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Subject[PATCH 1/4] Drivers: hv: cleanup vmbus_open() for wrap around mappings
Date
From: Vitaly Kuznetsov <vkuznets@redhat.com>

In preparation for doing wrap around mappings for ring buffers cleanup
vmbus_open() function:
- check that ring sizes are PAGE_SIZE aligned (they are for all in-kernel
drivers now);
- kfree(open_info) on error only after we kzalloc() it (not an issue as it
is valid to call kfree(NULL);
- rename poorly named labels;
- use alloc_pages() instead of __get_free_pages() as we need struct page
pointer for future.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Dexuan Cui <decui@microsoft.com>
---
drivers/hv/channel.c | 43 +++++++++++++++++++++++--------------------
1 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index e3a0048..901b6ce 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -81,6 +81,10 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
unsigned long t;
struct page *page;

+ if (send_ringbuffer_size % PAGE_SIZE ||
+ recv_ringbuffer_size % PAGE_SIZE)
+ return -EINVAL;
+
spin_lock_irqsave(&newchannel->lock, flags);
if (newchannel->state == CHANNEL_OPEN_STATE) {
newchannel->state = CHANNEL_OPENING_STATE;
@@ -100,17 +104,16 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
recv_ringbuffer_size));

if (!page)
- out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
- get_order(send_ringbuffer_size +
- recv_ringbuffer_size));
- else
- out = (void *)page_address(page);
+ page = alloc_pages(GFP_KERNEL|__GFP_ZERO,
+ get_order(send_ringbuffer_size +
+ recv_ringbuffer_size));

- if (!out) {
+ if (!page) {
err = -ENOMEM;
- goto error0;
+ goto error_set_chnstate;
}

+ out = page_address(page);
in = (void *)((unsigned long)out + send_ringbuffer_size);

newchannel->ringbuffer_pages = out;
@@ -122,14 +125,14 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,

if (ret != 0) {
err = ret;
- goto error0;
+ goto error_free_pages;
}

ret = hv_ringbuffer_init(
&newchannel->inbound, in, recv_ringbuffer_size);
if (ret != 0) {
err = ret;
- goto error0;
+ goto error_free_pages;
}


@@ -144,7 +147,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,

if (ret != 0) {
err = ret;
- goto error0;
+ goto error_free_pages;
}

/* Create and init the channel open message */
@@ -153,7 +156,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
GFP_KERNEL);
if (!open_info) {
err = -ENOMEM;
- goto error_gpadl;
+ goto error_free_gpadl;
}

init_completion(&open_info->waitevent);
@@ -169,7 +172,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,

if (userdatalen > MAX_USER_DEFINED_BYTES) {
err = -EINVAL;
- goto error_gpadl;
+ goto error_free_gpadl;
}

if (userdatalen)
@@ -185,13 +188,13 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,

if (ret != 0) {
err = ret;
- goto error1;
+ goto error_clean_msglist;
}

t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
if (t == 0) {
err = -ETIMEDOUT;
- goto error1;
+ goto error_clean_msglist;
}

spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
@@ -200,25 +203,25 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,

if (open_info->response.open_result.status) {
err = -EAGAIN;
- goto error_gpadl;
+ goto error_free_gpadl;
}

newchannel->state = CHANNEL_OPENED_STATE;
kfree(open_info);
return 0;

-error1:
+error_clean_msglist:
spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
list_del(&open_info->msglistentry);
spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);

-error_gpadl:
+error_free_gpadl:
vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
-
-error0:
+ kfree(open_info);
+error_free_pages:
free_pages((unsigned long)out,
get_order(send_ringbuffer_size + recv_ringbuffer_size));
- kfree(open_info);
+error_set_chnstate:
newchannel->state = CHANNEL_OPEN_STATE;
return err;
}
--
1.7.4.1
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