aio_context(acb->common.bs),
+                                blkverify_aio_bh, acb);
         break;
     }
 }
diff --git a/block/block-backend.c b/block/block-backend.c
index 639294b8e6..11b0d8b4c1 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -65,7 +65,6 @@ struct BlockBackend {
 
 typedef struct BlockBackendAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
     BlockBackend *blk;
     int ret;
 } BlockBackendAIOCB;
@@ -898,7 +897,6 @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
 static void error_callback_bh(void *opaque)
 {
     struct BlockBackendAIOCB *acb = opaque;
-    qemu_bh_delete(acb->bh);
     acb->common.cb(acb->common.opaque, acb->ret);
     qemu_aio_unref(acb);
 }
@@ -908,16 +906,12 @@ BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
                                   void *opaque, int ret)
 {
     struct BlockBackendAIOCB *acb;
-    QEMUBH *bh;
 
     acb = blk_aio_get(&block_backend_aiocb_info, blk, cb, opaque);
     acb->blk = blk;
     acb->ret = ret;
 
-    bh = aio_bh_new(blk_get_aio_context(blk), error_callback_bh, acb);
-    acb->bh = bh;
-    qemu_bh_schedule(bh);
-
+    aio_bh_schedule_oneshot(blk_get_aio_context(blk), error_callback_bh, acb);
     return &acb->common;
 }
 
@@ -926,7 +920,6 @@ typedef struct BlkAioEmAIOCB {
     BlkRwCo rwco;
     int bytes;
     bool has_returned;
-    QEMUBH* bh;
 } BlkAioEmAIOCB;
 
 static const AIOCBInfo blk_aio_em_aiocb_info = {
@@ -935,10 +928,6 @@ static const AIOCBInfo blk_aio_em_aiocb_info = {
 
 static void blk_aio_complete(BlkAioEmAIOCB *acb)
 {
-    if (acb->bh) {
-        assert(acb->has_returned);
-        qemu_bh_delete(acb->bh);
-    }
     if (acb->has_returned) {
         acb->common.cb(acb->common.opaque, acb->rwco.ret);
         qemu_aio_unref(acb);
@@ -947,7 +936,10 @@ static void blk_aio_complete(BlkAioEmAIOCB *acb)
 
 static void blk_aio_complete_bh(void *opaque)
 {
-    blk_aio_complete(opaque);
+    BlkAioEmAIOCB *acb = opaque;
+
+    assert(acb->has_returned);
+    blk_aio_complete(acb);
 }
 
 static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
@@ -967,7 +959,6 @@ static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
         .ret    = NOT_DONE,
     };
     acb->bytes = bytes;
-    acb->bh = NULL;
     acb->has_returned = false;
 
     co = qemu_coroutine_create(co_entry, acb);
@@ -975,8 +966,8 @@ static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
 
     acb->has_returned = true;
     if (acb->rwco.ret != NOT_DONE) {
-        acb->bh = aio_bh_new(blk_get_aio_context(blk), blk_aio_complete_bh, acb);
-        qemu_bh_schedule(acb->bh);
+        aio_bh_schedule_oneshot(blk_get_aio_context(blk),
+                                blk_aio_complete_bh, acb);
     }
 
     return &acb->common;
diff --git a/block/curl.c b/block/curl.c
index 571f24cac2..e5eaa7ba0a 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -96,7 +96,6 @@ struct BDRVCURLState;
 
 typedef struct CURLAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
     QEMUIOVector *qiov;
 
     int64_t sector_num;
@@ -739,9 +738,6 @@ static void curl_readv_bh_cb(void *p)
     CURLAIOCB *acb = p;
     BDRVCURLState *s = acb->common.bs->opaque;
 
-    qemu_bh_delete(acb->bh);
-    acb->bh = NULL;
-
     size_t start = acb->sector_num * SECTOR_SIZE;
     size_t end;
 
@@ -805,8 +801,7 @@ static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
     acb->sector_num = sector_num;
     acb->nb_sectors = nb_sectors;
 
-    acb->bh = aio_bh_new(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
-    qemu_bh_schedule(acb->bh);
+    aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);
     return &acb->common;
 }
 
diff --git a/block/gluster.c b/block/gluster.c
index e7bd13cce3..af76d7d59a 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -38,7 +38,6 @@
 typedef struct GlusterAIOCB {
     int64_t size;
     int ret;
-    QEMUBH *bh;
     Coroutine *coroutine;
     AioContext *aio_context;
 } GlusterAIOCB;
@@ -622,8 +621,6 @@ static void qemu_gluster_complete_aio(void *opaque)
 {
     GlusterAIOCB *acb = (GlusterAIOCB *)opaque;
 
-    qemu_bh_delete(acb->bh);
-    acb->bh = NULL;
     qemu_coroutine_enter(acb->coroutine);
 }
 
@@ -642,8 +639,7 @@ static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret, void *arg)
         acb->ret = -EIO; /* Partial read/write - fail it */
     }
 
