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Subject[PATCH 4/5] uprobes: Introduce copy_to_page()
Extract the kmap_atomic/memcpy/kunmap_atomic code from
xol_get_insn_slot() into the new simple helper, copy_to_page().
It will have more users soon.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/events/uprobes.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index e5d479f..9d943f7 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -180,6 +180,13 @@ static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, in
kunmap_atomic(kaddr);
}

+static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
+{
+ void *kaddr = kmap_atomic(page);
+ memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
+ kunmap_atomic(kaddr);
+}
+
static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
{
uprobe_opcode_t old_opcode;
@@ -1204,9 +1211,7 @@ static unsigned long xol_take_insn_slot(struct xol_area *area)
static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
{
struct xol_area *area;
- unsigned long offset;
unsigned long xol_vaddr;
- void *vaddr;

area = get_xol_area();
if (!area)
@@ -1217,10 +1222,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
return 0;

/* Initialize the slot */
- offset = xol_vaddr & ~PAGE_MASK;
- vaddr = kmap_atomic(area->page);
- memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
- kunmap_atomic(vaddr);
+ copy_to_page(area->page, xol_vaddr, uprobe->arch.insn, MAX_UINSN_BYTES);
/*
* We probably need flush_icache_user_range() but it needs vma.
* This should work on supported architectures too.
--
1.5.5.1


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