[RFC PATCH v4 1/5] block/nvme: Use an array of EventNotifier

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

In preparation of using multiple IRQ (thus multiple eventfds)
make BDRVNVMeState::irq_notifier an array (for now of a single
element, the admin queue notifier).

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 block/nvme.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/block/nvme.c b/block/nvme.c
index a61e86a83eb..fe8a40b7ede 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -106,6 +106,12 @@ QEMU_BUILD_BUG_ON(offsetof(NVMeRegs, doorbells) != 0x1000);
 #define INDEX_ADMIN     0
 #define INDEX_IO(n)     (1 + n)
 
+/* This driver shares a single MSIX IRQ for the admin and I/O queues */
+enum {
+    MSIX_SHARED_IRQ_IDX = 0,
+    MSIX_IRQ_COUNT = 1
+};
+
 struct BDRVNVMeState {
     AioContext *aio_context;
     QEMUVFIOState *vfio;
@@ -120,7 +126,7 @@ struct BDRVNVMeState {
     /* How many uint32_t elements does each doorbell entry take. */
     size_t doorbell_scale;
     bool write_cache_supported;
-    EventNotifier irq_notifier;
+    EventNotifier irq_notifier[MSIX_IRQ_COUNT];
 
     uint64_t nsze; /* Namespace size reported by identify command */
     int nsid;      /* The namespace id to read/write data. */
@@ -631,7 +637,8 @@ static bool nvme_poll_queues(BDRVNVMeState *s)
 
 static void nvme_handle_event(EventNotifier *n)
 {
-    BDRVNVMeState *s = container_of(n, BDRVNVMeState, irq_notifier);
+    BDRVNVMeState *s = container_of(n, BDRVNVMeState,
+                                    irq_notifier[MSIX_SHARED_IRQ_IDX]);
 
     trace_nvme_handle_event(s);
     event_notifier_test_and_clear(n);
@@ -683,7 +690,8 @@ out_error:
 static bool nvme_poll_cb(void *opaque)
 {
     EventNotifier *e = opaque;
-    BDRVNVMeState *s = container_of(e, BDRVNVMeState, irq_notifier);
+    BDRVNVMeState *s = container_of(e, BDRVNVMeState,
+                                    irq_notifier[MSIX_SHARED_IRQ_IDX]);
 
     trace_nvme_poll_cb(s);
     return nvme_poll_queues(s);
@@ -705,7 +713,7 @@ static int nvme_init(BlockDriverState *bs, const char *device, int namespace,
     s->device = g_strdup(device);
     s->nsid = namespace;
     s->aio_context = bdrv_get_aio_context(bs);
-    ret = event_notifier_init(&s->irq_notifier, 0);
+    ret = event_notifier_init(&s->irq_notifier[MSIX_SHARED_IRQ_IDX], 0);
     if (ret) {
         error_setg(errp, "Failed to init event notifier");
         return ret;
@@ -784,12 +792,13 @@ 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->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(bdrv_get_aio_context(bs),
+                           &s->irq_notifier[MSIX_SHARED_IRQ_IDX],
                            false, nvme_handle_event, nvme_poll_cb);
 
     nvme_identify(bs, namespace, &local_err);
@@ -872,9 +881,10 @@ static void nvme_close(BlockDriverState *bs)
         nvme_free_queue_pair(s->queues[i]);
     }
     g_free(s->queues);
-    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+    aio_set_event_notifier(bdrv_get_aio_context(bs),
+                           &s->irq_notifier[MSIX_SHARED_IRQ_IDX],
                            false, NULL, NULL);
-    event_notifier_cleanup(&s->irq_notifier);
+    event_notifier_cleanup(&s->irq_notifier[MSIX_SHARED_IRQ_IDX]);
     qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
     qemu_vfio_close(s->vfio);
 
@@ -1381,7 +1391,8 @@ static void nvme_detach_aio_context(BlockDriverState *bs)
         q->completion_bh = NULL;
     }
 
-    aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
+    aio_set_event_notifier(bdrv_get_aio_context(bs),
+                           &s->irq_notifier[MSIX_SHARED_IRQ_IDX],
                            false, NULL, NULL);
 }
 
@@ -1391,7 +1402,7 @@ 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,
+    aio_set_event_notifier(new_context, &s->irq_notifier[MSIX_SHARED_IRQ_IDX],
                            false, nvme_handle_event, nvme_poll_cb);
 
     for (int i = 0; i < s->nr_queues; i++) {
-- 
2.26.2