* [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization
@ 2015-12-08 17:07 Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 1/5] Drivers: hv: ring_buffer.c: fix comment style Vitaly Kuznetsov
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: Vitaly Kuznetsov @ 2015-12-08 17:07 UTC (permalink / raw)
To: devel; +Cc: K. Y. Srinivasan, Haiyang Zhang, linux-kernel
Changes since v1: added PATCH 4/5 and 5/5.
1) Fix comment style in ring_buffer.c
2) Remove unneeded smp_read_barrier_depends() from hyperv.h
3) Unify hv_ringbuffer_peek/read() functions
4) Unify vmbus_recvpacket()/vmbus_recvpacket_raw() functions
5) Eliminate hv_ringbuffer_peek().
Vitaly Kuznetsov (5):
Drivers: hv: ring_buffer.c: fix comment style
Drivers: hv: ring_buffer: remove stray smp_read_barrier_depends()
Drivers: hv: ring_buffer: remove code duplication from
hv_ringbuffer_peek/read()
Drivers: hv: remove code duplication between
vmbus_recvpacket()/vmbus_recvpacket_raw()
Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek()
drivers/hv/channel.c | 81 ++++-------------
drivers/hv/hyperv_vmbus.h | 11 +--
drivers/hv/ring_buffer.c | 218 ++++++++++++++--------------------------------
include/linux/hyperv.h | 2 -
4 files changed, 83 insertions(+), 229 deletions(-)
--
2.4.3
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v2 1/5] Drivers: hv: ring_buffer.c: fix comment style
2015-12-08 17:07 [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization Vitaly Kuznetsov
@ 2015-12-08 17:07 ` Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 2/5] Drivers: hv: ring_buffer: remove stray smp_read_barrier_depends() Vitaly Kuznetsov
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Vitaly Kuznetsov @ 2015-12-08 17:07 UTC (permalink / raw)
To: devel; +Cc: K. Y. Srinivasan, Haiyang Zhang, linux-kernel
Convert 6+-string comments repeating function names to normal kernel-style
comments and fix a couple of other comment style issues. No textual or
functional changes intended.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
drivers/hv/ring_buffer.c | 135 +++++++++--------------------------------------
1 file changed, 26 insertions(+), 109 deletions(-)
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 70a1a9a..7bca513 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -112,9 +112,7 @@ static bool hv_need_to_signal_on_read(u32 prev_write_sz,
u32 read_loc = rbi->ring_buffer->read_index;
u32 pending_sz = rbi->ring_buffer->pending_send_sz;
- /*
- * If the other end is not blocked on write don't bother.
- */
+ /* If the other end is not blocked on write don't bother. */
if (pending_sz == 0)
return false;
@@ -128,12 +126,7 @@ static bool hv_need_to_signal_on_read(u32 prev_write_sz,
return false;
}
-/*
- * hv_get_next_write_location()
- *
- * Get the next write location for the specified ring buffer
- *
- */
+/* Get the next write location for the specified ring buffer. */
static inline u32
hv_get_next_write_location(struct hv_ring_buffer_info *ring_info)
{
@@ -142,12 +135,7 @@ hv_get_next_write_location(struct hv_ring_buffer_info *ring_info)
return next;
}
-/*
- * hv_set_next_write_location()
- *
- * Set the next write location for the specified ring buffer
- *
- */
+/* Set the next write location for the specified ring buffer. */
static inline void
hv_set_next_write_location(struct hv_ring_buffer_info *ring_info,
u32 next_write_location)
@@ -155,11 +143,7 @@ hv_set_next_write_location(struct hv_ring_buffer_info *ring_info,
ring_info->ring_buffer->write_index = next_write_location;
}
-/*
- * hv_get_next_read_location()
- *
- * Get the next read location for the specified ring buffer
- */
+/* Get the next read location for the specified ring buffer. */
static inline u32
hv_get_next_read_location(struct hv_ring_buffer_info *ring_info)
{
@@ -169,10 +153,8 @@ hv_get_next_read_location(struct hv_ring_buffer_info *ring_info)
}
/*
- * hv_get_next_readlocation_withoffset()
- *
* Get the next read location + offset for the specified ring buffer.
