Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bb08d431 authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Greg Kroah-Hartman
Browse files

Drivers: hv: ring_buffer: count on wrap around mappings in get_next_pkt_raw() 



With wrap around mappings in place we can always provide drivers with
direct links to packets on the ring buffer, even when they wrap around.
Do the required updates to get_next_pkt_raw()/put_pkt_raw()

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Tested-by: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f24f0b49

include/linux/hyperv.h

+11 −21
Original line number Original line Diff line number Diff line
@@ -1469,31 +1469,23 @@ static inline struct vmpacket_descriptor * 
get_next_pkt_raw(struct vmbus_channel *channel)

get_next_pkt_raw(struct vmbus_channel *channel)

{

{

	struct hv_ring_buffer_info *ring_info = &channel->inbound;

	struct hv_ring_buffer_info *ring_info = &channel->inbound;

	u32 read_loc = ring_info->priv_read_index;

	u32 priv_read_loc = ring_info->priv_read_index;

	void *ring_buffer = hv_get_ring_buffer(ring_info);

	void *ring_buffer = hv_get_ring_buffer(ring_info);

	struct vmpacket_descriptor *cur_desc;

	u32 packetlen;

	u32 dsize = ring_info->ring_datasize;

	u32 dsize = ring_info->ring_datasize;

	u32 delta = read_loc - ring_info->ring_buffer->read_index;

	/*

	 * 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);

	u32 bytes_avail_toread = (hv_get_bytes_to_read(ring_info) - delta);





	if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))

	if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))

		return NULL;

		return NULL;





	if ((read_loc + sizeof(*cur_desc)) > dsize)

	return ring_buffer + priv_read_loc;

		return NULL;



	cur_desc = ring_buffer + read_loc;

	packetlen = cur_desc->len8 << 3;



	/*

	 * If the packet under consideration is wrapping around,

	 * return failure.

	 */

	if ((read_loc + packetlen + VMBUS_PKT_TRAILER) > (dsize - 1))

		return NULL;



	return cur_desc;

}

}





/*

/*
@@ -1505,16 +1497,14 @@ static inline void put_pkt_raw(struct vmbus_channel *channel, 
				struct vmpacket_descriptor *desc)

				struct vmpacket_descriptor *desc)

{

{

	struct hv_ring_buffer_info *ring_info = &channel->inbound;

	struct hv_ring_buffer_info *ring_info = &channel->inbound;

	u32 read_loc = ring_info->priv_read_index;

	u32 packetlen = desc->len8 << 3;

	u32 packetlen = desc->len8 << 3;

	u32 dsize = ring_info->ring_datasize;

	u32 dsize = ring_info->ring_datasize;





	if ((read_loc + packetlen + VMBUS_PKT_TRAILER) > dsize)

		BUG();

	/*

	/*

	 * Include the packet trailer.

	 * Include the packet trailer.

	 */

	 */

	ring_info->priv_read_index += packetlen + VMBUS_PKT_TRAILER;

	ring_info->priv_read_index += packetlen + VMBUS_PKT_TRAILER;

	ring_info->priv_read_index %= dsize;

}

}





/*

/*