Messages in this thread Patch in this message | | | Date | Wed, 8 Feb 2017 15:48:01 +0100 | From | Peter Zijlstra <> | Subject | [PATCH] module: Optimize search_module_extables() |
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While looking through the __ex_table stuff I found that we do a linear lookup of the module. Also fix up a comment.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/module.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c index 3d8f126208e3..7bcdc35dbf95 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -4165,22 +4165,23 @@ const struct exception_table_entry *search_module_extables(unsigned long addr) struct module *mod; preempt_disable(); - list_for_each_entry_rcu(mod, &modules, list) { - if (mod->state == MODULE_STATE_UNFORMED) - continue; - if (mod->num_exentries == 0) - continue; + mod = __module_address(addr); + if (!mod) + goto out; - e = search_extable(mod->extable, - mod->extable + mod->num_exentries - 1, - addr); - if (e) - break; - } + if (!mod->num_exentries) + goto out; + + e = search_extable(mod->extable, + mod->extable + mod->num_exentries - 1, + addr); +out: preempt_enable(); - /* Now, if we found one, we are running inside it now, hence - we cannot unload the module, hence no refcnt needed. */ + /* + * Now, if we found one, we are running inside it now, hence + * we cannot unload the module, hence no refcnt needed. + */ return e; }
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