Commit d790be38 authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "The exciting thing here is the getting rid of stop_machine on module
  removal.  This is possible by using a simple atomic_t for the counter,
  rather than our fancy per-cpu counter: it turns out that no one is
  doing a module increment per net packet, so the slowdown should be in
  the noise"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  param: do not set store func without write perm
  params: cleanup sysfs allocation
  kernel:module Fix coding style errors and warnings.
  module: Remove stop_machine from module unloading
  module: Replace module_ref with atomic_t refcnt
  lib/bug: Use RCU list ops for module_bug_list
  module: Unlink module with RCU synchronizing instead of stop_machine
  module: Wait for RCU synchronizing before releasing a module
parents 64ec45bf b0a65b0c
......@@ -210,20 +210,6 @@ enum module_state {
MODULE_STATE_UNFORMED, /* Still setting it up. */
};
/**
* 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;
......@@ -367,7 +353,7 @@ struct module {
/* Destruction function. */
void (*exit)(void);
struct module_ref __percpu *refptr;
atomic_t refcnt;
#endif
#ifdef CONFIG_CONSTRUCTORS
......
......@@ -80,7 +80,7 @@ DECLARE_EVENT_CLASS(module_refcnt,
TP_fast_assign(
__entry->ip = ip;
__entry->refcnt = __this_cpu_read(mod->refptr->incs) - __this_cpu_read(mod->refptr->decs);
__entry->refcnt = atomic_read(&mod->refcnt);
__assign_str(name, mod->name);
),
......
This diff is collapsed.
......@@ -603,73 +603,66 @@ static __modinit int add_sysfs_param(struct module_kobject *mk,
const struct kernel_param *kp,
const char *name)
{
struct module_param_attrs *new;
struct attribute **attrs;
int err, num;
struct module_param_attrs *new_mp;
struct attribute **new_attrs;
unsigned int i;
/* We don't bother calling this with invisible parameters. */
BUG_ON(!kp->perm);
if (!mk->mp) {
num = 0;
attrs = NULL;
} else {
num = mk->mp->num;
attrs = mk->mp->grp.attrs;
/* First allocation. */
mk->mp = kzalloc(sizeof(*mk->mp), GFP_KERNEL);
if (!mk->mp)
return -ENOMEM;
mk->mp->grp.name = "parameters";
/* NULL-terminated attribute array. */
mk->mp->grp.attrs = kzalloc(sizeof(mk->mp->grp.attrs[0]),
GFP_KERNEL);
/* Caller will cleanup via free_module_param_attrs */
if (!mk->mp->grp.attrs)
return -ENOMEM;
}
/* Enlarge. */
new = krealloc(mk->mp,
sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
/* Enlarge allocations. */
new_mp = krealloc(mk->mp,
sizeof(*mk->mp) +
sizeof(mk->mp->attrs[0]) * (mk->mp->num + 1),
GFP_KERNEL);
if (!new) {
kfree(attrs);
err = -ENOMEM;
goto fail;
}
/* Despite looking like the typical realloc() bug, this is safe.
* We *want* the old 'attrs' to be freed either way, and we'll store
* the new one in the success case. */
attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
if (!attrs) {
err = -ENOMEM;
goto fail_free_new;
}
if (!new_mp)
return -ENOMEM;
mk->mp = new_mp;
/* Sysfs wants everything zeroed. */
memset(new, 0, sizeof(*new));
memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
memset(&attrs[num], 0, sizeof(attrs[num]));
new->grp.name = "parameters";
new->grp.attrs = attrs;
/* Extra pointer for NULL terminator */
new_attrs = krealloc(mk->mp->grp.attrs,
sizeof(mk->mp->grp.attrs[0]) * (mk->mp->num + 2),
GFP_KERNEL);
if (!new_attrs)
return -ENOMEM;
mk->mp->grp.attrs = new_attrs;
/* Tack new one on the end. */
sysfs_attr_init(&new->attrs[num].mattr.attr);
new->attrs[num].param = kp;
new->attrs[num].mattr.show = param_attr_show;
new->attrs[num].mattr.store = param_attr_store;
new->attrs[num].mattr.attr.name = (char *)name;
new->attrs[num].mattr.attr.mode = kp->perm;
new->num = num+1;
sysfs_attr_init(&mk->mp->attrs[mk->mp->num].mattr.attr);
mk->mp->attrs[mk->mp->num].param = kp;
mk->mp->attrs[mk->mp->num].mattr.show = param_attr_show;
/* Do not allow runtime DAC changes to make param writable. */
if ((kp->perm & (S_IWUSR | S_IWGRP | S_IWOTH)) != 0)
mk->mp->attrs[mk->mp->num].mattr.store = param_attr_store;
mk->mp->attrs[mk->mp->num].mattr.attr.name = (char *)name;
mk->mp->attrs[mk->mp->num].mattr.attr.mode = kp->perm;
mk->mp->num++;
/* Fix up all the pointers, since krealloc can move us */
for (num = 0; num < new->num; num++)
new->grp.attrs[num] = &new->attrs[num].mattr.attr;
new->grp.attrs[num] = NULL;
mk->mp = new;
for (i = 0; i < mk->mp->num; i++)
mk->mp->grp.attrs[i] = &mk->mp->attrs[i].mattr.attr;
mk->mp->grp.attrs[mk->mp->num] = NULL;
return 0;
fail_free_new:
kfree(new);
fail:
mk->mp = NULL;
return err;
}
#ifdef CONFIG_MODULES
static void free_module_param_attrs(struct module_kobject *mk)
{
if (mk->mp)
kfree(mk->mp->grp.attrs);
kfree(mk->mp);
mk->mp = NULL;
......@@ -695,8 +688,10 @@ int module_param_sysfs_setup(struct module *mod,
if (kparam[i].perm == 0)
continue;
err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
if (err)
if (err) {
free_module_param_attrs(&mod->mkobj);
return err;
}
params = true;
}
......
......@@ -64,16 +64,22 @@ static LIST_HEAD(module_bug_list);
static const struct bug_entry *module_find_bug(unsigned long bugaddr)
{
struct module *mod;
const struct bug_entry *bug = NULL;
list_for_each_entry(mod, &module_bug_list, bug_list) {
const struct bug_entry *bug = mod->bug_table;
rcu_read_lock();
list_for_each_entry_rcu(mod, &module_bug_list, bug_list) {
unsigned i;
bug = mod->bug_table;
for (i = 0; i < mod->num_bugs; ++i, ++bug)
if (bugaddr == bug_addr(bug))
return bug;
goto out;
}
return NULL;
bug = NULL;
out:
rcu_read_unlock();
return bug;
}
void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
......@@ -99,13 +105,15 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
* Strictly speaking this should have a spinlock to protect against
* traversals, but since we only traverse on BUG()s, a spinlock
* could potentially lead to deadlock and thus be counter-productive.
* Thus, this uses RCU to safely manipulate the bug list, since BUG
* must run in non-interruptive state.
*/
list_add(&mod->bug_list, &module_bug_list);
list_add_rcu(&mod->bug_list, &module_bug_list);
}
void module_bug_cleanup(struct module *mod)
{
list_del(&mod->bug_list);
list_del_rcu(&mod->bug_list);
}
#else
......
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