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module: encapsulate percpu handling better and record percpu_size 

Better encapsulate module static percpu area handling so that code
outsidef of CONFIG_SMP ifdef doesn't deal with mod->percpu directly
and add mod->percpu_size and record percpu_size in it.  Both percpu
fields are compiled out on UP.  While at it, mark mod->percpu w/
__percpu.

This is to prepare for is_module_percpu_address().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Tejun Heo 2010-03-10 18:56:10 +09:00
parent b72c40949b
commit 259354deaa
2 changed files with 39 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/module.h
View File

@ -330,8 +330,11 @@ struct module
struct module_notes_attrs *notes_attrs;
#endif
#ifdef CONFIG_SMP
/* Per-cpu data. */
void *percpu;
void __percpu *percpu;
unsigned int percpu_size;
#endif
/* The command line arguments (may be mangled). People like
keeping pointers to this stuff */

66
kernel/module.c
View File

@ -370,27 +370,33 @@ 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,
@ -400,24 +406,28 @@ 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);
}
#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,
@ -425,8 +435,8 @@ 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);
@ -1400,8 +1410,7 @@ 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 +1529,7 @@ 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 +1963,7 @@ 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 +2103,11 @@ 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 +2322,7 @@ 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 +2414,7 @@ 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);