From: Petr Mladek <pmladek@suse.com>
To: Jiri Kosina <jikos@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>
Cc: Joe Lawrence <joe.lawrence@redhat.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Nicolai Stange <nstange@suse.de>,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
Petr Mladek <pmladek@suse.com>
Subject: [POC 18/23] module: Refactor add_unformed_module()
Date: Fri, 17 Jan 2020 16:03:18 +0100 [thread overview]
Message-ID: <20200117150323.21801-19-pmladek@suse.com> (raw)
In-Reply-To: <20200117150323.21801-1-pmladek@suse.com>
The livepatching code will need to add another condition to avoid
waiting. Let's make the code slightly less hairy.
Of course, it is a matter of taste. The main ideas of refactoring:
+ Make it clear what happens when old->state == MODULE_STATE_LIVE.
+ Make it more clear when we are leaving the function immediately
and when we are doing some extra actions.
+ Be able to add another check that has to be done outside
module_mutex and can result into an immediate return.
Signed-off-by: Petr Mladek <pmladek@suse.com>
---
kernel/module.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index b3f11524f8f9..ac45d465ff23 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3721,28 +3721,30 @@ static int add_unformed_module(struct module *mod)
again:
mutex_lock(&module_mutex);
old = find_module_all(mod->name, strlen(mod->name), true);
+
if (old != NULL) {
- if (old->state != MODULE_STATE_LIVE) {
- /* Wait in case it fails to load. */
+ if (old->state == MODULE_STATE_LIVE) {
mutex_unlock(&module_mutex);
- err = wait_event_interruptible(module_wq,
- finished_loading(mod->name));
- if (err)
- goto out_unlocked;
- goto again;
+ return -EEXIST;
}
- err = -EEXIST;
- goto out;
+
+ /* Wait in case it fails to load. */
+ mutex_unlock(&module_mutex);
+ err = wait_event_interruptible(module_wq,
+ finished_loading(mod->name));
+ if (err)
+ return err;
+
+ /* Did the load succeded or failed? */
+ goto again;
}
+
mod_update_bounds(mod);
list_add_rcu(&mod->list, &modules);
mod_tree_insert(mod);
- err = 0;
-out:
mutex_unlock(&module_mutex);
-out_unlocked:
- return err;
+ return 0;
}
static int complete_formation(struct module *mod, struct load_info *info)
--
2.16.4
next prev parent reply other threads:[~2020-01-17 15:04 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-17 15:03 [POC 00/23] livepatch: Split livepatch module per-object Petr Mladek
2020-01-17 15:03 ` [POC 01/23] module: Allow to delete module also from inside kernel Petr Mladek
2020-01-21 11:11 ` Julien Thierry
2020-01-17 15:03 ` [POC 02/23] livepatch: Split livepatch modules per livepatched object Petr Mladek
2020-01-21 11:11 ` Julien Thierry
2020-01-28 12:16 ` Petr Mladek
2020-01-17 15:03 ` [POC 03/23] livepatch: Better checks of struct klp_object definition Petr Mladek
2020-01-21 11:27 ` Julien Thierry
2020-01-17 15:03 ` [POC 04/23] livepatch: Prevent loading livepatch sub-module unintentionally Petr Mladek
2020-04-03 17:54 ` Joe Lawrence
2020-01-17 15:03 ` [POC 05/23] livepatch: Initialize and free livepatch submodule Petr Mladek
2020-01-21 11:58 ` Julien Thierry
2020-01-17 15:03 ` [POC 06/23] livepatch: Enable the " Petr Mladek
2020-01-17 15:03 ` [POC 07/23] livepatch: Remove obsolete functionality from klp_module_coming() Petr Mladek
2020-01-17 15:03 ` [POC 08/23] livepatch: Automatically load livepatch module when the patch module is loaded Petr Mladek
2020-01-17 15:03 ` [POC 09/23] livepatch: Handle race when livepatches are reloaded during a module load Petr Mladek
2020-01-22 18:51 ` Julien Thierry
2020-01-17 15:03 ` [POC 10/23] livepatch: Handle modprobe exit code Petr Mladek
2020-01-17 15:03 ` [POC 11/23] livepatch: Safely detect forced transition when removing split livepatch modules Petr Mladek
2020-01-22 10:15 ` Julien Thierry
2020-01-17 15:03 ` [POC 12/23] livepatch: Automatically remove livepatch module when the object is freed Petr Mladek
2020-01-17 15:03 ` [POC 13/23] livepatch: Remove livepatch module when the livepatched module is unloaded Petr Mladek
2020-01-17 15:03 ` [POC 14/23] livepatch: Never block livepatch modules when the related module is being removed Petr Mladek
2020-01-17 15:03 ` [POC 15/23] livepatch: Prevent infinite loop when loading livepatch module Petr Mladek
2020-01-17 15:03 ` [POC 16/23] livepatch: Add patch into the global list early Petr Mladek
2020-01-17 15:03 ` [POC 17/23] livepatch: Load livepatches for modules when loading the main livepatch Petr Mladek
2020-01-17 15:03 ` Petr Mladek [this message]
2020-01-17 15:03 ` [POC 19/23] module/livepatch: Allow to use exported symbols from livepatch module for "vmlinux" Petr Mladek
2020-04-06 18:48 ` Joe Lawrence
2020-04-07 7:33 ` Miroslav Benes
2020-04-07 20:57 ` Joe Lawrence
2020-01-17 15:03 ` [POC 20/23] module/livepatch: Relocate local variables in the module loaded when the livepatch is being loaded Petr Mladek
2020-01-18 10:29 ` kbuild test robot
2020-04-03 18:00 ` Joe Lawrence
2020-01-17 15:03 ` [POC 21/23] livepatch: Remove obsolete arch_klp_init_object_loaded() Petr Mladek
2020-01-17 15:03 ` [POC 22/23] livepatch/module: Remove obsolete copy_module_elf() Petr Mladek
2020-04-03 18:03 ` Joe Lawrence
2020-01-17 15:03 ` [POC 23/23] module: Remove obsolete module_disable_ro() Petr Mladek
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