- * This allows the caller to skip
+ * This allows the caller to skip.
*/
static inline u32
hv_get_next_readlocation_withoffset(struct hv_ring_buffer_info *ring_info,
@@ -186,13 +168,7 @@ hv_get_next_readlocation_withoffset(struct hv_ring_buffer_info *ring_info,
return next;
}
-/*
- *
- * hv_set_next_read_location()
- *
- * Set the next read location for the specified ring buffer
- *
- */
+/* Set the next read location for the specified ring buffer. */
static inline void
hv_set_next_read_location(struct hv_ring_buffer_info *ring_info,
u32 next_read_location)
@@ -201,12 +177,7 @@ hv_set_next_read_location(struct hv_ring_buffer_info *ring_info,
}
-/*
- *
- * hv_get_ring_buffer()
- *
- * Get the start of the ring buffer
- */
+/* Get the start of the ring buffer. */
static inline void *
hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info)
{
@@ -214,25 +185,14 @@ hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info)
}
-/*
- *
- * hv_get_ring_buffersize()
- *
- * Get the size of the ring buffer
- */
+/* Get the size of the ring buffer. */
static inline u32
hv_get_ring_buffersize(struct hv_ring_buffer_info *ring_info)
{
return ring_info->ring_datasize;
}
-/*
- *
- * hv_get_ring_bufferindices()
- *
- * Get the read and write indices as u64 of the specified ring buffer
- *
- */
+/* Get the read and write indices as u64 of the specified ring buffer. */
static inline u64
hv_get_ring_bufferindices(struct hv_ring_buffer_info *ring_info)
{
@@ -240,12 +200,8 @@ hv_get_ring_bufferindices(struct hv_ring_buffer_info *ring_info)
}
/*
- *
- * hv_copyfrom_ringbuffer()
- *
* Helper routine to copy to source from ring buffer.
* Assume there is enough room. Handles wrap-around in src case only!!
- *
*/
static u32 hv_copyfrom_ringbuffer(
struct hv_ring_buffer_info *ring_info,
@@ -277,12 +233,8 @@ static u32 hv_copyfrom_ringbuffer(
/*
- *
- * hv_copyto_ringbuffer()
- *
* Helper routine to copy from source to ring buffer.
* Assume there is enough room. Handles wrap-around in dest case only!!
- *
*/
static u32 hv_copyto_ringbuffer(
struct hv_ring_buffer_info *ring_info,
@@ -308,13 +260,7 @@ static u32 hv_copyto_ringbuffer(
return start_write_offset;
}
-/*
- *
- * hv_ringbuffer_get_debuginfo()
- *
- * Get various debug metrics for the specified ring buffer
- *
- */
+/* Get various debug metrics for the specified ring buffer. */
void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
struct hv_ring_buffer_debug_info *debug_info)
{
@@ -337,13 +283,7 @@ void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
}
}
-/*
- *
- * hv_ringbuffer_init()
- *
- *Initialize the ring buffer
- *
- */
+/* Initialize the ring buffer. */
int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
void *buffer, u32 buflen)
{
@@ -356,9 +296,7 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
ring_info->ring_buffer->read_index =
ring_info->ring_buffer->write_index = 0;
- /*
- * Set the feature bit for enabling flow control.
- */
+ /* Set the feature bit for enabling flow control. */
ring_info->ring_buffer->feature_bits.value = 1;
ring_info->ring_size = buflen;
@@ -369,24 +307,12 @@ int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
return 0;
}
-/*
- *
- * hv_ringbuffer_cleanup()
- *
- * Cleanup the ring buffer
- *
- */
+/* Cleanup the ring buffer. */
void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info)
{
}
-/*
- *
- * hv_ringbuffer_write()
- *
- * Write to the ring buffer
- *
- */
+/* Write to the ring buffer. */
int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
struct kvec *kv_list, u32 kv_count, bool *signal)
{
@@ -411,10 +337,11 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
&bytes_avail_toread,
&bytes_avail_towrite);
-
- /* If there is only room for the packet, assume it is full. */
- /* Otherwise, the next time around, we think the ring buffer */
- /* is empty since the read index == write index */
+ /*
+ * If there is only room for the packet, assume it is full.