-    acb->bh = aio_bh_new(acb->aio_context, qemu_gluster_complete_aio, acb);
-    qemu_bh_schedule(acb->bh);
+    aio_bh_schedule_oneshot(acb->aio_context, qemu_gluster_complete_aio, acb);
 }
 
 static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
diff --git a/block/io.c b/block/io.c
index 57a2eeb512..b136c89ae0 100644
--- a/block/io.c
+++ b/block/io.c
@@ -171,7 +171,6 @@ static void bdrv_drain_recurse(BlockDriverState *bs)
 typedef struct {
     Coroutine *co;
     BlockDriverState *bs;
-    QEMUBH *bh;
     bool done;
 } BdrvCoDrainData;
 
@@ -191,7 +190,6 @@ static void bdrv_co_drain_bh_cb(void *opaque)
     BdrvCoDrainData *data = opaque;
     Coroutine *co = data->co;
 
-    qemu_bh_delete(data->bh);
     bdrv_drain_poll(data->bs);
     data->done = true;
     qemu_coroutine_enter(co);
@@ -210,9 +208,9 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)
         .co = qemu_coroutine_self(),
         .bs = bs,
         .done = false,
-        .bh = aio_bh_new(bdrv_get_aio_context(bs), bdrv_co_drain_bh_cb, &data),
     };
-    qemu_bh_schedule(data.bh);
+    aio_bh_schedule_oneshot(bdrv_get_aio_context(bs),
+                            bdrv_co_drain_bh_cb, &data);
 
     qemu_coroutine_yield();
     /* If we are resumed from some other event (such as an aio completion or a
@@ -2095,7 +2093,6 @@ typedef struct BlockAIOCBCoroutine {
     bool is_write;
     bool need_bh;
     bool *done;
-    QEMUBH* bh;
 } BlockAIOCBCoroutine;
 
 static const AIOCBInfo bdrv_em_co_aiocb_info = {
@@ -2115,7 +2112,6 @@ static void bdrv_co_em_bh(void *opaque)
     BlockAIOCBCoroutine *acb = opaque;
 
     assert(!acb->need_bh);
-    qemu_bh_delete(acb->bh);
     bdrv_co_complete(acb);
 }
 
@@ -2125,8 +2121,7 @@ static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb)
     if (acb->req.error != -EINPROGRESS) {
         BlockDriverState *bs = acb->common.bs;
 
-        acb->bh = aio_bh_new(bdrv_get_aio_context(bs), bdrv_co_em_bh, acb);
-        qemu_bh_schedule(acb->bh);
+        aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), bdrv_co_em_bh, acb);
     }
 }
 
diff --git a/block/iscsi.c b/block/iscsi.c
index dff548a139..46ddc355ac 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -95,7 +95,6 @@ typedef struct IscsiTask {
     int do_retry;
     struct scsi_task *task;
     Coroutine *co;
-    QEMUBH *bh;
     IscsiLun *iscsilun;
     QEMUTimer retry_timer;
     int err_code;
@@ -167,7 +166,6 @@ static void iscsi_co_generic_bh_cb(void *opaque)
 {
     struct IscsiTask *iTask = opaque;
     iTask->complete = 1;
-    qemu_bh_delete(iTask->bh);
     qemu_coroutine_enter(iTask->co);
 }
 
@@ -299,9 +297,8 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
 
 out:
     if (iTask->co) {
-        iTask->bh = aio_bh_new(iTask->iscsilun->aio_context,
-                               iscsi_co_generic_bh_cb, iTask);
-        qemu_bh_schedule(iTask->bh);
+        aio_bh_schedule_oneshot(iTask->iscsilun->aio_context,
+                                 iscsi_co_generic_bh_cb, iTask);
     } else {
         iTask->complete = 1;
     }
diff --git a/block/nfs.c b/block/nfs.c
index 8602a44211..c3db2ec58d 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -57,7 +57,6 @@ typedef struct NFSRPC {
     QEMUIOVector *iov;
     struct stat *st;
     Coroutine *co;
-    QEMUBH *bh;
     NFSClient *client;
 } NFSRPC;
 
@@ -103,7 +102,6 @@ static void nfs_co_generic_bh_cb(void *opaque)
 {
     NFSRPC *task = opaque;
     task->complete = 1;
-    qemu_bh_delete(task->bh);
     qemu_coroutine_enter(task->co);
 }
 
@@ -127,9 +125,8 @@ nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,
         error_report("NFS Error: %s", nfs_get_error(nfs));
     }
     if (task->co) {
-        task->bh = aio_bh_new(task->client->aio_context,
-                              nfs_co_generic_bh_cb, task);
-        qemu_bh_schedule(task->bh);
+        aio_bh_schedule_oneshot(task->client->aio_context,
+                                nfs_co_generic_bh_cb, task);
     } else {
         task->complete = 1;
     }
diff --git a/block/null.c b/block/null.c
index b511010ba5..b300390944 100644
--- a/block/null.c
+++ b/block/null.c
@@ -124,7 +124,6 @@ static coroutine_fn int null_co_flush(BlockDriverState *bs)
 
 typedef struct {
     BlockAIOCB common;
-    QEMUBH *bh;
     QEMUTimer timer;
 } NullAIOCB;
 
