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b=eGsUGSTpiafmq9qnZYc96i2HdB9tbJh72SG2LEaAEeiTSCxTh5JP7m1nmTfJhIzoN k2F4H8JjyFAU1a1yWcutcru1dWpCbuVBbvKFaZXBo43f/yTiwjQXN1XRt7Y5y7lDFZ yUDGShat0NmHZcVp4CRIZwzfqaOdOf1aAD+knhCJC4vqNfe5uEEMnE/lSxwjL2BNEU oq2nCa4fRP++Y4ZXmIrpzvgk2IMUH5HHW4PWT6X8xTPMJvkF+azOwPb/zZmT9Balvv K2AJfP7LvUtasObPCCPkUs3EvWssoVrw8MAQkuE6InWpZkJE9LVopRnE9pOYBIyvZr OGeMNa/sinTAQ== From: Pratyush Yadav To: Pasha Tatashin Cc: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, changyuanl@google.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 Subject: Re: [RFC v2 10/16] luo: luo_ioctl: add ioctl interface In-Reply-To: <20250515182322.117840-11-pasha.tatashin@soleen.com> References: <20250515182322.117840-1-pasha.tatashin@soleen.com> <20250515182322.117840-11-pasha.tatashin@soleen.com> Date: Thu, 05 Jun 2025 18:15:55 +0200 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Stat-Signature: cusw65bo1nqkcdegp7xa5zzjxzehr7si X-Rspamd-Queue-Id: 4367140012 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1749140165-775155 X-HE-Meta: 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 J/JeYq8c AOkGDgfvug2CK2HRsS2hwwKdDyVD46WhFDWsskOFNnQqfGas2pz8fqjuNW8zFG56K7uOfkCI/bXfYb278h0f3zUBypE0NImVcmUL5rqyzoOMHqFJ56D2+WNuIJ1wvl76vtIeVL3asVYGT5zUoFXBvMEMigTI3KoNTHf0rRzIE+OSM6A1EXxyIaSEgUWuHj2bgww0lLu+3FPN9+RGB245exjkCPmsm2C+G3Vw5RHkEfbJpQbM313oCVEtmxPEgs1Y2BKqTHENbm5Y5V7qsoSx9CNxQSAJs9kq1ZVLN/QLzcuKTl6UsZVdCBvUj1DSCEoPhAXvo1r0V0JTL6KrM5t2czJA5os5X1WoAO85Y X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, May 15 2025, Pasha Tatashin wrote: > Introduce the user-space interface for the Live Update Orchestrator > via ioctl commands, enabling external control over the live update > process and management of preserved resources. > > Create a misc character device at /dev/liveupdate. Access > to this device requires the CAP_SYS_ADMIN capability. > > A new UAPI header, , defines the necessary > structures. The magic number is registered in > Documentation/userspace-api/ioctl/ioctl-number.rst. > > Signed-off-by: Pasha Tatashin > --- [...] > +static int luo_ioctl_fd_preserve(struct liveupdate_fd *luo_fd) > +{ > + struct file *file; > + int ret; > + > + file = fget(luo_fd->fd); > + if (!file) { > + pr_err("Bad file descriptor\n"); > + return -EBADF; > + } > + > + ret = luo_register_file(&luo_fd->token, file); > + if (ret) > + fput(file); > + > + return ret; > +} > + > +static int luo_ioctl_fd_unpreserve(u64 token) > +{ This leaks the refcount on the file that preserve took. Perhaps luo_unregister_file() should return the file it unregistered, so this can do fput(file)? > + return luo_unregister_file(token); > +} > + > +static int luo_ioctl_fd_restore(struct liveupdate_fd *luo_fd) > +{ > + struct file *file; > + int ret; > + int fd; > + > + fd = get_unused_fd_flags(O_CLOEXEC); > + if (fd < 0) { > + pr_err("Failed to allocate new fd: %d\n", fd); > + return fd; > + } > + > + ret = luo_retrieve_file(luo_fd->token, &file); > + if (ret < 0) { > + put_unused_fd(fd); > + > + return ret; > + } > + > + fd_install(fd, file); > + luo_fd->fd = fd; > + > + return 0; > +} > + > +static int luo_open(struct inode *inodep, struct file *filep) > +{ > + if (!capable(CAP_SYS_ADMIN)) > + return -EACCES; > + > + if (filep->f_flags & O_EXCL) > + return -EINVAL; > + > + return 0; > +} > + > +static long luo_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) > +{ > + void __user *argp = (void __user *)arg; > + struct liveupdate_fd luo_fd; > + enum liveupdate_state state; > + int ret = 0; > + u64 token; > + > + if (_IOC_TYPE(cmd) != LIVEUPDATE_IOCTL_TYPE) > + return -ENOTTY; > + > + switch (cmd) { > + case LIVEUPDATE_IOCTL_GET_STATE: > + state = READ_ONCE(luo_state); > + if (copy_to_user(argp, &state, sizeof(luo_state))) > + ret = -EFAULT; > + break; > + > + case LIVEUPDATE_IOCTL_EVENT_PREPARE: > + ret = luo_prepare(); > + break; > + > + case LIVEUPDATE_IOCTL_EVENT_FREEZE: > + ret = luo_freeze(); > + break; > + > + case LIVEUPDATE_IOCTL_EVENT_FINISH: > + ret = luo_finish(); > + break; > + > + case LIVEUPDATE_IOCTL_EVENT_CANCEL: > + ret = luo_cancel(); > + break; > + > + case LIVEUPDATE_IOCTL_FD_PRESERVE: > + if (copy_from_user(&luo_fd, argp, sizeof(luo_fd))) { > + ret = -EFAULT; > + break; > + } > + > + ret = luo_ioctl_fd_preserve(&luo_fd); > + if (!ret && copy_to_user(argp, &luo_fd, sizeof(luo_fd))) > + ret = -EFAULT; luo_unregister_file() is needed here on error. > + break; > + > + case LIVEUPDATE_IOCTL_FD_UNPRESERVE: > + if (copy_from_user(&token, argp, sizeof(u64))) { > + ret = -EFAULT; > + break; > + } > + > + ret = luo_ioctl_fd_unpreserve(token); > + break; > + > + case LIVEUPDATE_IOCTL_FD_RESTORE: > + if (copy_from_user(&luo_fd, argp, sizeof(luo_fd))) { > + ret = -EFAULT; > + break; > + } > + > + ret = luo_ioctl_fd_restore(&luo_fd); > + if (!ret && copy_to_user(argp, &luo_fd, sizeof(luo_fd))) > + ret = -EFAULT; > + break; > + > + default: > + pr_warn("ioctl: unknown command nr: 0x%x\n", _IOC_NR(cmd)); > + ret = -ENOTTY; > + break; > + } > + > + return ret; > +} [...] -- Regards, Pratyush Yadav