+ * Otherwise, the next time around, we think the ring buffer
+ * is empty since the read index == write index.
+ */
if (bytes_avail_towrite <= totalbytes_towrite) {
spin_unlock_irqrestore(&outring_info->ring_lock, flags);
return -EAGAIN;
@@ -454,13 +381,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
}
-/*
- *
- * hv_ringbuffer_peek()
- *
- * Read without advancing the read index
- *
- */
+/* Read without advancing the read index. */
int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info,
void *Buffer, u32 buflen)
{
@@ -497,13 +418,7 @@ int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info,
}
-/*
- *
- * hv_ringbuffer_read()
- *
- * Read and advance the read index
- *
- */
+/* Read and advance the read index. */
int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
u32 buflen, u32 offset, bool *signal)
{
@@ -542,9 +457,11 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
sizeof(u64),
next_read_location);
- /* 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 */
+ /*
+ * 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.
+ */
mb();
/* Update the read index */
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 2/5] Drivers: hv: ring_buffer: remove stray smp_read_barrier_depends()
2015-12-08 17:07 [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 1/5] Drivers: hv: ring_buffer.c: fix comment style Vitaly Kuznetsov
@ 2015-12-08 17:07 ` Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 3/5] Drivers: hv: ring_buffer: remove code duplication from hv_ringbuffer_peek/read() Vitaly Kuznetsov
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Vitaly Kuznetsov @ 2015-12-08 17:07 UTC (permalink / raw)
To: devel; +Cc: K. Y. Srinivasan, Haiyang Zhang, linux-kernel
smp_read_barrier_depends() does nothing on almost all arcitectures
including x86 and having it in the beginning of
hv_get_ringbuffer_availbytes() does not provide any guarantees anyway.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
include/linux/hyperv.h | 2 --
1 file changed, 2 deletions(-)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 8fdc17b..1777dc8 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -141,8 +141,6 @@ hv_get_ringbuffer_availbytes(struct hv_ring_buffer_info *rbi,
{
u32 read_loc, write_loc, dsize;
- smp_read_barrier_depends();
-
/* Capture the read/write indices before they changed */
read_loc = rbi->ring_buffer->read_index;
write_loc = rbi->ring_buffer->write_index;
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 3/5] Drivers: hv: ring_buffer: remove code duplication from hv_ringbuffer_peek/read()
2015-12-08 17:07 [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 1/5] Drivers: hv: ring_buffer.c: fix comment style Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 2/5] Drivers: hv: ring_buffer: remove stray smp_read_barrier_depends() Vitaly Kuznetsov
@ 2015-12-08 17:07 ` Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 4/5] Drivers: hv: remove code duplication between vmbus_recvpacket()/vmbus_recvpacket_raw() Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 5/5] Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek() Vitaly Kuznetsov
4 siblings, 0 replies; 6+ messages in thread
From: Vitaly Kuznetsov @ 2015-12-08 17:07 UTC (permalink / raw)
To: devel; +Cc: K. Y. Srinivasan, Haiyang Zhang, linux-kernel
hv_ringbuffer_peek() does the same as hv_ringbuffer_read() without
advancing the read index. The only functional change this patch brings
is moving hv_need_to_signal_on_read() call under the ring_lock but this
function is just a couple of comparisons.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
drivers/hv/ring_buffer.c | 68 ++++++++++++++++++------------------------------
1 file changed, 25 insertions(+), 43 deletions(-)
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 7bca513..07f9408 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -380,47 +380,9 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
