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authorstephen hemminger <stephen@networkplumber.org>2017-02-27 21:26:48 +0300
committerDavid S. Miller <davem@davemloft.net>2017-03-07 04:13:13 +0300
commitf3dd3f4797652c311df9c074436d420f1ad3566e (patch)
tree029e7602f0594a5b805828c33c40448cdb58623f /include/linux/hyperv.h
parent50698d80f8bb1db989b7b9fa433f588fade5e382 (diff)
downloadlinux-f3dd3f4797652c311df9c074436d420f1ad3566e.tar.xz
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 <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/hyperv.h')
-rw-r--r--include/linux/hyperv.h96
1 files changed, 30 insertions, 66 deletions
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 62bbf3c1aa4a..36162485d663 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
-static inline struct vmpacket_descriptor *
-get_next_pkt_raw(struct vmbus_channel *channel)
+/* Get data payload associated with descriptor */
+static inline void *hv_pkt_data(const struct vmpacket_descriptor *desc)
{
- 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);
-
- if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))
- return NULL;
-
- return ring_buffer + priv_read_loc;
+ return (void *)((unsigned long)desc + (desc->offset8 << 3));
}
-/*
- * 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)
+/* Get data size associated with descriptor */
+static inline u32 hv_pkt_datalen(const 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;
+ 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);
+
/*
- * 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();
+ * Get next packet descriptor from iterator
+ * If at end of list, return NULL and update host.
*/
-static inline void commit_rd_index(struct vmbus_channel *channel)
+static inline struct vmpacket_descriptor *
+hv_pkt_iter_next(struct vmbus_channel *channel,
+ const struct vmpacket_descriptor *pkt)
{
- 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;
+ struct vmpacket_descriptor *nxt;
+
+ nxt = __hv_pkt_iter_next(channel, pkt);
+ if (!nxt)
+ hv_pkt_iter_close(channel);
- hv_signal_on_read(channel);
+ return nxt;
}
+#define foreach_vmbus_pkt(pkt, channel) \
+ for (pkt = hv_pkt_iter_first(channel); pkt; \
+ pkt = hv_pkt_iter_next(channel, pkt))
#endif /* _HYPERV_H */