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Thu, 13 Apr 2023 17:12:05 -0700 (PDT) Date: Fri, 14 Apr 2023 00:11:53 +0000 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.40.0.634.g4ca3ef3211-goog Message-ID: <17bb8e925c08f27c627cd1f2bbb2714daf590c1d.1681430907.git.ackerleytng@google.com> Subject: [RFC PATCH 4/6] mm: mempolicy: Add and expose mpol_create From: Ackerley Tng To: kvm@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, qemu-devel@nongnu.org Cc: aarcange@redhat.com, ak@linux.intel.com, akpm@linux-foundation.org, arnd@arndb.de, bfields@fieldses.org, bp@alien8.de, chao.p.peng@linux.intel.com, corbet@lwn.net, dave.hansen@intel.com, david@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, hpa@zytor.com, hughd@google.com, jlayton@kernel.org, jmattson@google.com, joro@8bytes.org, jun.nakajima@intel.com, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, luto@kernel.org, mail@maciej.szmigiero.name, mhocko@suse.com, michael.roth@amd.com, mingo@redhat.com, naoya.horiguchi@nec.com, pbonzini@redhat.com, qperret@google.com, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, steven.price@arm.com, tabba@google.com, tglx@linutronix.de, vannapurve@google.com, vbabka@suse.cz, vkuznets@redhat.com, wanpengli@tencent.com, wei.w.wang@intel.com, x86@kernel.org, yu.c.zhang@linux.intel.com, muchun.song@linux.dev, feng.tang@intel.com, brgerst@gmail.com, rdunlap@infradead.org, masahiroy@kernel.org, mailhol.vincent@wanadoo.fr, Ackerley Tng Received-SPF: pass client-ip=2607:f8b0:4864:20::b4a; envelope-from=3VZo4ZAsKCpQy082F92MHB44CC492.0CAE2AI-12J29BCB4BI.CF4@flex--ackerleytng.bounces.google.com; helo=mail-yb1-xb4a.google.com X-Spam_score_int: -95 X-Spam_score: -9.6 X-Spam_bar: --------- X-Spam_report: (-9.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, USER_IN_DEF_DKIM_WL=-7.5 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org mpol_create builds a mempolicy based on mode, nmask and maxnode. mpol_create is exposed for use in memfd_restricted_bind() in a later patch. Signed-off-by: Ackerley Tng --- include/linux/mempolicy.h | 2 ++ mm/mempolicy.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 9a2a2dd95432..15facd9de087 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -125,6 +125,8 @@ struct shared_policy { }; int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst); +struct mempolicy *mpol_create( + unsigned long mode, const unsigned long __user *nmask, unsigned long maxnode) void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol); int __mpol_set_shared_policy(struct shared_policy *info, struct mempolicy *mpol, unsigned long pgoff_start, unsigned long npages); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index f3fa5494e4a8..f4fe241c17ff 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -3181,3 +3181,42 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) p += scnprintf(p, buffer + maxlen - p, ":%*pbl", nodemask_pr_args(&nodes)); } + +/** + * mpol_create - build mempolicy based on mode, nmask and maxnode + * @mode: policy mode, as in MPOL_MODE_FLAGS + * @nmask: node mask from userspace + * @maxnode: number of valid bits in nmask + * + * Will allocate a new struct mempolicy that has to be released with + * mpol_put. Will also take and release the write lock mmap_lock in current->mm. + */ +struct mempolicy *mpol_create( + unsigned long mode, const unsigned long __user *nmask, unsigned long maxnode) +{ + int err; + unsigned short mode_flags; + nodemask_t nodes; + int lmode = mode; + struct mempolicy *mpol; + + err = sanitize_mpol_flags(&lmode, &mode_flags); + if (err) + return ERR_PTR(err); + + err = get_nodes(&nodes, nmask, maxnode); + if (err) + return ERR_PTR(err); + + mpol = mpol_new(mode, mode_flags, &nodes); + if (IS_ERR(mpol)) + return mpol; + + err = mpol_init_from_nodemask(mpol, &nodes, true); + if (err) { + mpol_put(mpol); + return ERR_PTR(err); + } + + return mpol; +}