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Date: Tue, 20 May 2008 17:42:03 +0200
From: Peter Oberparleiter <peter.oberparleiter@...ibm.com>
To: Andrew Morton <akpm@...ux-foundation.org>
CC: Harvey Harrison <harvey.harrison@...il.com>,
Peter Oberparleiter <peter.oberparleiter@...ibm.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] consolidate all within() implementations
Andrew Morton wrote:
> On Tue, 20 May 2008 10:08:32 +0200 Peter Oberparleiter <oberparleiter@...glemail.com> wrote:
>> +/**
>> + * addr_within_len - check whether address is in start-and-length address range
>> + * @addr: address
>> + * @start: start of range
>> + * @len: number of bytes in range
>> + */
>> +static inline int addr_within_len(unsigned long addr, unsigned long start,
>> + unsigned long len)
>> +{
>> + return (addr >= start) && (addr < (start + len));
>> +}
>
> The kernel's use of unsigned long to represent pointers sometimes makes
> sense, but often gets us into a mess. It's OK in bootup code which
> fiddles with memory map layout because there is no reason why such
> code will ever dereference any of the addresses.
>
> But I don't think we can assume this usage pattern when creating a
> kernel-wide facility in kernel.h.
>
> So yes, I do think that an address-comparison tool like this should
> operate on void*'s. (They will need to be const void*'s).
Now that every line using a within() has to be changed anyway, it could
as well be done right, yes.
> And you've had to add a great pile of casts anwyay?
Well, between the unsigned long and the void * version, there's not that
much of a difference in the number of casts. So here goes #3:
--
From: Peter Oberparleiter <peter.oberparleiter@...ibm.com>
This patch consolidates a number of different implementations of the
within() function which checks whether an address is within a specified
address range. Apart from parameter typing, existing implementations can
be classified in two categories which differ in the way the range is
specified:
1) by start and end address
2) by start and size
Case 1) is covered by addr_within() while 2) is covered by
addr_within_len().
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@...ibm.com>
---
arch/x86/mm/pageattr.c | 26 ++++++++++++--------------
include/linux/kernel.h | 26 ++++++++++++++++++++++++++
kernel/lockdep.c | 10 +++-------
kernel/module.c | 34 +++++++++++++++++++---------------
4 files changed, 60 insertions(+), 36 deletions(-)
Index: linux-2.6.26-rc3/include/linux/kernel.h
===================================================================
--- linux-2.6.26-rc3.orig/include/linux/kernel.h
+++ linux-2.6.26-rc3/include/linux/kernel.h
@@ -434,6 +434,32 @@ static inline char *pack_hex_byte(char *
__val > __max ? __max: __val; })
/**
+ * addr_within - check whether address is in start-and-end address range
+ * @addr: address
+ * @start: start address (included in range)
+ * @end: end address (excluded from range)
+ */
+static inline int addr_within(const void *addr, const void *start,
+ const void *end)
+{
+ return ((unsigned long) addr >= (unsigned long) start) &&
+ ((unsigned long) addr < (unsigned long) end);
+}
+
+/**
+ * addr_within_len - check whether address is in start-and-length address range
+ * @addr: address
+ * @start: start of range
+ * @len: number of bytes in range
+ */
+static inline int addr_within_len(const void *addr, const void *start,
+ size_t len)
+{
+ return ((unsigned long) addr >= (unsigned long) start) &&
+ ((unsigned long) addr < ((unsigned long) start + len));
+}
+
+/**
* container_of - cast a member of a structure out to the containing structure
* @ptr: the pointer to the member.
* @type: the type of the container struct this is embedded in.
Index: linux-2.6.26-rc3/kernel/lockdep.c
===================================================================
--- linux-2.6.26-rc3.orig/kernel/lockdep.c
+++ linux-2.6.26-rc3/kernel/lockdep.c
@@ -25,6 +25,7 @@
* Thanks to Arjan van de Ven for coming up with the initial idea of
* mapping lock dependencies runtime.
*/
+#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/sched.h>
#include <linux/delay.h>
@@ -2932,11 +2933,6 @@ static void zap_class(struct lock_class
}
-static inline int within(const void *addr, void *start, unsigned long size)
-{
- return addr >= start && addr < start + size;
-}
-
void lockdep_free_key_range(void *start, unsigned long size)
{
struct lock_class *class, *next;
@@ -2956,9 +2952,9 @@ void lockdep_free_key_range(void *start,
if (list_empty(head))
continue;
list_for_each_entry_safe(class, next, head, hash_entry) {
- if (within(class->key, start, size))
+ if (addr_within_len(class->key, start, size))
zap_class(class);
- else if (within(class->name, start, size))
+ else if (addr_within_len(class->name, start, size))
zap_class(class);
}
}
Index: linux-2.6.26-rc3/kernel/module.c
===================================================================
--- linux-2.6.26-rc3.orig/kernel/module.c
+++ linux-2.6.26-rc3/kernel/module.c
@@ -2262,11 +2262,6 @@ sys_init_module(void __user *umod,
return 0;
}
-static inline int within(unsigned long addr, void *start, unsigned long size)
-{
- return ((void *)addr >= start && (void *)addr < start + size);
-}
-
#ifdef CONFIG_KALLSYMS
/*
* This ignores the intensely annoying "mapping symbols" found
@@ -2287,7 +2282,7 @@ static const char *get_ksymbol(struct mo
