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Commit bd77c047 authored by Eric Dumazet's avatar Eric Dumazet Committed by Rusty Russell
Browse files

module: struct module_ref should contains long fields 



module_ref contains two "unsigned int" fields.

Thats now too small, since some machines can open more than 2^32 files.

Check commit 518de9b3 (fs: allow for more than 2^31 files) for
reference.

We can add an aligned(2 * sizeof(unsigned long)) attribute to force
alloc_percpu() allocating module_ref areas in single cache lines.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Tejun Heo <tj@kernel.org>
CC: Robin Holt <holt@sgi.com>
CC: David Miller <davem@davemloft.net>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 48fd1188

include/linux/module.h

+16 −5
Original line number Diff line number Diff line
@@ -205,6 +205,20 @@ enum module_state 
	MODULE_STATE_GOING,

};



/**

 * struct module_ref - per cpu module reference counts

 * @incs: number of module get on this cpu

 * @decs: number of module put on this cpu

 *

 * We force an alignment on 8 or 16 bytes, so that alloc_percpu()

 * put @incs/@decs in same cache line, with no extra memory cost,

 * since alloc_percpu() is fine grained.

 */

struct module_ref {

	unsigned long incs;

	unsigned long decs;

} __attribute((aligned(2 * sizeof(unsigned long))));



struct module

{

	enum module_state state;
@@ -347,10 +361,7 @@ struct module 
	/* Destruction function. */

	void (*exit)(void);



	struct module_ref {

		unsigned int incs;

		unsigned int decs;

	} __percpu *refptr;

	struct module_ref __percpu *refptr;

#endif



#ifdef CONFIG_CONSTRUCTORS
@@ -434,7 +445,7 @@ extern void __module_put_and_exit(struct module *mod, long code) 
#define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);



#ifdef CONFIG_MODULE_UNLOAD

unsigned int module_refcount(struct module *mod);

unsigned long module_refcount(struct module *mod);

void __symbol_put(const char *symbol);

#define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x)

void symbol_put_addr(void *addr);

kernel/debug/kdb/kdb_main.c

+1 −1
Original line number Diff line number Diff line
@@ -1982,7 +1982,7 @@ static int kdb_lsmod(int argc, const char **argv) 
		kdb_printf("%-20s%8u  0x%p ", mod->name,

			   mod->core_size, (void *)mod);

#ifdef CONFIG_MODULE_UNLOAD

		kdb_printf("%4d ", module_refcount(mod));

		kdb_printf("%4ld ", module_refcount(mod));

#endif

		if (mod->state == MODULE_STATE_GOING)

			kdb_printf(" (Unloading)");

kernel/module.c

+4 −4
Original line number Diff line number Diff line
@@ -725,9 +725,9 @@ static int try_stop_module(struct module *mod, int flags, int *forced) 
	}

}



unsigned int module_refcount(struct module *mod)

unsigned long module_refcount(struct module *mod)

{

	unsigned int incs = 0, decs = 0;

	unsigned long incs = 0, decs = 0;

	int cpu;



	for_each_possible_cpu(cpu)
@@ -853,7 +853,7 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod) 
	struct module_use *use;

	int printed_something = 0;



	seq_printf(m, " %u ", module_refcount(mod));

	seq_printf(m, " %lu ", module_refcount(mod));



	/* Always include a trailing , so userspace can differentiate

           between this and the old multi-field proc format. */
@@ -903,7 +903,7 @@ EXPORT_SYMBOL_GPL(symbol_put_addr); 
static ssize_t show_refcnt(struct module_attribute *mattr,

			   struct module_kobject *mk, char *buffer)

{

	return sprintf(buffer, "%u\n", module_refcount(mk->mod));

	return sprintf(buffer, "%lu\n", module_refcount(mk->mod));

}



static struct module_attribute refcnt = {