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Subject[RESEND PATCH 1/3] uprobes: Remove redundant lock_page/unlock_page
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

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>
---
Modified changelog based on comments from Peter Zijlstra

kernel/events/uprobes.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 42b21eb..b3f3095 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -315,12 +315,10 @@ 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);



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