[RFC PATCH 6/6] Drivers: hv: vmbus: Refactor the ring-buffer iterator functions

From: Andrea Parri (Microsoft)
Date: Wed Apr 13 2022 - 16:48:34 EST


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: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
---
drivers/hv/ring_buffer.c | 11 +++++------
include/linux/hyperv.h | 35 ++++-------------------------------
2 files changed, 9 insertions(+), 37 deletions(-)

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 3d215d9dec433..c9357dae2a2c8 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -421,7 +421,7 @@ 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);
@@ -459,7 +459,8 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
/*
* Get first vmbus packet without copying it out of the ring buffer
*/
-struct vmpacket_descriptor *hv_pkt_iter_first_raw(struct vmbus_channel *channel)
+static struct vmpacket_descriptor *
+hv_pkt_iter_first_raw(struct vmbus_channel *channel)
{
struct hv_ring_buffer_info *rbi = &channel->inbound;

@@ -470,7 +471,6 @@ struct vmpacket_descriptor *hv_pkt_iter_first_raw(struct vmbus_channel *channel)

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
@@ -534,8 +534,7 @@ 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;
@@ -548,7 +547,7 @@ __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);

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 1112c5cf894e6..370adc9971d3e 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1673,55 +1673,28 @@ 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))
--
2.25.1