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Merge branch 'linus' into tracing/core

Browse Source 
Conflicts:
	include/linux/module.h
	kernel/module.c

Semantic conflict:
	include/trace/events/module.h

Merge reason: Resolve the conflict with upstream commit 5fbfb18 ("Fix up
              possibly racy module refcounting")

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar
2010-04-08 09:06:12 +02:00
parent ff0ff84a07 f5284e7635
commit c1ab9cab75
4460 changed files with 23903 additions and 4384 deletions
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137
kernel/module.c
View File

@@ -368,27 +368,33 @@ EXPORT_SYMBOL_GPL(find_module);
#ifdef CONFIG_SMP
static void *percpu_modalloc(unsigned long size, unsigned long align,
const char *name)
static inline void __percpu *mod_percpu(struct module *mod)
{
void *ptr;
return mod->percpu;
}
static int percpu_modalloc(struct module *mod,
unsigned long size, unsigned long align)
{
if (align > PAGE_SIZE) {
printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
name, align, PAGE_SIZE);
mod->name, align, PAGE_SIZE);
align = PAGE_SIZE;
}
ptr = __alloc_reserved_percpu(size, align);
if (!ptr)
mod->percpu = __alloc_reserved_percpu(size, align);
if (!mod->percpu) {
printk(KERN_WARNING
"Could not allocate %lu bytes percpu data\n", size);
return ptr;
return -ENOMEM;
}
mod->percpu_size = size;
return 0;
}
static void percpu_modfree(void *freeme)
static void percpu_modfree(struct module *mod)
{
free_percpu(freeme);
free_percpu(mod->percpu);
}
static unsigned int find_pcpusec(Elf_Ehdr *hdr,
@@ -398,24 +404,62 @@ static unsigned int find_pcpusec(Elf_Ehdr *hdr,
return find_sec(hdr, sechdrs, secstrings, ".data.percpu");
}
static void percpu_modcopy(void *pcpudest, const void *from, unsigned long size)
static void percpu_modcopy(struct module *mod,
const void *from, unsigned long size)
{
int cpu;
for_each_possible_cpu(cpu)
memcpy(pcpudest + per_cpu_offset(cpu), from, size);
memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
}
/**
* is_module_percpu_address - test whether address is from module static percpu
* @addr: address to test
*
* Test whether @addr belongs to module static percpu area.
*
* RETURNS:
* %true if @addr is from module static percpu area
*/
bool is_module_percpu_address(unsigned long addr)
{
struct module *mod;
unsigned int cpu;
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (!mod->percpu_size)
continue;
for_each_possible_cpu(cpu) {
void *start = per_cpu_ptr(mod->percpu, cpu);
if ((void *)addr >= start &&
(void *)addr < start + mod->percpu_size) {
preempt_enable();
return true;
}
}
}
preempt_enable();
return false;
}
#else /* ... !CONFIG_SMP */
static inline void *percpu_modalloc(unsigned long size, unsigned long align,
const char *name)
static inline void __percpu *mod_percpu(struct module *mod)
{
return NULL;
}
static inline void percpu_modfree(void *pcpuptr)
static inline int percpu_modalloc(struct module *mod,
unsigned long size, unsigned long align)
{
return -ENOMEM;
}
static inline void percpu_modfree(struct module *mod)
{
BUG();
}
static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
@@ -423,12 +467,16 @@ static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
{
return 0;
}
static inline void percpu_modcopy(void *pcpudst, const void *src,
unsigned long size)
static inline void percpu_modcopy(struct module *mod,
const void *from, unsigned long size)
{
/* pcpusec should be 0, and size of that section should be 0. */
BUG_ON(size != 0);
}
bool is_module_percpu_address(unsigned long addr)
{
return false;
}
#endif /* CONFIG_SMP */
@@ -474,11 +522,13 @@ static void module_unload_init(struct module *mod)
int cpu;
INIT_LIST_HEAD(&mod->modules_which_use_me);
for_each_possible_cpu(cpu)
per_cpu_ptr(mod->refptr, cpu)->count = 0;
for_each_possible_cpu(cpu) {
