Re: [PATCH] zram: don't free statically defined names
From: Andrey Skvortsov
Date: Mon Sep 23 2024 - 12:43:42 EST
On 24-09-24 01:07, Sergey Senozhatsky wrote:
> On (24/09/23 18:55), Andrey Skvortsov wrote:
> [..]
> > > Ugh, I know what's happening. You don't have CONFIG_ZRAM_MULTI_COMP
> > > so that ZRAM_PRIMARY_COMP and ZRAM_SECONDARY_COMP are the same thing.
> > > Yeah, that all makes sense now, I haven't thought about it.
> >
> > yes, I don't have CONFIG_ZRAM_MULTI_COMP set. I'll include your
> > comment into commit description for v2.
>
> Thanks.
>
> Can you do it something like the diff below? Let's iterate
> ->comp_algs from ZRAM_PRIMARY_COMP. I don't really mind the
> "Do not free statically defined" comment, up to you.
>
> And the commit message probably can stay that: on !CONFIG_ZRAM_MULTI_COMP
> systems ZRAM_SECONDARY_COMP can hold default_compressor, because it's
> the same offset as ZRAM_PRIMARY_COMP, so we need to make sure that we
> don't attempt to kfree() the statically defined comp name.
>
> ---
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index c3d245617083..ad9c9bc3ccfc 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ 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]);
> zram->comp_algs[prio] = NULL;
> }
Sorry, I've seen you comment after I've sent v2. I'll do this in v3.
--
Best regards,
Andrey Skvortsov