[PATCH v2 12/12] block/nvme: Use per-queue AIO context

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

To be able to use multiple queues on the same hardware,
we need to have each queue able to receive IRQ notifications
in the correct AIO context.
The AIO context and the notification handler have to be proper
to each queue, not to the block driver. Move aio_context and
irq_notifier from BDRVNVMeState to NVMeQueuePair.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
Since v1: Moved irq_notifier to NVMeQueuePair
---
 block/nvme.c | 71 +++++++++++++++++++++++++++-------------------------
 1 file changed, 37 insertions(+), 34 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index 90b2e00e8d..e7b9ecec41 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -60,6 +60,8 @@ typedef struct {
 
 typedef struct {
     QemuMutex   lock;
+    AioContext *aio_context;
+    EventNotifier irq_notifier;
 
     /* Read from I/O code path, initialized under BQL */
     BDRVNVMeState   *s;
@@ -107,7 +109,6 @@ QEMU_BUILD_BUG_ON(offsetof(NVMeRegs, doorbells) != 0x1000);
 #define QUEUE_INDEX_IO(n)   (1 + n)
 
 struct BDRVNVMeState {
-    AioContext *aio_context;
     QEMUVFIOState *vfio;
     NVMeRegs *regs;
     /* The submission/completion queue pairs.
@@ -120,7 +121,6 @@ struct BDRVNVMeState {
     /* How many uint32_t elements does each doorbell entry take. */
     size_t doorbell_scale;
     bool write_cache_supported;
-    EventNotifier irq_notifier;
 
     uint64_t nsze; /* Namespace size reported by identify command */
     int nsid;      /* The namespace id to read/write data. */
@@ -227,11 +227,17 @@ static NVMeQueuePair *nvme_create_queue_pair(BDRVNVMeState *s,
     if (!q->prp_list_pages) {
         goto fail;
     }
+    r = event_notifier_init(&q->irq_notifier, 0);
+    if (r) {
+        error_setg(errp, "Failed to init event notifier");
+        goto fail;
+    }
     memset(q->prp_list_pages, 0, s->page_size * NVME_QUEUE_SIZE);
     qemu_mutex_init(&q->lock);
     q->s = s;
     q->index = idx;
     qemu_co_queue_init(&q->free_req_queue);
+    q->aio_context = aio_context;
     q->completion_bh = aio_bh_new(aio_context, nvme_process_completion_bh, q);
     r = qemu_vfio_dma_map(s->vfio, q->prp_list_pages,
                           s->page_size * NVME_NUM_REQS,
@@ -325,7 +331,7 @@ static void nvme_put_free_req_locked(NVMeQueuePair *q, NVMeRequest *req)
 static void nvme_wake_free_req_locked(NVMeQueuePair *q)
 {
     if (!qemu_co_queue_empty(&q->free_req_queue)) {
-        replay_bh_schedule_oneshot_event(q->s->aio_context,
+        replay_bh_schedule_oneshot_event(q->aio_context,
                 nvme_free_req_queue_cb, q);
     }
 }
@@ -492,7 +498,6 @@ static void nvme_cmd_sync_cb(void *opaque, int ret)
 static int nvme_cmd_sync(BlockDriverState *bs, NVMeQueuePair *q,
                          NvmeCmd *cmd)
 {
-    AioContext *aio_context = bdrv_get_aio_context(bs);
     NVMeRequest *req;
     int ret = -EINPROGRESS;
     req = nvme_get_free_req(q);
@@ -501,7 +506,7 @@ static int nvme_cmd_sync(BlockDriverState *bs, NVMeQueuePair *q,
     }
     nvme_submit_command(q, req, cmd, nvme_cmd_sync_cb, &ret);
 
-    AIO_WAIT_WHILE(aio_context, ret == -EINPROGRESS);
+    AIO_WAIT_WHILE(q->aio_context, ret == -EINPROGRESS);
     return ret;
 }
 
@@ -621,14 +626,16 @@ static bool nvme_poll_queues(BDRVNVMeState *s)
 
 static void nvme_handle_event(EventNotifier *n)
 {
-    BDRVNVMeState *s = container_of(n, BDRVNVMeState, irq_notifier);
+    NVMeQueuePair *q = container_of(n, NVMeQueuePair, irq_notifier);
+    BDRVNVMeState *s = q->s;
 
     trace_nvme_handle_event(s);
     event_notifier_test_and_clear(n);
     nvme_poll_queues(s);
 }
 
-static bool nvme_add_io_queue(BlockDriverState *bs, Error **errp)
+static bool nvme_add_io_queue(BlockDriverState *bs,
+                              AioContext *aio_context, Error **errp)
 {
     BDRVNVMeState *s = bs->opaque;
     int n = s->nr_queues;
@@ -636,8 +643,7 @@ static bool nvme_add_io_queue(BlockDriverState *bs, Error **errp)
     NvmeCmd cmd;
     int queue_size = NVME_QUEUE_SIZE;
 
