linux-kernel - Re: [PATCH v3] zram: don't free statically defined names

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Message-ID: <20240924014632.GI38742@google.com>
Date: Tue, 24 Sep 2024 10:46:32 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc: Andrey Skvortsov <andrej.skvortzov@...il.com>,
	Venkat Rao Bagalkote <venkat88@...ux.vnet.ibm.com>,
	Minchan Kim <minchan@...nel.org>,
	Sergey Senozhatsky <senozhatsky@...omium.org>,
	Jens Axboe <axboe@...nel.dk>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH v3] zram: don't free statically defined names

On (24/09/23 19:40), Christophe JAILLET wrote:
[..]
> > +++ b/drivers/block/zram/zram_drv.c
> > @@ -2115,8 +2115,10 @@ static void zram_destroy_comps(struct zram *zram)
> >   		zram->num_active_comps--;
> >   	}
> > -	for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> > -		kfree(zram->comp_algs[prio]);
> > +	for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
> > +		/* Do not free statically defined compression algorithms */
> > +		if (zram->comp_algs[prio] != default_compressor)
> > +			kfree(zram->comp_algs[prio]);
> 
> Hi,
> 
> maybe kfree_const() to be more future proof and less verbose?

I didn't know about kfree_const().  If we change ->comp_algs release
to kfree_const(), then I'd probably prefer it to be a separate patch
that changes both zram_destroy_comps() and comp_algorithm_set().  The
current patch works for the way it is, given that it fixes a nasty
problem.