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Subject[PATCH 2/5] uprobes: Change __copy_insn() to use copy_from_page()
Change __copy_insn() to use copy_from_page() and simplify the code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/events/uprobes.c | 13 ++-----------
1 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index d6891cb..0a759c6 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -477,30 +477,21 @@ __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
unsigned long nbytes, loff_t offset)
{
struct page *page;
- void *vaddr;
- unsigned long off;
- pgoff_t idx;

if (!filp)
return -EINVAL;

if (!mapping->a_ops->readpage)
return -EIO;
-
- idx = offset >> PAGE_CACHE_SHIFT;
- off = offset & ~PAGE_MASK;
-
/*
* Ensure that the page that has the original instruction is
* populated and in page-cache.
*/
- page = read_mapping_page(mapping, idx, filp);
+ page = read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT, filp);
if (IS_ERR(page))
return PTR_ERR(page);

- vaddr = kmap_atomic(page);
- memcpy(insn, vaddr + off, nbytes);
- kunmap_atomic(vaddr);
+ copy_from_page(page, offset, insn, nbytes);
page_cache_release(page);

return 0;
--
1.5.5.1


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