lkml.org 
[lkml]   [2017]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] module: Optimize search_module_extables()

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;
}

\
 
 \ /
  Last update: 2017-02-08 16:57    [W:0.050 / U:1.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site