vhost: switch to use vhost_add_used_n() (c49e4e57) · Commits · 戴 / test

drivers/vhost/vhost.c

+12 −42

Original line number	Diff line number	Diff line
		@@ -1332,48 +1332,9 @@ EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
		* want to notify the guest, using eventfd. */
		int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
		{
		struct vring_used_elem __user *used;
		struct vring_used_elem heads = { head, len };

		/* The virtqueue contains a ring of used buffers. Get a pointer to the
		* next entry in that used ring. */
		used = &vq->used->ring[vq->last_used_idx % vq->num];
		if (__put_user(head, &used->id)) {
		vq_err(vq, "Failed to write used id");
		return -EFAULT;
		}
		if (__put_user(len, &used->len)) {
		vq_err(vq, "Failed to write used len");
		return -EFAULT;
		}
		/* Make sure buffer is written before we update index. */
		smp_wmb();
		if (__put_user(vq->last_used_idx + 1, &vq->used->idx)) {
		vq_err(vq, "Failed to increment used idx");
		return -EFAULT;
		}
		if (unlikely(vq->log_used)) {
		/* Make sure data is seen before log. */
		smp_wmb();
		/* Log used ring entry write. */
		log_write(vq->log_base,
		vq->log_addr +
		((void __user )used - (void __user )vq->used),
		sizeof *used);
		/* Log used index update. */
		log_write(vq->log_base,
		vq->log_addr + offsetof(struct vring_used, idx),
		sizeof vq->used->idx);
		if (vq->log_ctx)
		eventfd_signal(vq->log_ctx, 1);
		}
		vq->last_used_idx++;
		/* If the driver never bothers to signal in a very long while,
		* used index might wrap around. If that happens, invalidate
		* signalled_used index we stored. TODO: make sure driver
		* signals at least once in 2^16 and remove this. */
		if (unlikely(vq->last_used_idx == vq->signalled_used))
		vq->signalled_used_valid = false;
		return 0;
		return vhost_add_used_n(vq, &heads, 1);
		}
		EXPORT_SYMBOL_GPL(vhost_add_used);

		@@ -1387,7 +1348,16 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,

		start = vq->last_used_idx % vq->num;
		used = vq->used->ring + start;
		if (__copy_to_user(used, heads, count * sizeof *used)) {
		if (count == 1) {
		if (__put_user(heads[0].id, &used->id)) {
		vq_err(vq, "Failed to write used id");
		return -EFAULT;
		}
		if (__put_user(heads[0].len, &used->len)) {
		vq_err(vq, "Failed to write used len");
		return -EFAULT;
		}
		} else if (__copy_to_user(used, heads, count * sizeof *used)) {
		vq_err(vq, "Failed to write used");
		return -EFAULT;
		}

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