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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>
This commit is contained in:
stephen hemminger
David S. Miller
parent
50698d80f8
commit
f3dd3f4797
@ -32,6 +32,8 @@
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#include "hyperv_vmbus.h"
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#define VMBUS_PKT_TRAILER 8
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/*
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* When we write to the ring buffer, check if the host needs to
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* be signaled. Here is the details of this protocol:
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@ -336,6 +338,12 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
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return 0;
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}
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static inline void
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init_cached_read_index(struct hv_ring_buffer_info *rbi)
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{
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rbi->cached_read_index = rbi->ring_buffer->read_index;
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}
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int hv_ringbuffer_read(struct vmbus_channel *channel,
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void *buffer, u32 buflen, u32 *buffer_actual_len,
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u64 *requestid, bool raw)
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@ -366,7 +374,8 @@ int hv_ringbuffer_read(struct vmbus_channel *channel,
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return ret;
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}
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init_cached_read_index(channel);
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init_cached_read_index(inring_info);
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next_read_location = hv_get_next_read_location(inring_info);
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next_read_location = hv_copyfrom_ringbuffer(inring_info, &desc,
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sizeof(desc),
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@ -410,3 +419,86 @@ int hv_ringbuffer_read(struct vmbus_channel *channel,
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return ret;
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}
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/*
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* Determine number of bytes available in ring buffer after
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* the current iterator (priv_read_index) location.
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*
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* This is similar to hv_get_bytes_to_read but with private
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* read index instead.
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*/
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static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
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{
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u32 priv_read_loc = rbi->priv_read_index;
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u32 write_loc = READ_ONCE(rbi->ring_buffer->write_index);
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if (write_loc >= priv_read_loc)
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return write_loc - priv_read_loc;
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else
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return (rbi->ring_datasize - priv_read_loc) + write_loc;
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}
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/*
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* Get first vmbus packet from ring buffer after read_index
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*
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* If ring buffer is empty, returns NULL and no other action needed.
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*/
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struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel)
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{
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struct hv_ring_buffer_info *rbi = &channel->inbound;
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/* set state for later hv_signal_on_read() */
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init_cached_read_index(rbi);
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if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))
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return NULL;
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return hv_get_ring_buffer(rbi) + rbi->priv_read_index;
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}
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EXPORT_SYMBOL_GPL(hv_pkt_iter_first);
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/*
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* Get next vmbus packet from ring buffer.
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*
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* Advances the current location (priv_read_index) and checks for more
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* data. If the end of the ring buffer is reached, then return NULL.
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*/
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struct vmpacket_descriptor *
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__hv_pkt_iter_next(struct vmbus_channel *channel,
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const struct vmpacket_descriptor *desc)
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{
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struct hv_ring_buffer_info *rbi = &channel->inbound;
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u32 packetlen = desc->len8 << 3;
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u32 dsize = rbi->ring_datasize;
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/* bump offset to next potential packet */
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rbi->priv_read_index += packetlen + VMBUS_PKT_TRAILER;
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if (rbi->priv_read_index >= dsize)
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rbi->priv_read_index -= dsize;
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/* more data? */
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if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))
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return NULL;
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else
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return hv_get_ring_buffer(rbi) + rbi->priv_read_index;
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}
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EXPORT_SYMBOL_GPL(__hv_pkt_iter_next);
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/*
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* Update host ring buffer after iterating over packets.
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*/
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void hv_pkt_iter_close(struct vmbus_channel *channel)
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{
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struct hv_ring_buffer_info *rbi = &channel->inbound;
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/*
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* Make sure all reads are done before we update the read index since
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* the writer may start writing to the read area once the read index
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* is updated.