unsigned long nextval;
/* At worse, next value is at end of module */
- if (within(addr, mod->module_init, mod->init_size))
+ if (addr_within_len((void *) addr, mod->module_init, mod->init_size))
nextval = (unsigned long)mod->module_init+mod->init_text_size;
else
nextval = (unsigned long)mod->module_core+mod->core_text_size;
@@ -2335,8 +2330,10 @@ const char *module_address_lookup(unsign
preempt_disable();
list_for_each_entry(mod, &modules, list) {
- if (within(addr, mod->module_init, mod->init_size)
- || within(addr, mod->module_core, mod->core_size)) {
+ if (addr_within_len((void *) addr, mod->module_init,
+ mod->init_size)
+ || addr_within_len((void *) addr, mod->module_core,
+ mod->core_size)) {
if (modname)
*modname = mod->name;
ret = get_ksymbol(mod, addr, size, offset);
@@ -2358,8 +2355,10 @@ int lookup_module_symbol_name(unsigned l
preempt_disable();
list_for_each_entry(mod, &modules, list) {
- if (within(addr, mod->module_init, mod->init_size) ||
- within(addr, mod->module_core, mod->core_size)) {
+ if (addr_within_len((void *) addr, mod->module_init,
+ mod->init_size) ||
+ addr_within_len((void *) addr, mod->module_core,
+ mod->core_size)) {
const char *sym;
sym = get_ksymbol(mod, addr, NULL, NULL);
@@ -2382,8 +2381,10 @@ int lookup_module_symbol_attrs(unsigned
preempt_disable();
list_for_each_entry(mod, &modules, list) {
- if (within(addr, mod->module_init, mod->init_size) ||
- within(addr, mod->module_core, mod->core_size)) {
+ if (addr_within_len((void *) addr, mod->module_init,
+ mod->init_size) ||
+ addr_within_len((void *) addr, mod->module_core,
+ mod->core_size)) {
const char *sym;
sym = get_ksymbol(mod, addr, size, offset);
@@ -2579,7 +2580,8 @@ int is_module_address(unsigned long addr
preempt_disable();
list_for_each_entry(mod, &modules, list) {
- if (within(addr, mod->module_core, mod->core_size)) {
+ if (addr_within_len((void *) addr, mod->module_core,
+ mod->core_size)) {
preempt_enable();
return 1;
}
@@ -2597,8 +2599,10 @@ struct module *__module_text_address(uns
struct module *mod;
list_for_each_entry(mod, &modules, list)
- if (within(addr, mod->module_init, mod->init_text_size)
- || within(addr, mod->module_core, mod->core_text_size))
+ if (addr_within_len((void *) addr, mod->module_init,
+ mod->init_text_size)
+ || addr_within_len((void *) addr, mod->module_core,
+ mod->core_text_size))
return mod;
return NULL;
}
Index: linux-2.6.26-rc3/arch/x86/mm/pageattr.c
===================================================================
--- linux-2.6.26-rc3.orig/arch/x86/mm/pageattr.c
+++ linux-2.6.26-rc3/arch/x86/mm/pageattr.c
@@ -2,6 +2,7 @@
* Copyright 2002 Andi Kleen, SuSE Labs.
* Thanks to Ben LaHaise for precious feedback.
*/
+#include <linux/kernel.h>
#include <linux/highmem.h>
#include <linux/bootmem.h>
#include <linux/module.h>
@@ -54,12 +55,6 @@ static inline unsigned long highmap_end_
# define debug_pagealloc 0
#endif
-static inline int
-within(unsigned long addr, unsigned long start, unsigned long end)
-{
- return addr >= start && addr < end;
-}
-
/*
* Flushing functions
*/
@@ -164,7 +159,8 @@ static inline pgprot_t static_protection
* The BIOS area between 640k and 1Mb needs to be executable for
* PCI BIOS based config access (CONFIG_PCI_GOBIOS) support.
*/
- if (within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
+ if (addr_within((void *) pfn, (void *) (BIOS_BEGIN >> PAGE_SHIFT),
+ (void *) (BIOS_END >> PAGE_SHIFT)))
pgprot_val(forbidden) |= _PAGE_NX;
/*
@@ -172,15 +168,16 @@ static inline pgprot_t static_protection
* Does not cover __inittext since that is gone later on. On
* 64bit we do not enforce !NX on the low mapping
*/
- if (within(address, (unsigned long)_text, (unsigned long)_etext))
+ if (addr_within((void *) address, _text, _etext))
pgprot_val(forbidden) |= _PAGE_NX;
/*
* The .rodata section needs to be read-only. Using the pfn
* catches all aliases.
*/
- if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
- __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
+ if (addr_within((void *) pfn,
+ (void *) (__pa(__start_rodata) >> PAGE_SHIFT),
+ (void *) (__pa(__end_rodata) >> PAGE_SHIFT)))
pgprot_val(forbidden) |= _PAGE_RW;
prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
@@ -620,8 +617,8 @@ static int cpa_process_alias(struct cpa_
* No need to redo, when the primary call touched the direct
* mapping already:
*/
- if (!within(cpa->vaddr, PAGE_OFFSET,
- PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))) {
+ if (!addr_within((void *) cpa->vaddr, (void *) PAGE_OFFSET,
+ (void *) (PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT)))) {
alias_cpa = *cpa;
alias_cpa.vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT);
@@ -636,14 +633,15 @@ static int cpa_process_alias(struct cpa_
* No need to redo, when the primary call touched the high
* mapping already:
*/
- if (within(cpa->vaddr, (unsigned long) _text, (unsigned long) _end))
+ if (addr_within((void *) cpa->vaddr, _text, _end))
return 0;
/*
* If the physical address is inside the kernel map, we need
* to touch the high mapped kernel as well:
*/
- if (!within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn()))
+ if (!addr_within((void *) cpa->pfn, (void *) highmap_start_pfn(),
+ (void *) highmap_end_pfn()))
return 0;
alias_cpa = *cpa;
--
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