return 0;
}
-
-/* Read without advancing the read index. */
-int hv_ringbuffer_peek(struct hv_ring_buffer_info *Inring_info,
- void *Buffer, u32 buflen)
-{
- u32 bytes_avail_towrite;
- u32 bytes_avail_toread;
- u32 next_read_location = 0;
- unsigned long flags;
-
- spin_lock_irqsave(&Inring_info->ring_lock, flags);
-
- hv_get_ringbuffer_availbytes(Inring_info,
- &bytes_avail_toread,
- &bytes_avail_towrite);
-
- /* Make sure there is something to read */
- if (bytes_avail_toread < buflen) {
-
- spin_unlock_irqrestore(&Inring_info->ring_lock, flags);
-
- return -EAGAIN;
- }
-
- /* Convert to byte offset */
- next_read_location = hv_get_next_read_location(Inring_info);
-
- next_read_location = hv_copyfrom_ringbuffer(Inring_info,
- Buffer,
- buflen,
- next_read_location);
-
- spin_unlock_irqrestore(&Inring_info->ring_lock, flags);
-
- return 0;
-}
-
-
-/* Read and advance the read index. */
-int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
- u32 buflen, u32 offset, bool *signal)
+static inline int __hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
+ void *buffer, u32 buflen, u32 offset,
+ bool *signal, bool advance)
{
u32 bytes_avail_towrite;
u32 bytes_avail_toread;
@@ -452,6 +414,9 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
buflen,
next_read_location);
+ if (!advance)
+ goto out_unlock;
+
next_read_location = hv_copyfrom_ringbuffer(inring_info,
&prev_indices,
sizeof(u64),
@@ -467,9 +432,26 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer,
/* Update the read index */
hv_set_next_read_location(inring_info, next_read_location);
- spin_unlock_irqrestore(&inring_info->ring_lock, flags);
-
*signal = hv_need_to_signal_on_read(bytes_avail_towrite, inring_info);
+out_unlock:
+ spin_unlock_irqrestore(&inring_info->ring_lock, flags);
return 0;
}
+
+/* Read from ring buffer without advancing the read index. */
+int hv_ringbuffer_peek(struct hv_ring_buffer_info *inring_info,
+ void *buffer, u32 buflen)
+{
+ return __hv_ringbuffer_read(inring_info, buffer, buflen,
+ 0, NULL, false);
+}
+
+/* Read from ring buffer and advance the read index. */
+int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
+ void *buffer, u32 buflen, u32 offset,
+ bool *signal)
+{
+ return __hv_ringbuffer_read(inring_info, buffer, buflen,
+ offset, signal, true);
+}
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 4/5] Drivers: hv: remove code duplication between vmbus_recvpacket()/vmbus_recvpacket_raw()
2015-12-08 17:07 [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization Vitaly Kuznetsov
` (2 preceding siblings ...)
2015-12-08 17:07 ` [PATCH v2 3/5] Drivers: hv: ring_buffer: remove code duplication from hv_ringbuffer_peek/read() Vitaly Kuznetsov
@ 2015-12-08 17:07 ` Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 5/5] Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek() Vitaly Kuznetsov
4 siblings, 0 replies; 6+ messages in thread
From: Vitaly Kuznetsov @ 2015-12-08 17:07 UTC (permalink / raw)
To: devel; +Cc: K. Y. Srinivasan, Haiyang Zhang, linux-kernel
vmbus_recvpacket() and vmbus_recvpacket_raw() are almost identical but
there are two discrepancies:
1) vmbus_recvpacket() doesn't propagate errors from hv_ringbuffer_read()
which looks like it is not desired.
2) There is an error message printed in packetlen > bufferlen case in
vmbus_recvpacket(). I'm removing it as it is usless for users to see
such messages and /vmbus_recvpacket_raw() doesn't have it.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
drivers/hv/channel.c | 65 ++++++++++++++++++----------------------------------
1 file changed, 22 insertions(+), 43 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c4dcab0..c72271d 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -881,8 +881,10 @@ EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
*
* Mainly used by Hyper-V drivers.
