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Wed, 11 Mar 2026 01:27:58 -0700 (PDT) Received: from google.com ([2a00:79e0:2031:6:93a4:8281:fe98:426a]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35a02e19708sm1947257a91.3.2026.03.11.01.27.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Mar 2026 01:27:57 -0700 (PDT) Date: Wed, 11 Mar 2026 17:27:54 +0900 From: Sergey Senozhatsky To: Andrew Morton Cc: Minchan Kim , Brian Geffon , linux-block@vger.kernel.org, linux-mm@kvack.org, gao xu , Sergey Senozhatsky Subject: Re: [PATCH] zram: do not permit params change after init Message-ID: References: <20260310060407.1133800-1-senozhatsky@chromium.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260310060407.1133800-1-senozhatsky@chromium.org> On (26/03/10 15:01), Sergey Senozhatsky wrote: > First, algorithm_params_store(), like any sysfs handler, > should grab device init lock. > > Second, like any write() sysfs handler, it should grab > device init lock in exclusive mode. > > Third, it should not permit change of algos' parameters > after device init, as this doesn't make sense - we cannot > compress with one C/D dict and then just change C/D dict > to a different one, for example. > > Fixes: 4eac932103a5d ("zram: introduce algorithm_params device attribute") > Cc: gao xu > Signed-off-by: Sergey Senozhatsky Andrew, I will include this patch into v2 of the zram fixups, can you please drop it for now? We need to protect algo lookup path as well, which accesses ->comp_algs. I'll fix that in v2.