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Date: Tue, 15 Nov 2011 16:36:46 +0800
From: Dave Young <dyoung@...hat.com>
To: gregkh@...e.de, tj@...nel.org, cl@...ux-foundation.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCCH percpu: add cpunum param in per_cpu_ptr_to_phys
per_cpu_ptr_to_phys iterate all cpu to get the phy addr
let's leave the caller to pass the cpu number to it.
Actually in the only one user show_crash_notes,
cpunum is provided already before calling this.
Signed-off-by: Dave Young <dyoung@...hat.com>
---
drivers/base/cpu.c | 2 +-
include/linux/percpu.h | 2 +-
mm/percpu.c | 29 ++++-------------------------
3 files changed, 6 insertions(+), 27 deletions(-)
--- linux-2.6.orig/drivers/base/cpu.c 2011-09-20 12:39:36.000000000 +0800
+++ linux-2.6/drivers/base/cpu.c 2011-11-15 14:52:42.742852411 +0800
@@ -125,7 +125,7 @@ static ssize_t show_crash_notes(struct s
* boot up and this data does not change there after. Hence this
* operation should be safe. No locking required.
*/
- addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
+ addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum), cpunum);
rc = sprintf(buf, "%Lx\n", addr);
return rc;
}
--- linux-2.6.orig/include/linux/percpu.h 2011-11-15 11:06:18.000000000 +0800
+++ linux-2.6/include/linux/percpu.h 2011-11-15 14:53:28.352605321 +0800
@@ -160,7 +160,7 @@ extern void __init percpu_init_late(void
extern void __percpu *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void __percpu *__pdata);
-extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
+extern phys_addr_t per_cpu_ptr_to_phys(void *addr, int cpunum);
#define alloc_percpu(type) \
(typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type))
--- linux-2.6.orig/mm/percpu.c 2011-11-15 11:06:19.000000000 +0800
+++ linux-2.6/mm/percpu.c 2011-11-15 14:59:56.927166899 +0800
@@ -971,6 +971,7 @@ bool is_kernel_percpu_address(unsigned l
/**
* per_cpu_ptr_to_phys - convert translated percpu address to physical address
* @addr: the address to be converted to physical address
+ * @cpunum: the cpu number of percpu address
*
* Given @addr which is dereferenceable address obtained via one of
* percpu access macros, this function translates it into its physical
@@ -980,34 +981,12 @@ bool is_kernel_percpu_address(unsigned l
* RETURNS:
* The physical address for @addr.
*/
-phys_addr_t per_cpu_ptr_to_phys(void *addr)
+phys_addr_t per_cpu_ptr_to_phys(void *addr, int cpunum)
{
void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
- bool in_first_chunk = false;
- unsigned long first_start, first_end;
- unsigned int cpu;
+ void *start = per_cpu_ptr(base, cpunum);
- /*
- * The following test on first_start/end isn't strictly
- * necessary but will speed up lookups of addresses which
- * aren't in the first chunk.
- */
- first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0);
- first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu,
- pcpu_unit_pages);
- if ((unsigned long)addr >= first_start &&
- (unsigned long)addr < first_end) {
- for_each_possible_cpu(cpu) {
- void *start = per_cpu_ptr(base, cpu);
-
- if (addr >= start && addr < start + pcpu_unit_size) {
- in_first_chunk = true;
- break;
- }
- }
- }
-
- if (in_first_chunk) {
+ if (addr >= start && addr < start + pcpu_unit_size) {
if (!is_vmalloc_addr(addr))
return __pa(addr);
else
--
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