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Subject[PATCH 09/10] x86/xen: open code alloc_vm_area in arch_gnttab_valloc
Date
Replace the last call to alloc_vm_area with an open coded version using
an iterator in struct gnttab_vm_area instead of the triple indirection
magic in alloc_vm_area.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
arch/x86/xen/grant-table.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/arch/x86/xen/grant-table.c b/arch/x86/xen/grant-table.c
index 4988e19598c8a5..1e681bf62561a0 100644
--- a/arch/x86/xen/grant-table.c
+++ b/arch/x86/xen/grant-table.c
@@ -25,6 +25,7 @@
static struct gnttab_vm_area {
struct vm_struct *area;
pte_t **ptes;
+ int idx;
} gnttab_shared_vm_area, gnttab_status_vm_area;

int arch_gnttab_map_shared(unsigned long *frames, unsigned long nr_gframes,
@@ -90,19 +91,31 @@ void arch_gnttab_unmap(void *shared, unsigned long nr_gframes)
}
}

+static int gnttab_apply(pte_t *pte, unsigned long addr, void *data)
+{
+ struct gnttab_vm_area *area = data;
+
+ area->ptes[area->idx++] = pte;
+ return 0;
+}
+
static int arch_gnttab_valloc(struct gnttab_vm_area *area, unsigned nr_frames)
{
area->ptes = kmalloc_array(nr_frames, sizeof(*area->ptes), GFP_KERNEL);
if (area->ptes == NULL)
return -ENOMEM;
-
- area->area = alloc_vm_area(PAGE_SIZE * nr_frames, area->ptes);
- if (area->area == NULL) {
- kfree(area->ptes);
- return -ENOMEM;
- }
-
+ area->area = get_vm_area(PAGE_SIZE * nr_frames, VM_IOREMAP);
+ if (!area->area)
+ goto out_free_ptes;
+ if (apply_to_page_range(&init_mm, (unsigned long)area->area->addr,
+ PAGE_SIZE * nr_frames, gnttab_apply, area))
+ goto out_free_vm_area;
return 0;
+out_free_vm_area:
+ free_vm_area(area->area);
+out_free_ptes:
+ kfree(area->ptes);
+ return -ENOMEM;
}

static void arch_gnttab_vfree(struct gnttab_vm_area *area)
--
2.28.0
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