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Commit 259354de authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent b72c4094

include/linux/module.h

+4 −1
Original line number Diff line number Diff line
@@ -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 */

kernel/module.c

+35 −31
Original line number Diff line number Diff line
@@ -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);