From 244b2c5ca8b14627e4a17755e5922221e121c771 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 09 Oct 2024 06:15:07 +0000
Subject: [PATCH] change system file
---
kernel/drivers/hv/ring_buffer.c | 78 +++++++++++++++++++++++++++++----------
1 files changed, 58 insertions(+), 20 deletions(-)
diff --git a/kernel/drivers/hv/ring_buffer.c b/kernel/drivers/hv/ring_buffer.c
index 6cb45f2..7ed6fad 100644
--- a/kernel/drivers/hv/ring_buffer.c
+++ b/kernel/drivers/hv/ring_buffer.c
@@ -1,25 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (c) 2009, Microsoft Corporation.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
- * Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Authors:
* Haiyang Zhang <haiyangz@microsoft.com>
* Hank Janssen <hjanssen@microsoft.com>
* K. Y. Srinivasan <kys@microsoft.com>
- *
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -74,8 +61,10 @@
* This is the only case we need to signal when the
* ring transitions from being empty to non-empty.
*/
- if (old_write == READ_ONCE(rbi->ring_buffer->read_index))
+ if (old_write == READ_ONCE(rbi->ring_buffer->read_index)) {
+ ++channel->intr_out_empty;
vmbus_setevent(channel);
+ }
}
/* Get the next write location for the specified ring buffer. */
@@ -164,14 +153,18 @@
}
/* Get various debug metrics for the specified ring buffer. */
-int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+int hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,
struct hv_ring_buffer_debug_info *debug_info)
{
u32 bytes_avail_towrite;
u32 bytes_avail_toread;
- if (!ring_info->ring_buffer)
+ mutex_lock(&ring_info->ring_buffer_mutex);
+
+ if (!ring_info->ring_buffer) {
+ mutex_unlock(&ring_info->ring_buffer_mutex);
return -EINVAL;
+ }
hv_get_ringbuffer_availbytes(ring_info,
&bytes_avail_toread,
@@ -182,9 +175,18 @@
debug_info->current_write_index = ring_info->ring_buffer->write_index;
debug_info->current_interrupt_mask
= ring_info->ring_buffer->interrupt_mask;
+ mutex_unlock(&ring_info->ring_buffer_mutex);
+
return 0;
}
EXPORT_SYMBOL_GPL(hv_ringbuffer_get_debuginfo);
+
+/* Initialize a channel's ring buffer info mutex locks */
+void hv_ringbuffer_pre_init(struct vmbus_channel *channel)
+{
+ mutex_init(&channel->inbound.ring_buffer_mutex);
+ mutex_init(&channel->outbound.ring_buffer_mutex);
+}
/* Initialize the ring buffer. */
int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
@@ -194,8 +196,6 @@
struct page **pages_wraparound;
BUILD_BUG_ON((sizeof(struct hv_ring_buffer) != PAGE_SIZE));
-
- memset(ring_info, 0, sizeof(struct hv_ring_buffer_info));
/*
* First page holds struct hv_ring_buffer, do wraparound mapping for
@@ -230,6 +230,7 @@
reciprocal_value(ring_info->ring_size / 10);
ring_info->ring_datasize = ring_info->ring_size -
sizeof(struct hv_ring_buffer);
+ ring_info->priv_read_index = 0;
spin_lock_init(&ring_info->ring_lock);
@@ -239,8 +240,24 @@
/* Cleanup the ring buffer. */
void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info)
{
+ mutex_lock(&ring_info->ring_buffer_mutex);
vunmap(ring_info->ring_buffer);
+ ring_info->ring_buffer = NULL;
+ mutex_unlock(&ring_info->ring_buffer_mutex);
}
+
+/*
+ * Check if the ring buffer spinlock is available to take or not; used on
+ * atomic contexts, like panic path (see the Hyper-V framebuffer driver).
+ */
+
+bool hv_ringbuffer_spinlock_busy(struct vmbus_channel *channel)
+{
+ struct hv_ring_buffer_info *rinfo = &channel->outbound;
+
+ return spin_is_locked(&rinfo->ring_lock);
+}
+EXPORT_SYMBOL_GPL(hv_ringbuffer_spinlock_busy);
/* Write to the ring buffer. */
int hv_ringbuffer_write(struct vmbus_channel *channel,
@@ -271,9 +288,18 @@
* is empty since the read index == write index.
*/
if (bytes_avail_towrite <= totalbytes_towrite) {
+ ++channel->out_full_total;
+
+ if (!channel->out_full_flag) {
+ ++channel->out_full_first;
+ channel->out_full_flag = true;
+ }
+
spin_unlock_irqrestore(&outring_info->ring_lock, flags);
return -EAGAIN;
}
+
+ channel->out_full_flag = false;
/* Write to the ring buffer */
next_write_location = hv_get_next_write_location(outring_info);
@@ -365,7 +391,16 @@
static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
{
u32 priv_read_loc = rbi->priv_read_index;
- u32 write_loc = READ_ONCE(rbi->ring_buffer->write_index);
+ u32 write_loc;
+
+ /*
+ * The Hyper-V host writes the packet data, then uses
+ * store_release() to update the write_index. Use load_acquire()
+ * here to prevent loads of the packet data from being re-ordered
+ * before the read of the write_index and potentially getting
+ * stale data.
+ */
+ write_loc = virt_load_acquire(&rbi->ring_buffer->write_index);
if (write_loc >= priv_read_loc)
return write_loc - priv_read_loc;
@@ -383,6 +418,7 @@
struct hv_ring_buffer_info *rbi = &channel->inbound;
struct vmpacket_descriptor *desc;
+ hv_debug_delay_test(channel, MESSAGE_DELAY);
if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))
return NULL;
@@ -408,6 +444,7 @@
u32 packetlen = desc->len8 << 3;
u32 dsize = rbi->ring_datasize;
+ hv_debug_delay_test(channel, MESSAGE_DELAY);
/* bump offset to next potential packet */
rbi->priv_read_index += packetlen + VMBUS_PKT_TRAILER;
if (rbi->priv_read_index >= dsize)
@@ -529,6 +566,7 @@
if (curr_write_sz <= pending_sz)
return;
+ ++channel->intr_in_full;
vmbus_setevent(channel);
}
EXPORT_SYMBOL_GPL(hv_pkt_iter_close);
--
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