* [PATCH] kernel: events: use offset_in_page macro
@ 2020-06-30 7:42 Chen Ni
2020-06-30 7:50 ` Peter Zijlstra
0 siblings, 1 reply; 3+ messages in thread
From: Chen Ni @ 2020-06-30 7:42 UTC (permalink / raw)
To: peterz, mingo, acme, mark.rutland, alexander.shishkin, jolsa, namhyung
Cc: linux-kernel, Xu Wang
From: Xu Wang <vulab@iscas.ac.cn>
Use offset_in_page macro instead of (addr & ~PAGE_MASK).
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
---
kernel/events/uprobes.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index bb0862873dba..44d175d81ed6 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -244,14 +244,14 @@ bool __weak is_trap_insn(uprobe_opcode_t *insn)
static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
{
void *kaddr = kmap_atomic(page);
- memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
+ memcpy(dst, kaddr + offset_in_page(vaddr), len);
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);
+ memcpy(kaddr + offset_in_page(vaddr), src, len);
kunmap_atomic(kaddr);
}
@@ -387,7 +387,7 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d)
}
kaddr = kmap_atomic(page);
- ptr = kaddr + (vaddr & ~PAGE_MASK);
+ ptr = kaddr + offset_in_page(vaddr);
if (unlikely(*ptr + d < 0)) {
pr_warn("ref_ctr going negative. vaddr: 0x%lx, "
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] kernel: events: use offset_in_page macro
2020-06-30 7:42 [PATCH] kernel: events: use offset_in_page macro Chen Ni
@ 2020-06-30 7:50 ` Peter Zijlstra
0 siblings, 0 replies; 3+ messages in thread
From: Peter Zijlstra @ 2020-06-30 7:50 UTC (permalink / raw)
To: Chen Ni
Cc: mingo, acme, mark.rutland, alexander.shishkin, jolsa, namhyung,
linux-kernel
On Tue, Jun 30, 2020 at 07:42:58AM +0000, Chen Ni wrote:
> Use offset_in_page macro instead of (addr & ~PAGE_MASK).
Shees, so now we're replacing a trivial expression with something that's
actually longer to type? How does that make sense?
> - memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
> + memcpy(dst, kaddr + offset_in_page(vaddr), len);
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] kernel: events: use offset_in_page macro
@ 2020-05-13 2:28 Xu Wang
0 siblings, 0 replies; 3+ messages in thread
From: Xu Wang @ 2020-05-13 2:28 UTC (permalink / raw)
To: peterz, mingo, acme, mark.rutland, alexander.shishkin, jolsa, amhyung
Cc: linux-kernel
Use offset_in_page macro instead of (addr & ~PAGE_MASK).
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
---
kernel/events/uprobes.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index ece7e13..1552ef1 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -250,14 +250,14 @@ bool __weak is_trap_insn(uprobe_opcode_t *insn)
static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
{
void *kaddr = kmap_atomic(page);
- memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
+ memcpy(dst, kaddr + offset_in_page(vaddr), len);
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);
+ memcpy(kaddr + offset_in_page(vaddr), src, len);
kunmap_atomic(kaddr);
}
@@ -393,7 +393,7 @@ __update_ref_ctr(struct mm_struct *mm, unsigned long vaddr, short d)
}
kaddr = kmap_atomic(page);
- ptr = kaddr + (vaddr & ~PAGE_MASK);
+ ptr = kaddr + offset_in_page(vaddr);
if (unlikely(*ptr + d < 0)) {
pr_warn("ref_ctr going negative. vaddr: 0x%lx, "
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2020-06-30 7:42 [PATCH] kernel: events: use offset_in_page macro Chen Ni
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2020-05-13 2:28 Xu Wang
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