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*/
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virt_rmb();
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rbi->ring_buffer->read_index = rbi->priv_read_index;
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hv_signal_on_read(channel);
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}
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EXPORT_SYMBOL_GPL(hv_pkt_iter_close);
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@ -647,14 +647,11 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
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static void netvsc_send_completion(struct netvsc_device *net_device,
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struct vmbus_channel *incoming_channel,
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struct hv_device *device,
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struct vmpacket_descriptor *packet)
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const struct vmpacket_descriptor *desc)
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{
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struct nvsp_message *nvsp_packet;
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struct nvsp_message *nvsp_packet = hv_pkt_data(desc);
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struct net_device *ndev = hv_get_drvdata(device);
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nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
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(packet->offset8 << 3));
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switch (nvsp_packet->hdr.msg_type) {
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case NVSP_MSG_TYPE_INIT_COMPLETE:
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case NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE:
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@ -668,7 +665,7 @@ static void netvsc_send_completion(struct netvsc_device *net_device,
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case NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE:
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netvsc_send_tx_complete(net_device, incoming_channel,
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device, packet);
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device, desc);
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break;
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default:
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@ -1071,9 +1068,11 @@ static void netvsc_receive(struct net_device *ndev,
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struct net_device_context *net_device_ctx,
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struct hv_device *device,
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struct vmbus_channel *channel,
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struct vmtransfer_page_packet_header *vmxferpage_packet,
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const struct vmpacket_descriptor *desc,
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struct nvsp_message *nvsp)
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{
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const struct vmtransfer_page_packet_header *vmxferpage_packet
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= container_of(desc, const struct vmtransfer_page_packet_header, d);
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char *recv_buf = net_device->recv_buf;
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u32 status = NVSP_STAT_SUCCESS;
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int i;
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@ -1185,12 +1184,10 @@ static void netvsc_process_raw_pkt(struct hv_device *device,
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struct netvsc_device *net_device,
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struct net_device *ndev,
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u64 request_id,
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struct vmpacket_descriptor *desc)
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const struct vmpacket_descriptor *desc)
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{
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struct net_device_context *net_device_ctx = netdev_priv(ndev);
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struct nvsp_message *nvmsg
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= (struct nvsp_message *)((unsigned long)desc
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+ (desc->offset8 << 3));
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struct nvsp_message *nvmsg = hv_pkt_data(desc);
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switch (desc->type) {
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case VM_PKT_COMP:
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@ -1199,9 +1196,7 @@ static void netvsc_process_raw_pkt(struct hv_device *device,
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case VM_PKT_DATA_USING_XFER_PAGES:
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netvsc_receive(ndev, net_device, net_device_ctx,
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device, channel,
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(struct vmtransfer_page_packet_header *)desc,
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nvmsg);
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device, channel, desc, nvmsg);
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break;
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case VM_PKT_DATA_INBAND:
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@ -1223,7 +1218,6 @@ void netvsc_channel_cb(void *context)
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struct netvsc_device *net_device;
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struct vmpacket_descriptor *desc;
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struct net_device *ndev;
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bool need_to_commit = false;
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if (channel->primary_channel != NULL)
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device = channel->primary_channel->device_obj;
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@ -1239,20 +1233,12 @@ void netvsc_channel_cb(void *context)
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netvsc_channel_idle(net_device, q_idx))
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return;
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/* commit_rd_index() -> hv_signal_on_read() needs this. */
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init_cached_read_index(channel);
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while ((desc = get_next_pkt_raw(channel)) != NULL) {
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foreach_vmbus_pkt(desc, channel) {
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netvsc_process_raw_pkt(device, channel, net_device,
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ndev, desc->trans_id, desc);
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put_pkt_raw(channel, desc);
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need_to_commit = true;
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}
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if (need_to_commit)
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commit_rd_index(channel);
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netvsc_chk_recv_comp(net_device, channel, q_idx);
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}
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@ -1504,14 +1504,6 @@ static inline void hv_signal_on_read(struct vmbus_channel *channel)
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return;
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}
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static inline void
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init_cached_read_index(struct vmbus_channel *channel)
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{
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struct hv_ring_buffer_info *rbi = &channel->inbound;
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rbi->cached_read_index = rbi->ring_buffer->read_index;
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}
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/*
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* Mask off host interrupt callback notifications
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*/
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@ -1545,76 +1537,48 @@ static inline u32 hv_end_read(struct hv_ring_buffer_info *rbi)
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/*
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* An API to support in-place processing of incoming VMBUS packets.
