Very much a WIP!
The page backing store should not be removed until all ouststanding
packets are returned. The packets may be inflight, owned by the
driver or sitting in a socket buffer.
This shows how the cleanup routine should check that there are no
pending packets in flight, before cleaning up the buffers.
Signed-off-by: Jonathan Lemon <jonathan.lemon@xxxxxxxxx>
---
io_uring/zctap.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff --git a/io_uring/zctap.c b/io_uring/zctap.c
index 4a551349b600..a1525a0b0245 100644
--- a/io_uring/zctap.c
+++ b/io_uring/zctap.c
@@ -25,6 +25,7 @@ struct ifq_region {
u16 id;
spinlock_t freelist_lock;
+ struct delayed_work release_work;
struct io_zctap_buf *buf;
struct io_zctap_buf *freelist[];
@@ -199,24 +200,38 @@ static void io_zctap_put_page(struct io_zctap_ifq *ifq, struct page *page)
io_zctap_put_buf(ifq, &ifr->buf[pgid]);
}
-static void io_remove_ifq_region(struct ifq_region *ifr)
+static void io_remove_ifq_region_work(struct work_struct *work)
{
- struct io_mapped_ubuf *imu;
- struct page *page;
- int i;
+ struct ifq_region *ifr = container_of(
+ to_delayed_work(work), struct ifq_region, release_work);
+ struct io_zctap_buf *buf;
+ int i, refs;
- imu = ifr->imu;
for (i = 0; i < ifr->nr_pages; i++) {
- page = imu->bvec[i].bv_page;
+ buf = &ifr->buf[i];
+ refs = atomic_read(&buf->refcount) & IO_ZCTAP_KREF_MASK;
+ if (refs) {
+ schedule_delayed_work(&ifr->release_work, HZ);
+ return;
+ }
+ }
- ClearPagePrivate(page);
- set_page_private(page, 0);
+ for (i = 0; i < ifr->nr_pages; i++) {
+ buf = &ifr->buf[i];
+ set_page_private(buf->page, 0);
+ ClearPagePrivate(buf->page);
}
kvfree(ifr->buf);
kvfree(ifr);
}
+static void io_remove_ifq_region(struct ifq_region *ifr)
+{
+ INIT_DELAYED_WORK(&ifr->release_work, io_remove_ifq_region_work);
+ schedule_delayed_work(&ifr->release_work, 0);
+}
+
static inline struct device *
netdev2device(struct net_device *dev)
{
@@ -403,6 +418,8 @@ static struct io_zctap_ifq *io_zctap_ifq_alloc(void)
return &priv->ifq;
}
+/* XXX this seems to be called too late - MM is already torn down? */
+/* need to tear down sockets, then io_uring, then MM */
static void io_zctap_ifq_free(struct io_zctap_ifq *ifq)
{
if (ifq->queue_id != -1)
--
2.30.2
