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Fri, 08 Aug 2025 13:23:13 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20250807014442.3829950-1-pasha.tatashin@soleen.com> <20250807014442.3829950-30-pasha.tatashin@soleen.com> In-Reply-To: <20250807014442.3829950-30-pasha.tatashin@soleen.com> From: Pasha Tatashin Date: Fri, 8 Aug 2025 20:22:36 +0000 X-Gm-Features: Ac12FXwZELMUp6FmK0bakKcUqFiUYIIUNXgn4oPjuRKBZW9iuH-cHyWFuj5z7U0 Message-ID: Subject: Re: [PATCH v3 29/30] luo: allow preserving memfd To: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, changyuanl@google.com, pasha.tatashin@soleen.com, rppt@kernel.org, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, zhangguopeng@kylinos.cn, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, jrhilke@google.com Content-Type: text/plain; charset="UTF-8" > +static int memfd_luo_preserve_folios(struct memfd_luo_preserved_folio *pfolios, > + struct folio **folios, > + unsigned int nr_folios) > +{ > + unsigned int i; Should be 'long i' Otherwise in err_unpreserve we get into an infinite loop. Thank you Josh Hilke for noticing this. Pasha > + int err; > + > + for (i = 0; i < nr_folios; i++) { > + struct memfd_luo_preserved_folio *pfolio = &pfolios[i]; > + struct folio *folio = folios[i]; > + unsigned int flags = 0; > + unsigned long pfn; > + > + err = kho_preserve_folio(folio); > + if (err) > + goto err_unpreserve; > + > + pfn = folio_pfn(folio); > + if (folio_test_dirty(folio)) > + flags |= PRESERVED_FLAG_DIRTY; > + if (folio_test_uptodate(folio)) > + flags |= PRESERVED_FLAG_UPTODATE; > + > + pfolio->foliodesc = PRESERVED_FOLIO_MKDESC(pfn, flags); > + pfolio->index = folio->index; > + } > + > + return 0; > + > +err_unpreserve: > + i--; > + for (; i >= 0; i--) > + WARN_ON_ONCE(kho_unpreserve_folio(folios[i])); > + return err; > +} > +