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Subject[PATCH 08/10] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv
Date
Replacing alloc_vm_area with get_vm_area_caller + apply_page_range
allows to fill put the phys_addr values directly instead of doing
another loop over all addresses.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
drivers/xen/xenbus/xenbus_client.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 2690318ad50f48..fd80e318b99cc7 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -73,16 +73,13 @@ struct map_ring_valloc {
struct xenbus_map_node *node;

/* Why do we need two arrays? See comment of __xenbus_map_ring */
- union {
- unsigned long addrs[XENBUS_MAX_RING_GRANTS];
- pte_t *ptes[XENBUS_MAX_RING_GRANTS];
- };
+ unsigned long addrs[XENBUS_MAX_RING_GRANTS];
phys_addr_t phys_addrs[XENBUS_MAX_RING_GRANTS];

struct gnttab_map_grant_ref map[XENBUS_MAX_RING_GRANTS];
struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_GRANTS];

- unsigned int idx; /* HVM only. */
+ unsigned int idx;
};

static DEFINE_SPINLOCK(xenbus_valloc_lock);
@@ -686,6 +683,14 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);

#ifdef CONFIG_XEN_PV
+static int map_ring_apply(pte_t *pte, unsigned long addr, void *data)
+{
+ struct map_ring_valloc *info = data;
+
+ info->phys_addrs[info->idx++] = arbitrary_virt_to_machine(pte).maddr;
+ return 0;
+}
+
static int xenbus_map_ring_pv(struct xenbus_device *dev,
struct map_ring_valloc *info,
grant_ref_t *gnt_refs,
@@ -694,18 +699,15 @@ static int xenbus_map_ring_pv(struct xenbus_device *dev,
{
struct xenbus_map_node *node = info->node;
struct vm_struct *area;
- int err = GNTST_okay;
- int i;
- bool leaked;
+ bool leaked = false;
+ int err = -ENOMEM;

- area = alloc_vm_area(XEN_PAGE_SIZE * nr_grefs, info->ptes);
+ area = get_vm_area(XEN_PAGE_SIZE * nr_grefs, VM_IOREMAP);
if (!area)
return -ENOMEM;
-
- for (i = 0; i < nr_grefs; i++)
- info->phys_addrs[i] =
- arbitrary_virt_to_machine(info->ptes[i]).maddr;
-
+ if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
+ XEN_PAGE_SIZE * nr_grefs, map_ring_apply, info))
+ goto failed;
err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
info, GNTMAP_host_map | GNTMAP_contains_pte,
&leaked);
--
2.28.0
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