per_cpu_ptr(mod->refptr, cpu)->incs = 0;
per_cpu_ptr(mod->refptr, cpu)->decs = 0;
}
/* Hold reference count during initialization. */
__this_cpu_write(mod->refptr->count, 1);
__this_cpu_write(mod->refptr->incs, 1);
/* Backwards compatibility macros put refcount during init. */
mod->waiter = current;
}
@@ -617,12 +667,28 @@ static int try_stop_module(struct module *mod, int flags, int *forced)
unsigned int module_refcount(struct module *mod)
{
unsigned int total = 0;
unsigned int incs = 0, decs = 0;
int cpu;
for_each_possible_cpu(cpu)
total += per_cpu_ptr(mod->refptr, cpu)->count;
return total;
decs += per_cpu_ptr(mod->refptr, cpu)->decs;
/*
* ensure the incs are added up after the decs.
* module_put ensures incs are visible before decs with smp_wmb.
*
* This 2-count scheme avoids the situation where the refcount
* for CPU0 is read, then CPU0 increments the module refcount,
* then CPU1 drops that refcount, then the refcount for CPU1 is
* read. We would record a decrement but not its corresponding
* increment so we would see a low count (disaster).
*
* Rare situation? But module_refcount can be preempted, and we
* might be tallying up 4096+ CPUs. So it is not impossible.
*/
smp_rmb();
for_each_possible_cpu(cpu)
incs += per_cpu_ptr(mod->refptr, cpu)->incs;
return incs - decs;
}
EXPORT_SYMBOL(module_refcount);
@@ -799,7 +865,8 @@ void module_put(struct module *module)
{
if (module) {
preempt_disable();
__this_cpu_dec(module->refptr->count);
smp_wmb(); /* see comment in module_refcount */
__this_cpu_inc(module->refptr->decs);
trace_module_put(module, _RET_IP_);
/* Maybe they're waiting for us to drop reference? */
@@ -1400,8 +1467,7 @@ static void free_module(struct module *mod)
/* This may be NULL, but that's OK */
module_free(mod, mod->module_init);
kfree(mod->args);
if (mod->percpu)
percpu_modfree(mod->percpu);
percpu_modfree(mod);
#if defined(CONFIG_MODULE_UNLOAD)
if (mod->refptr)
free_percpu(mod->refptr);
@@ -1520,7 +1586,7 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
default:
/* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == pcpuindex)
secbase = (unsigned long)mod->percpu;
secbase = (unsigned long)mod_percpu(mod);
else
secbase = sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
@@ -1954,7 +2020,7 @@ static noinline struct module *load_module(void __user *umod,
unsigned int modindex, versindex, infoindex, pcpuindex;
struct module *mod;
long err = 0;
void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
void *ptr = NULL; /* Stops spurious gcc warning */
unsigned long symoffs, stroffs, *strmap;
mm_segment_t old_fs;
@@ -2094,15 +2160,11 @@ static noinline struct module *load_module(void __user *umod,
if (pcpuindex) {
/* We have a special allocation for this section. */
percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size,
sechdrs[pcpuindex].sh_addralign,
mod->name);
if (!percpu) {
err = -ENOMEM;
err = percpu_modalloc(mod, sechdrs[pcpuindex].sh_size,
sechdrs[pcpuindex].sh_addralign);
if (err)
goto free_mod;
}
sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
mod->percpu = percpu;
}
/* Determine total sizes, and put offsets in sh_entsize. For now
@@ -2317,7 +2379,7 @@ static noinline struct module *load_module(void __user *umod,
sort_extable(mod->extable, mod->extable + mod->num_exentries);
/* Finally, copy percpu area over. */
percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr,
percpu_modcopy(mod, (void *)sechdrs[pcpuindex].sh_addr,
sechdrs[pcpuindex].sh_size);
add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex,
@@ -2409,8 +2471,7 @@ static noinline struct module *load_module(void __user *umod,
module_free(mod, mod->module_core);
/* mod will be freed with core. Don't access it beyond this line! */
free_percpu:
if (percpu)
percpu_modfree(percpu);
percpu_modfree(mod);
free_mod:
kfree(args);
kfree(strmap);