linux-kernel - zram: zram_free_page calls in zram_meta

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Message-ID: <ebd87e1e-f941-498a-870e-15743ca3fb1f@linux.dev>
Date:   Mon, 6 Nov 2023 23:42:31 +0300
From:   Vasily Averin <vasily.averin@...ux.dev>
To:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        Minchan Kim <minchan@...nel.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-block@...r.kernel.org
Subject: zram: zram_free_page calls in zram_meta_free

The only place where content of zram entry is accessed and even changed without taken zran lock is
zram_free_page() calls from zram_meta_free().

It does not look like problem because zram should not have any users at this point,
however I still do not understand why this is required?

Is it performance optimization? But zram reset is quite rare operation, I doubt it is called
on some performance-critical fast path. Am I missed something perhaps?

I would like to add proper zram_lock/unlock calls around zram_free_page here,
and would like to clarify,perhaps you have any objections?

Thank you,
	Vasily Averin