-    q = nvme_create_queue_pair(s, bdrv_get_aio_context(bs),
-                               n, queue_size, errp);
+    q = nvme_create_queue_pair(s, aio_context, n, queue_size, errp);
     if (!q) {
         return false;
     }
@@ -672,7 +678,8 @@ static bool nvme_add_io_queue(BlockDriverState *bs, Error **errp)
 static bool nvme_poll_cb(void *opaque)
 {
     EventNotifier *e = opaque;
-    BDRVNVMeState *s = container_of(e, BDRVNVMeState, irq_notifier);
+    NVMeQueuePair *q = container_of(e, NVMeQueuePair, irq_notifier);
+    BDRVNVMeState *s = q->s;
 
     trace_nvme_poll_cb(s);
     return nvme_poll_queues(s);
@@ -693,12 +700,6 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     qemu_co_queue_init(&s->dma_flush_queue);
     s->device = g_strdup(device);
     s->nsid = namespace;
-    s->aio_context = bdrv_get_aio_context(bs);
-    ret = event_notifier_init(&s->irq_notifier, 0);
-    if (ret) {
-        error_setg(errp, "Failed to init event notifier");
-        return ret;
-    }
 
     s->vfio = qemu_vfio_open_pci(device, errp);
     if (!s->vfio) {
@@ -773,12 +774,14 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
         }
     }
 
-    ret = qemu_vfio_pci_init_irq(s->vfio, &s->irq_notifier,
+    ret = qemu_vfio_pci_init_irq(s->vfio,
+                                 &s->queues[QUEUE_INDEX_ADMIN]->irq_notifier,
                                  VFIO_PCI_MSIX_IRQ_INDEX, errp);
     if (ret) {
         goto out;
     }
-    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+    aio_set_event_notifier(aio_context,
+                           &s->queues[QUEUE_INDEX_ADMIN]->irq_notifier,
                            false, nvme_handle_event, nvme_poll_cb);
 
     nvme_identify(bs, namespace, &local_err);
@@ -789,7 +792,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     }
 
     /* Set up command queues. */
-    if (!nvme_add_io_queue(bs, errp)) {
+    if (!nvme_add_io_queue(bs, aio_context, errp)) {
         ret = -EIO;
     }
 out:
@@ -858,12 +861,14 @@ static void nvme_close(BlockDriverState *bs)
     BDRVNVMeState *s = bs->opaque;
 
     for (i = 0; i < s->nr_queues; ++i) {
-        nvme_free_queue_pair(s->queues[i]);
+        NVMeQueuePair *q = s->queues[i];
+
+        aio_set_event_notifier(q->aio_context,
+                               &q->irq_notifier, false, NULL, NULL);
+        event_notifier_cleanup(&q->irq_notifier);
+        nvme_free_queue_pair(q);
     }
     g_free(s->queues);
-    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
-                           false, NULL, NULL);
-    event_notifier_cleanup(&s->irq_notifier);
     qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
     qemu_vfio_close(s->vfio);
 
@@ -1075,7 +1080,7 @@ static coroutine_fn int nvme_co_prw_aligned(BlockDriverState *bs,
         .cdw12 = cpu_to_le32(cdw12),
     };
     NVMeCoData data = {
-        .ctx = bdrv_get_aio_context(bs),
+        .ctx = ioq->aio_context,
         .ret = -EINPROGRESS,
     };
 
@@ -1184,7 +1189,7 @@ static coroutine_fn int nvme_co_flush(BlockDriverState *bs)
         .nsid = cpu_to_le32(s->nsid),
     };
     NVMeCoData data = {
-        .ctx = bdrv_get_aio_context(bs),
+        .ctx = ioq->aio_context,
         .ret = -EINPROGRESS,
     };
 
@@ -1225,7 +1230,7 @@ static coroutine_fn int nvme_co_pwrite_zeroes(BlockDriverState *bs,
     };
 
     NVMeCoData data = {
-        .ctx = bdrv_get_aio_context(bs),
+        .ctx = ioq->aio_context,
         .ret = -EINPROGRESS,
     };
 
@@ -1275,7 +1280,7 @@ static int coroutine_fn nvme_co_pdiscard(BlockDriverState *bs,
     };
 
     NVMeCoData data = {
-        .ctx = bdrv_get_aio_context(bs),
+        .ctx = ioq->aio_context,
         .ret = -EINPROGRESS,
     };
 
@@ -1368,10 +1373,10 @@ static void nvme_detach_aio_context(BlockDriverState *bs)
 
         qemu_bh_delete(q->completion_bh);
         q->completion_bh = NULL;
-    }
 
-    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
-                           false, NULL, NULL);
+        aio_set_event_notifier(bdrv_get_aio_context(bs), &q->irq_notifier,
+                               false, NULL, NULL);
+    }
 }
 
 static void nvme_attach_aio_context(BlockDriverState *bs,
@@ -1379,13 +1384,11 @@ static void nvme_attach_aio_context(BlockDriverState *bs,
 {
     BDRVNVMeState *s = bs->opaque;
 
-    s->aio_context = new_context;
-    aio_set_event_notifier(new_context, &s->irq_notifier,
-                           false, nvme_handle_event, nvme_poll_cb);
-
     for (int i = 0; i < s->nr_queues; i++) {
         NVMeQueuePair *q = s->queues[i];
 
+        aio_set_event_notifier(new_context, &q->irq_notifier,
+                               false, nvme_handle_event, nvme_poll_cb);
         q->completion_bh =
             aio_bh_new(new_context, nvme_process_completion_bh, q);
     }
-- 
2.21.3