@@ -136,7 +135,6 @@ static void null_bh_cb(void *opaque)
 {
     NullAIOCB *acb = opaque;
     acb->common.cb(acb->common.opaque, 0);
-    qemu_bh_delete(acb->bh);
     qemu_aio_unref(acb);
 }
 
@@ -164,8 +162,7 @@ static inline BlockAIOCB *null_aio_common(BlockDriverState *bs,
         timer_mod_ns(&acb->timer,
                      qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + s->latency_ns);
     } else {
-        acb->bh = aio_bh_new(bdrv_get_aio_context(bs), null_bh_cb, acb);
-        qemu_bh_schedule(acb->bh);
+        aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), null_bh_cb, acb);
     }
     return &acb->common;
 }
diff --git a/block/qed.c b/block/qed.c
index 426f3cb447..3ee879b52e 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -909,7 +909,6 @@ static void qed_aio_complete_bh(void *opaque)
     void *user_opaque = acb->common.opaque;
     int ret = acb->bh_ret;
 
-    qemu_bh_delete(acb->bh);
     qemu_aio_unref(acb);
 
     /* Invoke callback */
@@ -934,9 +933,8 @@ static void qed_aio_complete(QEDAIOCB *acb, int ret)
 
     /* Arrange for a bh to invoke the completion function */
     acb->bh_ret = ret;
-    acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs),
-                         qed_aio_complete_bh, acb);
-    qemu_bh_schedule(acb->bh);
+    aio_bh_schedule_oneshot(bdrv_get_aio_context(acb->common.bs),
+                            qed_aio_complete_bh, acb);
 
     /* Start next allocating write request waiting behind this one.  Note that
      * requests enqueue themselves when they first hit an unallocated cluster
diff --git a/block/qed.h b/block/qed.h
index 22b3198751..9676ab9479 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -130,7 +130,6 @@ enum {
 
 typedef struct QEDAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
     int bh_ret;                     /* final return status for completion bh */
     QSIMPLEQ_ENTRY(QEDAIOCB) next;  /* next request */
     int flags;                      /* QED_AIOCB_* bits ORed together */
diff --git a/block/rbd.c b/block/rbd.c
index 0106fea45f..6f9eb6fb9c 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -71,7 +71,6 @@ typedef enum {
 
 typedef struct RBDAIOCB {
     BlockAIOCB common;
-    QEMUBH *bh;
     int64_t ret;
     QEMUIOVector *qiov;
     char *bounce;
@@ -602,7 +601,6 @@ static const AIOCBInfo rbd_aiocb_info = {
 static void rbd_finish_bh(void *opaque)
 {
     RADOSCB *rcb = opaque;
-    qemu_bh_delete(rcb->acb->bh);
     qemu_rbd_complete_aio(rcb);
 }
 
@@ -621,9 +619,8 @@ static void rbd_finish_aiocb(rbd_completion_t c, RADOSCB *rcb)
     rcb->ret = rbd_aio_get_return_value(c);
     rbd_aio_release(c);
 
-    acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs),
-                         rbd_finish_bh, rcb);
-    qemu_bh_schedule(acb->bh);
+    aio_bh_schedule_oneshot(bdrv_get_aio_context(acb->common.bs),
+                            rbd_finish_bh, rcb);
 }
 
 static int rbd_aio_discard_wrapper(rbd_image_t image,
@@ -679,7 +676,6 @@ static BlockAIOCB *rbd_start_aio(BlockDriverState *bs,
     acb->ret = 0;
     acb->error = 0;
     acb->s = s;
-    acb->bh = NULL;
 
     if (cmd == RBD_AIO_WRITE) {
         qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
diff --git a/blockjob.c b/blockjob.c
index a167f96fd4..43fecbe13e 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -588,7 +588,6 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
 
 typedef struct {
     BlockJob *job;
-    QEMUBH *bh;
     AioContext *aio_context;
     BlockJobDeferToMainLoopFn *fn;
     void *opaque;
@@ -599,8 +598,6 @@ static void block_job_defer_to_main_loop_bh(void *opaque)
     BlockJobDeferToMainLoopData *data = opaque;
     AioContext *aio_context;
 
-    qemu_bh_delete(data->bh);
-
     /* Prevent race with block_job_defer_to_main_loop() */
     aio_context_acquire(data->aio_context);
 
@@ -624,13 +621,13 @@ void block_job_defer_to_main_loop(BlockJob *job,
 {
     BlockJobDeferToMainLoopData *data = g_malloc(sizeof(*data));
     data->job = job;
-    data->bh = qemu_bh_new(block_job_defer_to_main_loop_bh, data);
     data->aio_context = blk_get_aio_context(job->blk);
     data->fn = fn;
     data->opaque = opaque;
     job->deferred_to_main_loop = true;
 
-    qemu_bh_schedule(data->bh);
+    aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                            block_job_defer_to_main_loop_bh, data);
 }
 
 BlockJobTxn *block_job_txn_new(void)