linux-kernel - Re: [PATCH v2 08/24] EDAC: Introduce mci_for_each

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Message-ID: <20190828081849.xwbfgro6dfrrtdac@rric.localdomain>
Date:   Wed, 28 Aug 2019 08:18:56 +0000
From:   Robert Richter <rrichter@...vell.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     James Morse <james.morse@....com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 08/24] EDAC: Introduce mci_for_each_dimm() iterator

On 14.08.19 17:18:24, Borislav Petkov wrote:
> On Mon, Jun 24, 2019 at 03:09:11PM +0000, Robert Richter wrote:
> > Make code more readable by introducing a mci_for_each_dimm() iterator.
> > Now, we just get a pointer to a struct dimm_info. Direct array access
> > using an index is no longer needed to iterate.
> > 
> > Signed-off-by: Robert Richter <rrichter@...vell.com>
> > ---
> >  drivers/edac/edac_mc.c       | 18 ++++++++++--------
> >  drivers/edac/edac_mc_sysfs.c | 34 +++++++++++++++-------------------
> >  drivers/edac/ghes_edac.c     |  8 ++++----
> >  drivers/edac/i5100_edac.c    | 11 +++++------
> >  include/linux/edac.h         |  7 +++++++
> >  5 files changed, 41 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
> > index c44bc83e8502..27277ca46ab3 100644
> > --- a/drivers/edac/edac_mc.c
> > +++ b/drivers/edac/edac_mc.c
> > @@ -145,15 +145,18 @@ static void edac_mc_dump_channel(struct rank_info *chan)
> >  	edac_dbg(4, "    channel->dimm = %p\n", chan->dimm);
> >  }
> >  
> > -static void edac_mc_dump_dimm(struct dimm_info *dimm, int number)
> > +static void edac_mc_dump_dimm(struct dimm_info *dimm)
> >  {
> >  	char location[80];
> >  
> > +	if (!dimm->nr_pages)
> > +		return;
> > +
> 
> What's that for?

This is moved from the iterator loop below to here. It limits the dump
to only populated dimm slots.

> 
> >  	edac_dimm_info_location(dimm, location, sizeof(location));
> >  
> >  	edac_dbg(4, "%s%i: %smapped as virtual row %d, chan %d\n",
> >  		 dimm->mci->csbased ? "rank" : "dimm",
> > -		 number, location, dimm->csrow, dimm->cschannel);
> > +		 dimm->idx, location, dimm->csrow, dimm->cschannel);
> >  	edac_dbg(4, "  dimm = %p\n", dimm);
> >  	edac_dbg(4, "  dimm->label = '%s'\n", dimm->label);
> >  	edac_dbg(4, "  dimm->nr_pages = 0x%x\n", dimm->nr_pages);

> > diff --git a/drivers/edac/i5100_edac.c b/drivers/edac/i5100_edac.c
> > index 39ba7f2414ae..7ec42b26a716 100644
> > --- a/drivers/edac/i5100_edac.c
> > +++ b/drivers/edac/i5100_edac.c
> > @@ -846,14 +846,13 @@ static void i5100_init_interleaving(struct pci_dev *pdev,
> >  
> >  static void i5100_init_csrows(struct mem_ctl_info *mci)
> >  {
> > -	int i;
> >  	struct i5100_priv *priv = mci->pvt_info;
> > +	struct dimm_info *dimm;
> >  
> > -	for (i = 0; i < mci->tot_dimms; i++) {
> > -		struct dimm_info *dimm;
> > -		const unsigned long npages = i5100_npages(mci, i);
> > -		const unsigned chan = i5100_csrow_to_chan(mci, i);
> > -		const unsigned rank = i5100_csrow_to_rank(mci, i);
> > +	mci_for_each_dimm(mci, dimm) {
> > +		const unsigned long npages = i5100_npages(mci, dimm->idx);
> > +		const unsigned chan = i5100_csrow_to_chan(mci, dimm->idx);
> > +		const unsigned rank = i5100_csrow_to_rank(mci, dimm->idx);
> >  
> >  		if (!npages)
> >  			continue;
> 
> This cannot be right: the code here under this does now:
> 
> 	dimm = edac_get_dimm(mci, chan, rank, 0);
> 
> but dimm is already set. It used to get the DIMM using chan and rank but
> now you're iterating over the already initialized pointers. So I think
> you don't need the edac_get_dimm() anymore.

Right, it should calculate to the same pointer we already have and can
be removed. Good catch.

> 
> Also fix those up too, while at it pls:
> 
> WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
> #235: FILE: drivers/edac/i5100_edac.c:854:
> +               const unsigned chan = i5100_csrow_to_chan(mci, dimm->idx);
> 
> WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
> #236: FILE: drivers/edac/i5100_edac.c:855:
> +               const unsigned rank = i5100_csrow_to_rank(mci, dimm->idx);

I am going to fix this is a separate patch, though I will exclude
rework of struct i5100_priv.

I have reworked the patch according to all your other comments.

Thanks for review.

-Robert