Subject: Re: linux-next: build failure after merge of the xarray tree

From: Jason Gunthorpe <[email-masked]>
Date: Mon, 11 Mar 2019 12:13:54 +0000

On Sun, Mar 10, 2019 at 07:44:34PM -0700, Matthew Wilcox wrote:
> On Thu, Feb 21, 2019 at 12:34:42PM +0000, Leon Romanovsky wrote:
> > On Thu, Feb 21, 2019 at 05:13:32PM +1100, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > After merging the xarray tree, today's linux-next build (powerpc
> > > ppc64_defconfig) failed like this:
> 
> [API change]
> 
> So I ended up being really busy last week and not having time to send
> my merge request for XArray yet.  I'm going to send a request this week;
> Leon and Jason, how does this merge resolution look?
> 
> Compile tested only.
> 
> diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
> index a9f29156e486..8a93c0c95953 100644
> +++ b/drivers/infiniband/core/device.c
> @@ -668,19 +668,10 @@ static int assign_name(struct ib_device *device, const char *name)
>  	}
>  	strlcpy(device->name, dev_name(&device->dev), IB_DEVICE_NAME_MAX);
>  
> -	/* Cyclically allocate a user visible ID for the device */
> -	device->index = last_id;
> -	ret = xa_alloc(&devices, &device->index, INT_MAX, device, GFP_KERNEL);
> -	if (ret == -ENOSPC) {
> -		device->index = 0;
> -		ret = xa_alloc(&devices, &device->index, INT_MAX, device,
> -			       GFP_KERNEL);
> -	}
> -	if (ret)
> -		goto out;
> -	last_id = device->index + 1;
> -
> -	ret = 0;
> +	ret = xa_alloc_cyclic(&devices, &device->index, device, xa_limit_31b,
> +			&last_id, GFP_KERNEL);
> +	if (ret > 0)
> +		ret = 0;
>  
>  out:
>  	up_write(&devices_rwsem);
> @@ -1059,14 +1050,14 @@ static int assign_client_id(struct ib_client *client)
>  	 * to get the LIFO order. The extra linked list can go away if xarray
>  	 * learns to reverse iterate.
>  	 */
> -	if (list_empty(&client_list))
> +	if (list_empty(&client_list)) {
>  		client->client_id = 0;
> -	else
> -		client->client_id =
> -			list_last_entry(&client_list, struct ib_client, list)
> -				->client_id;
> -	ret = xa_alloc(&clients, &client->client_id, INT_MAX, client,
> -		       GFP_KERNEL);
> +	} else {
> +		struct ib_client *last = list_last_entry(&client_list,
> +				struct ib_client, list);
> +		client->client_id = last->client_id + 1;

blank line after locals, but other wise these all looks fine.. 

Should have started out with the xa_insert version above..

Thanks,
Jason