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driver core: Avoid deferred probe due to fw_devlink_pause/resume() 

With the earlier patch in this series, all devices that deferred probe
due to fw_devlink_pause() will have their probes delayed till the
deferred probe thread is kicked off during late_initcall. This will also
affect all their consumers.

This delayed probing in unnecessary. So this patch just keeps track of
the devices that had their probe deferred due to fw_devlink_pause() and
attempts to probe them once during fw_devlink_resume().

Fixes: 716a7a2596 ("driver core: fw_devlink: Add support for batching fwnode parsing")
Signed-off-by: Saravana Kannan <saravanak@google.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20200701194259.3337652-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
zero-sugar-mainline-defconfig
Saravana Kannan 2020-07-01 12:42:59 -07:00 committed by Greg Kroah-Hartman
parent ec7bd78498
commit 2451e74647
2 changed files with 23 additions and 1 deletions
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21
drivers/base/core.c
View File

@ -50,6 +50,7 @@ static DEFINE_MUTEX(wfs_lock);
static LIST_HEAD(deferred_sync);
static unsigned int defer_sync_state_count = 1;
static unsigned int defer_fw_devlink_count;
static LIST_HEAD(deferred_fw_devlink);
static DEFINE_MUTEX(defer_fw_devlink_lock);
static bool fw_devlink_is_permissive(void);
@ -1244,6 +1245,12 @@ static void fw_devlink_link_device(struct device *dev)
fw_ret = -EAGAIN;
} else {
fw_ret = -ENODEV;
/*
* defer_hook is not used to add device to deferred_sync list
* until device is bound. Since deferred fw devlink also blocks
* probing, same list hook can be used for deferred_fw_devlink.
*/
list_add_tail(&dev->links.defer_hook, &deferred_fw_devlink);
}
if (fw_ret == -ENODEV)
@ -1312,6 +1319,9 @@ void fw_devlink_pause(void)
*/
void fw_devlink_resume(void)
{
struct device *dev, *tmp;
LIST_HEAD(probe_list);
mutex_lock(&defer_fw_devlink_lock);
if (!defer_fw_devlink_count) {
WARN(true, "Unmatched fw_devlink pause/resume!");
@ -1323,8 +1333,19 @@ void fw_devlink_resume(void)
goto out;
device_link_add_missing_supplier_links();
list_splice_tail_init(&deferred_fw_devlink, &probe_list);
out:
mutex_unlock(&defer_fw_devlink_lock);
/*
* bus_probe_device() can cause new devices to get added and they'll
* try to grab defer_fw_devlink_lock. So, this needs to be done outside
* the defer_fw_devlink_lock.
*/
list_for_each_entry_safe(dev, tmp, &probe_list, links.defer_hook) {
list_del_init(&dev->links.defer_hook);
bus_probe_device(dev);
}
}
/* Device links support end. */

3
include/linux/device.h
View File

@ -433,7 +433,8 @@ enum dl_dev_state {
* @suppliers: List of links to supplier devices.
* @consumers: List of links to consumer devices.
* @needs_suppliers: Hook to global list of devices waiting for suppliers.
* @defer_hook: Hook to global list of devices that have deferred sync_state.
* @defer_hook: Hook to global list of devices that have deferred sync_state or
* deferred fw_devlink.
* @need_for_probe: If needs_suppliers is on a list, this indicates if the
* suppliers are needed for probe or not.
* @status: Driver status information.