Drivers: hv: cleanup vmbus_open() for wrap around mappings

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>
Tested-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 884cebf..15e8330 100644 (file)
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -80,6 +80,10 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
        int ret, err = 0;
        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;
@@ -99,17 +103,16 @@ 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;
@@ -121,14 +124,14 @@ 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;
        }
 
 
@@ -143,7 +146,7 @@ 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 */
@@ -152,7 +155,7 @@ 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);
@@ -168,7 +171,7 @@ 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)
@@ -184,7 +187,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
 
        if (ret != 0) {
                err = ret;
-               goto error1;
+               goto error_clean_msglist;
        }
 
        wait_for_completion(&open_info->waitevent);
@@ -195,25 +198,25 @@ 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;
 }