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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
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5
include/linux/module.h
View File

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

66
kernel/module.c
View File

@ -370,27 +370,33 @@ EXPORT_SYMBOL_GPL(find_module);
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
static void *percpu_modalloc(unsigned long size, unsigned long align, static inline void __percpu *mod_percpu(struct module *mod)
const char *name)
{ {
void *ptr; return mod->percpu;
}
static int percpu_modalloc(struct module *mod,
unsigned long size, unsigned long align)
{
if (align > PAGE_SIZE) { if (align > PAGE_SIZE) {
printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n", printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
name, align, PAGE_SIZE); mod->name, align, PAGE_SIZE);
align = PAGE_SIZE; align = PAGE_SIZE;
} }
ptr = __alloc_reserved_percpu(size, align); mod->percpu = __alloc_reserved_percpu(size, align);
if (!ptr) if (!mod->percpu) {
printk(KERN_WARNING printk(KERN_WARNING
"Could not allocate %lu bytes percpu data\n", size); "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, 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"); 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; int cpu;
for_each_possible_cpu(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 */ #else /* ... !CONFIG_SMP */
static inline void *percpu_modalloc(unsigned long size, unsigned long align, static inline void __percpu *mod_percpu(struct module *mod)
const char *name)
{ {
return NULL; 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, static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs, Elf_Shdr *sechdrs,
@ -425,8 +435,8 @@ static inline unsigned int find_pcpusec(Elf_Ehdr *hdr,
{ {
return 0; return 0;
} }
static inline void percpu_modcopy(void *pcpudst, const void *src, static inline void percpu_modcopy(struct module *mod,
unsigned long size) const void *from, unsigned long size)
{ {
/* pcpusec should be 0, and size of that section should be 0. */ /* pcpusec should be 0, and size of that section should be 0. */
BUG_ON(size != 0); BUG_ON(size != 0);
@ -1400,8 +1410,7 @@ static void free_module(struct module *mod)
/* This may be NULL, but that's OK */ /* This may be NULL, but that's OK */
module_free(mod, mod->module_init); module_free(mod, mod->module_init);
kfree(mod->args); kfree(mod->args);
if (mod->percpu) percpu_modfree(mod);
percpu_modfree(mod->percpu);
#if defined(CONFIG_MODULE_UNLOAD) #if defined(CONFIG_MODULE_UNLOAD)
if (mod->refptr) if (mod->refptr)
free_percpu(mod->refptr); free_percpu(mod->refptr);
@ -1520,7 +1529,7 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
default: default:
/* Divert to percpu allocation if a percpu var. */ /* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == pcpuindex) if (sym[i].st_shndx == pcpuindex)
secbase = (unsigned long)mod->percpu; secbase = (unsigned long)mod_percpu(mod);
else else
secbase = sechdrs[sym[i].st_shndx].sh_addr; secbase = sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase; sym[i].st_value += secbase;
@ -1954,7 +1963,7 @@ static noinline struct module *load_module(void __user *umod,
unsigned int modindex, versindex, infoindex, pcpuindex; unsigned int modindex, versindex, infoindex, pcpuindex;
struct module *mod; struct module *mod;
long err = 0; long err = 0;
void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ void *ptr = NULL; /* Stops spurious gcc warning */
unsigned long symoffs, stroffs, *strmap; unsigned long symoffs, stroffs, *strmap;
mm_segment_t old_fs; mm_segment_t old_fs;
@ -2094,15 +2103,11 @@ static noinline struct module *load_module(void __user *umod,
if (pcpuindex) { if (pcpuindex) {
/* We have a special allocation for this section. */ /* We have a special allocation for this section. */
percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size, err = percpu_modalloc(mod, sechdrs[pcpuindex].sh_size,
sechdrs[pcpuindex].sh_addralign, sechdrs[pcpuindex].sh_addralign);
mod->name); if (err)
if (!percpu) {
err = -ENOMEM;
goto free_mod; goto free_mod;
}
sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC; sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
mod->percpu = percpu;
} }
/* Determine total sizes, and put offsets in sh_entsize. For now /* 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); sort_extable(mod->extable, mod->extable + mod->num_exentries);
/* Finally, copy percpu area over. */ /* 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); sechdrs[pcpuindex].sh_size);
add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex, 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); module_free(mod, mod->module_core);
/* mod will be freed with core. Don't access it beyond this line! */ /* mod will be freed with core. Don't access it beyond this line! */
free_percpu: free_percpu:
if (percpu) percpu_modfree(mod);
percpu_modfree(percpu);
free_mod: free_mod:
kfree(args); kfree(args);
kfree(strmap); kfree(strmap);