Re: [PATCH v5 15/15] block/nvme: Use an array of EventNotifier

[Stefano Garzarella <sgarzare@redhat.com>]

On Thu, Aug 20, 2020 at 06:59:01PM +0200, Philippe Mathieu-Daudé wrote:
> 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).
> 
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> 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,

Maybe we can use '&s->irq_notifier[MSIX_SHARED_IRQ_IDX]' to match the other
changes.

>                                   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
> 
>