[PATCH 1/2] hv_balloon: Use a static page for the balloon_up send buffer

From: Dexuan Cui
Date: Fri Jun 14 2019 - 14:47:09 EST


It's unnecessary to dynamically allocate the buffer.

Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
---
drivers/hv/hv_balloon.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index dd475f3bcc8a..13381ea3e3e7 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -504,7 +504,7 @@ enum hv_dm_state {


static __u8 recv_buffer[PAGE_SIZE];
-static __u8 *send_buffer;
+static __u8 balloon_up_send_buffer[PAGE_SIZE];
#define PAGES_IN_2M 512
#define HA_CHUNK (32 * 1024)

@@ -1302,8 +1302,8 @@ static void balloon_up(struct work_struct *dummy)
}

while (!done) {
- bl_resp = (struct dm_balloon_response *)send_buffer;
- memset(send_buffer, 0, PAGE_SIZE);
+ memset(balloon_up_send_buffer, 0, PAGE_SIZE);
+ bl_resp = (struct dm_balloon_response *)balloon_up_send_buffer;
bl_resp->hdr.type = DM_BALLOON_RESPONSE;
bl_resp->hdr.size = sizeof(struct dm_balloon_response);
bl_resp->more_pages = 1;
@@ -1588,19 +1588,11 @@ static int balloon_probe(struct hv_device *dev,
do_hot_add = false;
#endif

- /*
- * First allocate a send buffer.
- */
-
- send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
- if (!send_buffer)
- return -ENOMEM;
-
ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
balloon_onchannelcallback, dev);

if (ret)
- goto probe_error0;
+ return ret;

dm_device.dev = dev;
dm_device.state = DM_INITIALIZING;
@@ -1726,8 +1718,6 @@ static int balloon_probe(struct hv_device *dev,

probe_error1:
vmbus_close(dev->channel);
-probe_error0:
- kfree(send_buffer);
return ret;
}

@@ -1746,7 +1736,6 @@ static int balloon_remove(struct hv_device *dev)

vmbus_close(dev->channel);
kthread_stop(dm->thread);
- kfree(send_buffer);
#ifdef CONFIG_MEMORY_HOTPLUG
restore_online_page_callback(&hv_online_page);
unregister_memory_notifier(&hv_memory_nb);
--
2.19.1