Messages in this thread | | | Date | Wed, 27 Sep 2023 10:08:21 +0200 | From | Greg KH <> | Subject | Re: [RESEND PATCH] driver core: Clear FWNODE_FLAG_LINKS_ADDED in device_links_purge() |
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On Wed, Sep 27, 2023 at 02:32:25PM +0800, Zhenhua Huang wrote: > > > On 2023/9/27 13:57, Greg KH wrote: > > On Wed, Sep 27, 2023 at 10:30:10AM +0800, Zhenhua Huang wrote: > > > Flag FWNODE_FLAG_LINKS_ADDED stops fwnode links creation. Current kernel > > > only adds it once after fwnode links creation in fw_devlink_parse_fwnode(). > > > After that even device links being purged, the flag will not be cleared. > > > > > > Fwnode links are converted to device links and will not be added back > > > forever in normal case. Essentially if a device is registered and > > > unregisted (also deleted) before it is probed (due to missing fwlink > > > dependencies, abort in device_links_check_suppliers), the fwlink is not > > > setup next when device is newly created again. This means the probe gets > > > called without meeting all dependencies. > > > > > > It usuallly happens in the case of a glue driver. Of_platform_populate() > > > allows us to populate subnodes. We may do it in ancestor node probing > > > function, then check subnode's probing status because there may be chances > > > that suppliers of subnode are not ready. We may further need to do > > > of_platform_depopulate(which purges device links) and in some time > > > of_platform_populate() again. Such case we miss fwnode links(so that device > > > links) during second time of populating subnodes. > > > > > > Fix it by Clearing FWNODE_FLAG_LINKS_ADDED flag in purging device link > > > func, indicates both fwnode links and device links are absent. > > > > > > Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com> > > > --- > > > drivers/base/core.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/drivers/base/core.c b/drivers/base/core.c > > > index b7d7f41..2a1975d 100644 > > > --- a/drivers/base/core.c > > > +++ b/drivers/base/core.c > > > @@ -1630,6 +1630,10 @@ static void device_links_purge(struct device *dev) > > > __device_link_del(&link->kref); > > > } > > > + /* Clear flags in fwnode. Give a chance to create fwnode link again */ > > > + if (dev->fwnode) > > > + dev->fwnode->flags &= ~FWNODE_FLAG_LINKS_ADDED; > > > + > > > device_links_write_unlock(); > > > } > > > -- > > > 2.7.4 > > > > > > > What commit id does this fix? > > This commit c2c724c868c4("driver core: Add fw_devlink_parse_fwtree()"). > Changelog mentioned: > "This function also ensures that no fwnode is parsed more than once by > marking the fwnodes as parsed."
Then is a Fixes: tag needed?
thanks,
greg k-h
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