From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: devel@linuxdriverproject.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/5] Drivers: hv: ring_buffer: remove code duplication from hv_ringbuffer_peek/read()
Date: Tue, 8 Dec 2015 18:07:38 +0100 [thread overview]
Message-ID: <1449594460-22588-4-git-send-email-vkuznets@redhat.com> (raw)
In-Reply-To: <1449594460-22588-1-git-send-email-vkuznets@redhat.com>
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
next prev parent reply other threads:[~2015-12-08 17:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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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