*/
-int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
- u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
+static inline int
+__vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
+ u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
+ bool raw)
{
struct vmpacket_descriptor desc;
u32 packetlen;
@@ -900,27 +902,34 @@ int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
return 0;
packetlen = desc.len8 << 3;
- userlen = packetlen - (desc.offset8 << 3);
+ if (!raw)
+ userlen = packetlen - (desc.offset8 << 3);
+ else
+ userlen = packetlen;
*buffer_actual_len = userlen;
- if (userlen > bufferlen) {
-
- pr_err("Buffer too small - got %d needs %d\n",
- bufferlen, userlen);
- return -ETOOSMALL;
- }
+ if (userlen > bufferlen)
+ return -ENOBUFS;
*requestid = desc.trans_id;
/* Copy over the packet to the user buffer */
ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
- (desc.offset8 << 3), &signal);
+ raw ? 0 : desc.offset8 << 3, &signal);
if (signal)
vmbus_setevent(channel);
- return 0;
+ return ret;
+}
+
+int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
+ u32 bufferlen, u32 *buffer_actual_len,
+ u64 *requestid)
+{
+ return __vmbus_recvpacket(channel, buffer, bufferlen,
+ buffer_actual_len, requestid, false);
}
EXPORT_SYMBOL(vmbus_recvpacket);
@@ -931,37 +940,7 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
u32 bufferlen, u32 *buffer_actual_len,
u64 *requestid)
{
- struct vmpacket_descriptor desc;
- u32 packetlen;
- int ret;
- bool signal = false;
-
- *buffer_actual_len = 0;
- *requestid = 0;
-
-
- ret = hv_ringbuffer_peek(&channel->inbound, &desc,
- sizeof(struct vmpacket_descriptor));
- if (ret != 0)
- return 0;
-
-
- packetlen = desc.len8 << 3;
-
- *buffer_actual_len = packetlen;
-
- if (packetlen > bufferlen)
- return -ENOBUFS;
-
- *requestid = desc.trans_id;
-
- /* Copy over the entire packet to the user buffer */
- ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
- &signal);
-
- if (signal)
- vmbus_setevent(channel);
-
- return ret;
+ return __vmbus_recvpacket(channel, buffer, bufferlen,
+ buffer_actual_len, requestid, true);
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v2 5/5] Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek()
2015-12-08 17:07 [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization Vitaly Kuznetsov
` (3 preceding siblings ...)
2015-12-08 17:07 ` [PATCH v2 4/5] Drivers: hv: remove code duplication between vmbus_recvpacket()/vmbus_recvpacket_raw() Vitaly Kuznetsov
@ 2015-12-08 17:07 ` Vitaly Kuznetsov
4 siblings, 0 replies; 6+ messages in thread
From: Vitaly Kuznetsov @ 2015-12-08 17:07 UTC (permalink / raw)
To: devel; +Cc: K. Y. Srinivasan, Haiyang Zhang, linux-kernel
Currently, there is only one user for hv_ringbuffer_read()/
hv_ringbuffer_peak() functions and the usage of these functions is:
- insecure as we drop ring_lock between them, someone else (in theory
only) can acquire it in between;
- non-optimal as we do a number of things (acquire/release the above
mentioned lock, calculate available space on the ring, ...) twice and
this path is performance-critical.
Remove hv_ringbuffer_peek() moving the logic from __vmbus_recvpacket() to
hv_ringbuffer_read().
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
drivers/hv/channel.c | 30 ++--------------------
drivers/hv/hyperv_vmbus.h | 11 +++-----
drivers/hv/ring_buffer.c | 65 +++++++++++++++++++++++++++--------------------
3 files changed, 42 insertions(+), 64 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index c72271d..a4c800d 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -886,37 +886,11 @@ __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
bool raw)
{
- struct vmpacket_descriptor desc;
- u32 packetlen;
- u32 userlen;
int ret;
bool signal = false;
- *buffer_actual_len = 0;
- *requestid = 0;
-
-
- ret = hv_ringbuffer_peek(&channel->inbound, &desc,
- sizeof(struct vmpacket_descriptor));
- if (ret != 0)
- return 0;
-
- packetlen = desc.len8 << 3;
- if (!raw)
- userlen = packetlen - (desc.offset8 << 3);
- else
- userlen = packetlen;
-
- *buffer_actual_len = userlen;
-
- if (userlen > bufferlen)
- return -ENOBUFS;
-
- *requestid = desc.trans_id;
-
- /* Copy over the packet to the user buffer */
- ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
- raw ? 0 : desc.offset8 << 3, &signal);
+ ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen,
+ buffer_actual_len, requestid, &signal, raw);
if (signal)
vmbus_setevent(channel);
