uprobes: Remove redundant lock_page/unlock_page

Since read_opcode() reads from the referenced page and doesnt modify
the page contents nor the page attributes, there is no need to lock
the page.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c08a22d..7cff24c 100644 (file)
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -280,12 +280,10 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_
        if (ret <= 0)
                return ret;
 
-       lock_page(page);
        vaddr_new = kmap_atomic(page);
        vaddr &= ~PAGE_MASK;
        memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE);
        kunmap_atomic(vaddr_new);
-       unlock_page(page);
 
        put_page(page);