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Subject[PATCH AUTOSEL 4.19 123/191] vmbus: keep pointer to ring buffer page
Date
From: Stephen Hemminger <stephen@networkplumber.org>

[ Upstream commit 52a42c2a90226dc61c99bbd0cb096deeb52c334b ]

Avoid going from struct page to virt address (and back) by just
keeping pointer to the allocated pages instead of virt address.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hv/channel.c | 20 +++++++++-----------
drivers/uio/uio_hv_generic.c | 5 +++--
include/linux/hyperv.h | 2 +-
3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index fdb0f832fadef..5e515533e9cdb 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -91,11 +91,14 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
unsigned long flags;
int ret, err = 0;
struct page *page;
+ unsigned int order;

if (send_ringbuffer_size % PAGE_SIZE ||
recv_ringbuffer_size % PAGE_SIZE)
return -EINVAL;

+ order = get_order(send_ringbuffer_size + recv_ringbuffer_size);
+
spin_lock_irqsave(&newchannel->lock, flags);
if (newchannel->state == CHANNEL_OPEN_STATE) {
newchannel->state = CHANNEL_OPENING_STATE;
@@ -110,21 +113,17 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,

/* Allocate the ring buffer */
page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
- GFP_KERNEL|__GFP_ZERO,
- get_order(send_ringbuffer_size +
- recv_ringbuffer_size));
+ GFP_KERNEL|__GFP_ZERO, order);

if (!page)
- page = alloc_pages(GFP_KERNEL|__GFP_ZERO,
- get_order(send_ringbuffer_size +
- recv_ringbuffer_size));
+ page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order);

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

- newchannel->ringbuffer_pages = page_address(page);
+ newchannel->ringbuffer_page = page;
newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
recv_ringbuffer_size) >> PAGE_SHIFT;

@@ -239,8 +238,7 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
error_free_pages:
hv_ringbuffer_cleanup(&newchannel->outbound);
hv_ringbuffer_cleanup(&newchannel->inbound);
- __free_pages(page,
- get_order(send_ringbuffer_size + recv_ringbuffer_size));
+ __free_pages(page, order);
error_set_chnstate:
newchannel->state = CHANNEL_OPEN_STATE;
return err;
@@ -666,8 +664,8 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
hv_ringbuffer_cleanup(&channel->outbound);
hv_ringbuffer_cleanup(&channel->inbound);

- free_pages((unsigned long)channel->ringbuffer_pages,
- get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
+ __free_pages(channel->ringbuffer_page,
+ get_order(channel->ringbuffer_pagecount << PAGE_SHIFT));

out:
return ret;
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index e401be8321ab5..170fa1f8f00e0 100644
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -131,11 +131,12 @@ static int hv_uio_ring_mmap(struct file *filp, struct kobject *kobj,
= container_of(kobj, struct vmbus_channel, kobj);
struct hv_device *dev = channel->primary_channel->device_obj;
u16 q_idx = channel->offermsg.offer.sub_channel_index;
+ void *ring_buffer = page_address(channel->ringbuffer_page);

dev_dbg(&dev->device, "mmap channel %u pages %#lx at %#lx\n",
q_idx, vma_pages(vma), vma->vm_pgoff);

- return vm_iomap_memory(vma, virt_to_phys(channel->ringbuffer_pages),
+ return vm_iomap_memory(vma, virt_to_phys(ring_buffer),
channel->ringbuffer_pagecount << PAGE_SHIFT);
}

@@ -224,7 +225,7 @@ hv_uio_probe(struct hv_device *dev,
/* mem resources */
pdata->info.mem[TXRX_RING_MAP].name = "txrx_rings";
pdata->info.mem[TXRX_RING_MAP].addr
- = (uintptr_t)dev->channel->ringbuffer_pages;
+ = (uintptr_t)page_address(dev->channel->ringbuffer_page);
pdata->info.mem[TXRX_RING_MAP].size
= dev->channel->ringbuffer_pagecount << PAGE_SHIFT;
pdata->info.mem[TXRX_RING_MAP].memtype = UIO_MEM_LOGICAL;
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index bbde887ed3931..c43e694fef7dd 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -739,7 +739,7 @@ struct vmbus_channel {
u32 ringbuffer_gpadlhandle;

/* Allocated memory for ring buffer */
- void *ringbuffer_pages;
+ struct page *ringbuffer_page;
u32 ringbuffer_pagecount;
struct hv_ring_buffer_info outbound; /* send to parent */
struct hv_ring_buffer_info inbound; /* receive from parent */
--
2.20.1
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