linux-kernel - Re: [PATCH v9 1/7] nvmem: core: Create all cells before adding the nvmem device

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Message-ID: <20230811143821.29cf335a@xps-13>
Date:   Fri, 11 Aug 2023 14:38:21 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Robert Marko <robert.marko@...tura.hr>,
        Luka Perkov <luka.perkov@...tura.hr>,
        Michael Walle <michael@...le.cc>, linux-kernel@...r.kernel.org,
        Randy Dunlap <rdunlap@...radead.org>,
        Chen-Yu Tsai <wenst@...omium.org>,
        Daniel Golle <daniel@...rotopia.org>,
        Rafał Miłecki <rafal@...ecki.pl>
Subject: Re: [PATCH v9 1/7] nvmem: core: Create all cells before adding the
 nvmem device

Hi Srinivas,

srinivas.kandagatla@...aro.org wrote on Fri, 11 Aug 2023 13:26:24 +0100:

> On 11/08/2023 13:11, Miquel Raynal wrote:
> 
> >>
> >>  
> > 
> > nvmem_register() calls device_initialize() and later device_add(),
> > which is exactly the content of device_register(). Upon error
> > after device_add(), we currently call device_put(), whereas
> > device_unregister would call both device_del() and device_put().
> > 
> > I would expect device_del() to be first called upon error before
> > device_put() *after* device_add() has succeded, no?  
> 
> That is correct afaiu, if device_add is succeed we need to call device_del(). As the patch now moved the device_add to end of function we really do not need device_del() in err path.

Right, I'm looking at the end of the series where I need to add
device_del() in the error path because something gets added after
device_add(). So we are aligned, thanks for the feedback.

> >>> I also see the layout_np below should be freed before jumping in the
> >>> error section.  
> >>
> >> you mean missing of_node_put()?  
> > 
> > Yes, I need to call of_node_put() before jumping into the error path.  
> 
> Are we not already doing it in nvmem_layout_get() and nvmem_add_cells_from_fixed_layout() ?

We perform the layout_get for two reasons:
- knowing if there is a layout
- using the layout
Here we are in the first case, and we don't want to retain a reference
from here. Only in the second case.

Thanks,
Miquèl