vmbus: introduce in-place packet iterator
This is mostly just a refactoring of previous functions
(get_pkt_next_raw, put_pkt_raw and commit_rd_index) to make it easier
to use for other drivers and NAPI.
Signed-off-by: Stephen Hemminger <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 62bbf3c..3616248 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1504,14 +1504,6 @@ static inline void hv_signal_on_read(struct vmbus_channel *channel)
return;
}
-static inline void
-init_cached_read_index(struct vmbus_channel *channel)
-{
- struct hv_ring_buffer_info *rbi = &channel->inbound;
-
- rbi->cached_read_index = rbi->ring_buffer->read_index;
-}
-
/*
* Mask off host interrupt callback notifications
*/
@@ -1545,76 +1537,48 @@ static inline u32 hv_end_read(struct hv_ring_buffer_info *rbi)
/*
* An API to support in-place processing of incoming VMBUS packets.
*/
-#define VMBUS_PKT_TRAILER 8
+/* Get data payload associated with descriptor */
+static inline void *hv_pkt_data(const struct vmpacket_descriptor *desc)
+{
+ return (void *)((unsigned long)desc + (desc->offset8 << 3));
+}
+
+/* Get data size associated with descriptor */
+static inline u32 hv_pkt_datalen(const struct vmpacket_descriptor *desc)
+{
+ return (desc->len8 << 3) - (desc->offset8 << 3);
+}
+
+
+struct vmpacket_descriptor *
+hv_pkt_iter_first(struct vmbus_channel *channel);
+
+struct vmpacket_descriptor *
+__hv_pkt_iter_next(struct vmbus_channel *channel,
+ const struct vmpacket_descriptor *pkt);
+
+void hv_pkt_iter_close(struct vmbus_channel *channel);
+
+/*
+ * Get next packet descriptor from iterator
+ * If at end of list, return NULL and update host.
+ */
static inline struct vmpacket_descriptor *
-get_next_pkt_raw(struct vmbus_channel *channel)
+hv_pkt_iter_next(struct vmbus_channel *channel,
+ const struct vmpacket_descriptor *pkt)
{
- struct hv_ring_buffer_info *ring_info = &channel->inbound;
- u32 priv_read_loc = ring_info->priv_read_index;
- void *ring_buffer = hv_get_ring_buffer(ring_info);
- u32 dsize = ring_info->ring_datasize;
- /*
- * delta is the difference between what is available to read and
- * what was already consumed in place. We commit read index after
- * the whole batch is processed.
- */
- u32 delta = priv_read_loc >= ring_info->ring_buffer->read_index ?
- priv_read_loc - ring_info->ring_buffer->read_index :
- (dsize - ring_info->ring_buffer->read_index) + priv_read_loc;
- u32 bytes_avail_toread = (hv_get_bytes_to_read(ring_info) - delta);
+ struct vmpacket_descriptor *nxt;
- if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))
- return NULL;
+ nxt = __hv_pkt_iter_next(channel, pkt);
+ if (!nxt)
+ hv_pkt_iter_close(channel);
- return ring_buffer + priv_read_loc;
+ return nxt;
}
-/*
- * A helper function to step through packets "in-place"
- * This API is to be called after each successful call
- * get_next_pkt_raw().
- */
-static inline void put_pkt_raw(struct vmbus_channel *channel,
- struct vmpacket_descriptor *desc)
-{
- struct hv_ring_buffer_info *ring_info = &channel->inbound;
- u32 packetlen = desc->len8 << 3;
- u32 dsize = ring_info->ring_datasize;
-
- /*
- * Include the packet trailer.
- */
- ring_info->priv_read_index += packetlen + VMBUS_PKT_TRAILER;
- ring_info->priv_read_index %= dsize;
-}
-
-/*
- * This call commits the read index and potentially signals the host.
- * Here is the pattern for using the "in-place" consumption APIs:
- *
- * init_cached_read_index();
- *
- * while (get_next_pkt_raw() {
- * process the packet "in-place";
- * put_pkt_raw();
- * }
- * if (packets processed in place)
- * commit_rd_index();
- */
-static inline void commit_rd_index(struct vmbus_channel *channel)
-{
- struct hv_ring_buffer_info *ring_info = &channel->inbound;
- /*
- * Make sure all reads are done before we update the read index since
- * the writer may start writing to the read area once the read index
- * is updated.
- */
- virt_rmb();
- ring_info->ring_buffer->read_index = ring_info->priv_read_index;
-
- hv_signal_on_read(channel);
-}
-
+#define foreach_vmbus_pkt(pkt, channel) \
+ for (pkt = hv_pkt_iter_first(channel); pkt; \
+ pkt = hv_pkt_iter_next(channel, pkt))
#endif /* _HYPERV_H */
