Commit 1c9de08f authored by Andrea Parri (Microsoft)'s avatar Andrea Parri (Microsoft) Committed by Wei Liu
Browse files

Drivers: hv: vmbus: Refactor the ring-buffer iterator functions 



With no users of hv_pkt_iter_next_raw() and no "external" users of
hv_pkt_iter_first_raw(), the iterator functions can be refactored
and simplified to remove some indirection/code.

Signed-off-by: default avatarAndrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220428145107.7878-6-parri.andrea@gmail.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent da795eb2

drivers/hv/ring_buffer.c

+9 −23
Original line number Diff line number Diff line
@@ -429,7 +429,7 @@ int hv_ringbuffer_read(struct vmbus_channel *channel, 
	memcpy(buffer, (const char *)desc + offset, packetlen);



	/* Advance ring index to next packet descriptor */

	__hv_pkt_iter_next(channel, desc, true);

	__hv_pkt_iter_next(channel, desc);



	/* Notify host of update */

	hv_pkt_iter_close(channel);
@@ -464,22 +464,6 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi) 
		return (rbi->ring_datasize - priv_read_loc) + write_loc;

}



/*

 * Get first vmbus packet without copying it out of the ring buffer

 */

struct vmpacket_descriptor *hv_pkt_iter_first_raw(struct vmbus_channel *channel)

{

	struct hv_ring_buffer_info *rbi = &channel->inbound;



	hv_debug_delay_test(channel, MESSAGE_DELAY);



	if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))

		return NULL;



	return (struct vmpacket_descriptor *)(hv_get_ring_buffer(rbi) + rbi->priv_read_index);

}

EXPORT_SYMBOL_GPL(hv_pkt_iter_first_raw);



/*

 * Get first vmbus packet from ring buffer after read_index

 *
@@ -491,11 +475,14 @@ struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel) 
	struct vmpacket_descriptor *desc, *desc_copy;

	u32 bytes_avail, pkt_len, pkt_offset;



	desc = hv_pkt_iter_first_raw(channel);

	if (!desc)

	hv_debug_delay_test(channel, MESSAGE_DELAY);



	bytes_avail = hv_pkt_iter_avail(rbi);

	if (bytes_avail < sizeof(struct vmpacket_descriptor))

		return NULL;

	bytes_avail = min(rbi->pkt_buffer_size, bytes_avail);



	bytes_avail = min(rbi->pkt_buffer_size, hv_pkt_iter_avail(rbi));

	desc = (struct vmpacket_descriptor *)(hv_get_ring_buffer(rbi) + rbi->priv_read_index);



	/*

	 * Ensure the compiler does not use references to incoming Hyper-V values (which
@@ -542,8 +529,7 @@ EXPORT_SYMBOL_GPL(hv_pkt_iter_first); 
 */

struct vmpacket_descriptor *

__hv_pkt_iter_next(struct vmbus_channel *channel,

		   const struct vmpacket_descriptor *desc,

		   bool copy)

		   const struct vmpacket_descriptor *desc)

{

	struct hv_ring_buffer_info *rbi = &channel->inbound;

	u32 packetlen = desc->len8 << 3;
@@ -556,7 +542,7 @@ __hv_pkt_iter_next(struct vmbus_channel *channel, 
		rbi->priv_read_index -= dsize;



	/* more data? */

	return copy ? hv_pkt_iter_first(channel) : hv_pkt_iter_first_raw(channel);

	return hv_pkt_iter_first(channel);

}

EXPORT_SYMBOL_GPL(__hv_pkt_iter_next);

include/linux/hyperv.h

+4 −31
Original line number Diff line number Diff line
@@ -1706,55 +1706,28 @@ static inline u32 hv_pkt_len(const struct vmpacket_descriptor *desc) 
	return desc->len8 << 3;

}



struct vmpacket_descriptor *

hv_pkt_iter_first_raw(struct vmbus_channel *channel);



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,

		   bool copy);

		   const struct vmpacket_descriptor *pkt);



void hv_pkt_iter_close(struct vmbus_channel *channel);



static inline struct vmpacket_descriptor *

hv_pkt_iter_next_pkt(struct vmbus_channel *channel,

		     const struct vmpacket_descriptor *pkt,

		     bool copy)

hv_pkt_iter_next(struct vmbus_channel *channel,

		 const struct vmpacket_descriptor *pkt)

{

	struct vmpacket_descriptor *nxt;



	nxt = __hv_pkt_iter_next(channel, pkt, copy);

	nxt = __hv_pkt_iter_next(channel, pkt);

	if (!nxt)

		hv_pkt_iter_close(channel);



	return nxt;

}



/*

 * Get next packet descriptor without copying it out of the ring buffer

 * If at end of list, return NULL and update host.

 */

static inline struct vmpacket_descriptor *

hv_pkt_iter_next_raw(struct vmbus_channel *channel,

		     const struct vmpacket_descriptor *pkt)

{

	return hv_pkt_iter_next_pkt(channel, pkt, false);

}



/*

 * Get next packet descriptor from iterator

 * If at end of list, return NULL and update host.

 */

static inline struct vmpacket_descriptor *

hv_pkt_iter_next(struct vmbus_channel *channel,

		 const struct vmpacket_descriptor *pkt)

{

	return hv_pkt_iter_next_pkt(channel, pkt, true);

}



#define foreach_vmbus_pkt(pkt, channel) \

	for (pkt = hv_pkt_iter_first(channel); pkt; \

	    pkt = hv_pkt_iter_next(channel, pkt))