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Tue, 17 Mar 2026 09:39:17 -0700 (PDT) MIME-Version: 1.0 References: <20260317025049.494931-1-pasha.tatashin@soleen.com> <20260317025049.494931-4-pasha.tatashin@soleen.com> In-Reply-To: <20260317025049.494931-4-pasha.tatashin@soleen.com> From: David Matlack Date: Tue, 17 Mar 2026 09:38:50 -0700 X-Gm-Features: AaiRm51I6Y9jp9_Iramv-jPdxRAPpMtjBUm1hRG8sOIFy-KOi6SP_ShQcC0KoCY Message-ID: Subject: Re: [PATCH 3/6] liveupdate: Defer file handler module refcounting to active sessions To: Pasha Tatashin Cc: rppt@kernel.org, pratyush@kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 1CD584000B X-Stat-Signature: tuy34t6qgq3xgw49jgexymoh7hf9bfbd X-Rspam-User: X-HE-Tag: 1773765559-169107 X-HE-Meta: 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 EBMYv5AP 7Odq3okZz/BKLKfOQL58UXQ0LPK5m+CRFKR9iPuc1BT1Ax7rH17HAHfnFJHxT4DY+WRaUS5Hp2Cd2IaQVVtYCUVLVB14LgvIZqs/C2aESnH8iBbdm8uC2HMALARlVnUtZ6/z2OePkQHnIS0K816T70NAAB/NLebSmli8v5NUHoV8eGCr9p7B8UmIcrXPKqdT6AzFmgpPld09MmyCq9h9V7m3Un42fZWuTC2e79nNVVuzye9SMTMoenpegdro7wcc0kg8jwE2gPEd0zCPUGh9JbopdQwY4NX08dLPT3oZP45GaiQw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 16, 2026 at 7:50=E2=80=AFPM Pasha Tatashin wrote: > @@ -281,7 +282,10 @@ int luo_preserve_file(struct luo_file_set *file_set,= u64 token, int fd) > scoped_guard(rwsem_read, &luo_file_handler_lock) { > list_private_for_each_entry(fh, &luo_file_handler_list, l= ist) { > if (fh->ops->can_preserve(fh, file)) { > - err =3D 0; > + if (try_module_get(fh->ops->owner)) > + err =3D 0; > + else > + err =3D -ENODEV; > break; > } > } Does LUO even need to take a reference to the file handler owner? LUO already takes a reference to the file, and the file should already be holding a reference to the file's owner, which should (must?) be the same as the file handler's owner. For FLB it makes more sense since the FLB's owner is likely not the same as the file's owner.