From f3dd3f4797652c311df9c074436d420f1ad3566e Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Mon, 27 Feb 2017 10:26:48 -0800 Subject: 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 Signed-off-by: David S. Miller --- include/linux/hyperv.h | 96 ++++++++++++++++---------------------------------- 1 file changed, 30 insertions(+), 66 deletions(-) (limited to 'include/linux/hyperv.h') 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 */ -- cgit v1.2.3