On Mon, Feb 04, 2019 at 02:17:50PM -0700, Jason Gunthorpe wrote:
> +/*
> + * xarray has this annoying behavior where it won't iterate over NULL values
> + * stored in allocated arrays. So we need our own iterator to see all values
> + * stored in the array. This does the same thing as xa_for_each except that it
> + * also returns NULL valued entries if the array is allocating. Simplified to
> + * only work on simple xarrays.
> + */
> +static void *xan_find(struct xarray *xa, unsigned long *indexp,
> + unsigned long max, xa_mark_t filter)
> +{
> + XA_STATE(xas, xa, *indexp);
> + void *entry;
> +
> + rcu_read_lock();
> + do {
> + if ((__force unsigned int)filter < XA_MAX_MARKS)
> + entry = xas_find_marked(&xas, max, filter);
> + else
> + entry = xas_find(&xas, max);
> + if (xa_is_zero(entry) && !xas_get_mark(&xas, XA_FREE_MARK))
> + break;
> + } while (xas_retry(&xas, entry));
> + rcu_read_unlock();
> +
> + if (entry) {
> + *indexp = xas.xa_index;
> + if (xa_is_zero(entry))
> + return NULL;
> + return entry;
> + }
> + return ERR_PTR(-ENOENT);
> +}
> +#define xan_for_each(xa, index, entry, filter) \
> + for (index = 0, entry = xan_find(xa, &(index), ULONG_MAX, filter); \
> + !IS_ERR(entry); \
> + (index)++, entry = xan_find(xa, &(index), ULONG_MAX, filter))
We can't do this in the generic XArray code because ERR_PTR(-ENOENT) might
overlap with an XArray value entry.
Now, what you can do is iterate using xas_for_each(). That will return the
zeroed entries.
XA_STATE(xas, &dev->client_data, 0);
...
rcu_read_lock();
xas_for_each_marked(&xas, client_data, ULONG_MAX,
CLIENT_DATA_REGISTERED) {
struct ib_client *client = xa_load(&clients, xas.xa_index);
...
I'm not familiar enough with your code to figure out where you'd want
to rcu_read_unlock() :-)