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 3782636..d5ee081 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -614,14 +614,9 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *ring_info,
struct kvec *kv_list,
u32 kv_count, bool *signal);
-int hv_ringbuffer_peek(struct hv_ring_buffer_info *ring_info, void *buffer,
- u32 buflen);
-
-int hv_ringbuffer_read(struct hv_ring_buffer_info *ring_info,
- void *buffer,
- u32 buflen,
- u32 offset, bool *signal);
-
+int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
+ void *buffer, u32 buflen, u32 *buffer_actual_len,
+ u64 *requestid, bool *signal, bool raw);
void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
struct hv_ring_buffer_debug_info *debug_info);
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 07f9408..b53702c 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -380,30 +380,59 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info,
return 0;
}
-static inline int __hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
- void *buffer, u32 buflen, u32 offset,
- bool *signal, bool advance)
+int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
+ void *buffer, u32 buflen, u32 *buffer_actual_len,
+ u64 *requestid, bool *signal, bool raw)
{
u32 bytes_avail_towrite;
u32 bytes_avail_toread;
u32 next_read_location = 0;
u64 prev_indices = 0;
unsigned long flags;
+ struct vmpacket_descriptor desc;
+ u32 offset;
+ u32 packetlen;
+ int ret = 0;
if (buflen <= 0)
return -EINVAL;
spin_lock_irqsave(&inring_info->ring_lock, flags);
+ *buffer_actual_len = 0;
+ *requestid = 0;
+
hv_get_ringbuffer_availbytes(inring_info,
&bytes_avail_toread,
&bytes_avail_towrite);
/* Make sure there is something to read */
- if (bytes_avail_toread < buflen) {
- spin_unlock_irqrestore(&inring_info->ring_lock, flags);
+ if (bytes_avail_toread < sizeof(desc)) {
+ /*
+ * No error is set when there is even no header, drivers are
+ * supposed to analyze buffer_actual_len.
+ */
+ goto out_unlock;
+ }
- return -EAGAIN;
+ next_read_location = hv_get_next_read_location(inring_info);
+ next_read_location = hv_copyfrom_ringbuffer(inring_info, &desc,
+ sizeof(desc),
+ next_read_location);
+
+ offset = raw ? 0 : (desc.offset8 << 3);
+ packetlen = (desc.len8 << 3) - offset;
+ *buffer_actual_len = packetlen;
+ *requestid = desc.trans_id;
+
+ if (bytes_avail_toread < packetlen + offset) {
+ ret = -EAGAIN;
+ goto out_unlock;
+ }
+
+ if (packetlen > buflen) {
+ ret = -ENOBUFS;
+ goto out_unlock;
}
next_read_location =
@@ -411,12 +440,9 @@ static inline int __hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
next_read_location = hv_copyfrom_ringbuffer(inring_info,
buffer,
- buflen,
+ packetlen,
next_read_location);
- if (!advance)
- goto out_unlock;
-
next_read_location = hv_copyfrom_ringbuffer(inring_info,
&prev_indices,
sizeof(u64),
@@ -436,22 +462,5 @@ static inline int __hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
out_unlock:
spin_unlock_irqrestore(&inring_info->ring_lock, flags);
- return 0;
-}
-
-/* Read from ring buffer without advancing the read index. */
-int hv_ringbuffer_peek(struct hv_ring_buffer_info *inring_info,
- void *buffer, u32 buflen)
-{
- return __hv_ringbuffer_read(inring_info, buffer, buflen,
- 0, NULL, false);
-}
-
-/* Read from ring buffer and advance the read index. */
-int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info,
- void *buffer, u32 buflen, u32 offset,
- bool *signal)
-{
- return __hv_ringbuffer_read(inring_info, buffer, buflen,
- offset, signal, true);
+ return ret;
}
--
2.4.3
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2015-12-08 17:08 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-08 17:07 [PATCH v2 0/5] Drivers: hv: ring_buffer: do some code cleanup and optimization Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 1/5] Drivers: hv: ring_buffer.c: fix comment style Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 2/5] Drivers: hv: ring_buffer: remove stray smp_read_barrier_depends() Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 3/5] Drivers: hv: ring_buffer: remove code duplication from hv_ringbuffer_peek/read() Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 4/5] Drivers: hv: remove code duplication between vmbus_recvpacket()/vmbus_recvpacket_raw() Vitaly Kuznetsov
2015-12-08 17:07 ` [PATCH v2 5/5] Drivers: hv: ring_buffer: eliminate hv_ringbuffer_peek() Vitaly Kuznetsov
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