Hi,
I have prepared a patch that makes request_firmware skip the usual
grace period that it gives firmware images to show up, if it determines
that userspace was not notified at all.
When request_firmware is called, it sends an event to userspace to
ask for the firmware image that is needed, and then it installs a
timeout so that it will not wait forever for the image. However,
if userspace did not receive the event at all (no /sbin/hotplug,
for instance), then having the kernel wait is pointless. This is
particularly true during boot, when the wait is done synchronously
and the whole kernel freezes for a minute.
The attached patch fixes this by making _request_firmware check whether
the firmware loading event was succesfully sent to userspace, and skip
the timeout if it has not. The patch comes in two parts:
1. The first part changes kobject_uevent_env in lib/kobject_uevent.c
to report a failure if both netlink_broadcast (if applicable) and
call_usermodehelper fail to send the event to userspace. Nothing in
the kernel seems to care about the return value of kobject_uevent_env,
so this should not break anything.
2. The second part changes _request_firmware in
drivers/base/firmware_class.c to actually check the return value of
kobject_uevent and skip the loading_timeout delay if the loading event
was not delivered to userspace at all.
The patches apply cleanly against 2.6.23-rc1. Any suggestions or feedback
will be welcome.
Javier
PS Please CC: me on replies, as I am not subscribed to the list.
==========
From: Javier Pello <[email protected]>
kobject_uevent: return an error if event was not delivered to userspace
Make kobject_uevent_env return an error to the caller if the event was
not delivered to userspace either via netlink or via uevent_helper.
Signed-off-by: Javier Pello <[email protected]>
---
diff -u linux-2.6.22/lib/kobject_uevent.c linux-2.6.22-p/lib/kobject_uevent.c
--- linux-2.6.22/lib/kobject_uevent.c 2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22-p/lib/kobject_uevent.c 2007-07-18 20:17:10.000000000 +0200
@@ -186,7 +186,8 @@
}
NETLINK_CB(skb).dst_group = 1;
- netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL);
+ retval = netlink_broadcast(uevent_sock, skb, 0, 1,
+ GFP_KERNEL);
}
}
#endif
@@ -198,7 +199,18 @@
argv [0] = uevent_helper;
argv [1] = (char *)subsystem;
argv [2] = NULL;
- call_usermodehelper (argv[0], argv, envp, UMH_WAIT_EXEC);
+#if defined(CONFIG_NET)
+ if (retval) {
+ retval = call_usermodehelper (argv[0], argv, envp,
+ UMH_WAIT_EXEC);
+ } else {
+ call_usermodehelper (argv[0], argv, envp,
+ UMH_WAIT_EXEC);
+ }
+#else
+ retval = call_usermodehelper (argv[0], argv, envp,
+ UMH_WAIT_EXEC);
+#endif
}
exit:
==========
From: Javier Pello <[email protected]>
request_firmware: skip timeout if userspace was not notified
Stop _request_firmware from setting up a timer and waiting for
the firmware image to appear if kobject_uevent returns an error
(meaning userspace was not notified at all).
This prevents useless delays if there is no userspace tool to
provide the firmware image (eg during boot).
Signed-off-by: Javier Pello <[email protected]>
---
diff -u linux-2.6.22/drivers/base/firmware_class.c linux-2.6.22-p/drivers/base/firmware_class.c
--- linux-2.6.22/drivers/base/firmware_class.c 2007-07-09 01:32:17.000000000 +0200
+++ linux-2.6.22-p/drivers/base/firmware_class.c 2007-07-18 20:06:53.000000000 +0200
@@ -420,8 +420,12 @@
add_timer(&fw_priv->timeout);
}
- kobject_uevent(&f_dev->kobj, KOBJ_ADD);
- wait_for_completion(&fw_priv->completion);
+ retval = kobject_uevent(&f_dev->kobj, KOBJ_ADD);
+ if (retval) {
+ fw_load_abort(fw_priv);
+ } else {
+ wait_for_completion(&fw_priv->completion);
+ }
set_bit(FW_STATUS_DONE, &fw_priv->status);
del_timer_sync(&fw_priv->timeout);
} else
==========
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