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*/
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#define VMBUS_PKT_TRAILER 8
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/* Get data payload associated with descriptor */
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static inline void *hv_pkt_data(const struct vmpacket_descriptor *desc)
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{
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return (void *)((unsigned long)desc + (desc->offset8 << 3));
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}
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/* Get data size associated with descriptor */
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static inline u32 hv_pkt_datalen(const struct vmpacket_descriptor *desc)
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{
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return (desc->len8 << 3) - (desc->offset8 << 3);
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}
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struct vmpacket_descriptor *
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hv_pkt_iter_first(struct vmbus_channel *channel);
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struct vmpacket_descriptor *
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__hv_pkt_iter_next(struct vmbus_channel *channel,
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const struct vmpacket_descriptor *pkt);
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void hv_pkt_iter_close(struct vmbus_channel *channel);
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/*
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* Get next packet descriptor from iterator
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* If at end of list, return NULL and update host.
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*/
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static inline struct vmpacket_descriptor *
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get_next_pkt_raw(struct vmbus_channel *channel)
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hv_pkt_iter_next(struct vmbus_channel *channel,
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const struct vmpacket_descriptor *pkt)
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{
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struct hv_ring_buffer_info *ring_info = &channel->inbound;
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u32 priv_read_loc = ring_info->priv_read_index;
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void *ring_buffer = hv_get_ring_buffer(ring_info);
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u32 dsize = ring_info->ring_datasize;
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/*
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* delta is the difference between what is available to read and
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* what was already consumed in place. We commit read index after
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* the whole batch is processed.
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*/
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u32 delta = priv_read_loc >= ring_info->ring_buffer->read_index ?
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priv_read_loc - ring_info->ring_buffer->read_index :
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(dsize - ring_info->ring_buffer->read_index) + priv_read_loc;
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u32 bytes_avail_toread = (hv_get_bytes_to_read(ring_info) - delta);
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struct vmpacket_descriptor *nxt;
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if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))
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return NULL;
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nxt = __hv_pkt_iter_next(channel, pkt);
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if (!nxt)
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hv_pkt_iter_close(channel);
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return ring_buffer + priv_read_loc;
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}
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/*
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* A helper function to step through packets "in-place"
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* This API is to be called after each successful call
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* get_next_pkt_raw().
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*/
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static inline void put_pkt_raw(struct vmbus_channel *channel,
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struct vmpacket_descriptor *desc)
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{
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struct hv_ring_buffer_info *ring_info = &channel->inbound;
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u32 packetlen = desc->len8 << 3;
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u32 dsize = ring_info->ring_datasize;
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/*
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* Include the packet trailer.
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*/
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ring_info->priv_read_index += packetlen + VMBUS_PKT_TRAILER;
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ring_info->priv_read_index %= dsize;
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}
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/*
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* This call commits the read index and potentially signals the host.
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* Here is the pattern for using the "in-place" consumption APIs:
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*
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* init_cached_read_index();
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*
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* while (get_next_pkt_raw() {
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* process the packet "in-place";
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* put_pkt_raw();
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* }
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* if (packets processed in place)
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* commit_rd_index();
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*/
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static inline void commit_rd_index(struct vmbus_channel *channel)
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{
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struct hv_ring_buffer_info *ring_info = &channel->inbound;
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/*
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* Make sure all reads are done before we update the read index since
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* the writer may start writing to the read area once the read index
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* is updated.
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*/
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virt_rmb();
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ring_info->ring_buffer->read_index = ring_info->priv_read_index;
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hv_signal_on_read(channel);
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return nxt;
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}
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#define foreach_vmbus_pkt(pkt, channel) \
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for (pkt = hv_pkt_iter_first(channel); pkt; \
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pkt = hv_pkt_iter_next(channel, pkt))
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#endif /* _HYPERV_H */
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