[36/40] x86/xen: open code alloc_vm_area in arch_gnttab_valloc

Commit Message

Andrew Morton Oct. 17, 2020, 11:15 p.m. UTC

From: Christoph Hellwig <[e-mail]>
Subject: x86/xen: open code alloc_vm_area in arch_gnttab_valloc

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.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Boris Ostrovsky <[e-mail]>
Cc: Chris Wilson <[e-mail]>
Cc: Jani Nikula <[e-mail]>
Cc: Joonas Lahtinen <[e-mail]>
Cc: Juergen Gross <[e-mail]>
Cc: Matthew Auld <[e-mail]>
Cc: "Matthew Wilcox (Oracle)" <[e-mail]>
Cc: Minchan Kim <[e-mail]>
Cc: Nitin Gupta <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Rodrigo Vivi <[e-mail]>
Cc: Stefano Stabellini <[e-mail]>
Cc: Tvrtko Ursulin <[e-mail]>
Cc: Uladzislau Rezki (Sony) <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 arch/x86/xen/grant-table.c |   27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

Patch

--- a/arch/x86/xen/grant-table.c~x86-xen-open-code-alloc_vm_area-in-arch_gnttab_valloc
+++ a/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, uns
 	}
 }
 
+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)