By directly using find_first_bit() and find_next_bit from the
"bitops.h" API to iterate over the bitmap, we can remove the
bitmap[] variable-length array copy on the stack and the complex
manual bit testing/clearing logic.
Suggested-by: Stefan Hajnoczi <stefa...@redhat.com>
Suggested-by: Richard Henderson <richard.hender...@linaro.org>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
hw/block/dataplane/virtio-blk.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index e9050c8987e..a31fa94ca33 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -60,24 +60,14 @@ static void notify_guest_bh(void *opaque)
{
VirtIOBlockDataPlane *s = opaque;
unsigned nvqs = s->conf->num_queues;
- unsigned long bitmap[BITS_TO_LONGS(nvqs)];
- unsigned j;
- memcpy(bitmap, s->batch_notify_vqs, sizeof(bitmap));
- memset(s->batch_notify_vqs, 0, sizeof(bitmap));
+ for (unsigned long i = find_first_bit(s->batch_notify_vqs, nvqs);
+ i < nvqs; i = find_next_bit(s->batch_notify_vqs, nvqs, i)) {
+ VirtQueue *vq = virtio_get_queue(s->vdev, i);
- for (j = 0; j < nvqs; j += BITS_PER_LONG) {
- unsigned long bits = bitmap[j / BITS_PER_LONG];
-
- while (bits != 0) {
- unsigned i = j + ctzl(bits);
- VirtQueue *vq = virtio_get_queue(s->vdev, i);
-
- virtio_notify_irqfd(s->vdev, vq);
-
- bits &= bits - 1; /* clear right-most bit */
- }
+ virtio_notify_irqfd(s->vdev, vq);
}
+ bitmap_clear(s->batch_notify_vqs, 0, nvqs);
}
/* Context: QEMU global mutex held */
--
2.26.3
