On Fri, 28 Mar 2008, [EMAIL PROTECTED] wrote:
> [PATCH 01/04] > > This patch proposes the procfs facilities needed to feed the id for the > next object to be allocated. > > if an > echo "LONG XX" > /proc/self/next_id > is issued, next object to be created will have XX as its id. > > This applies to objects that need a single id, such as ipc objects. > > Signed-off-by: Nadia Derbey <[EMAIL PROTECTED]> > > --- > fs/proc/base.c | 73 > +++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/sched.h | 3 ++ > include/linux/sysids.h | 18 ++++++++++++ > kernel/Makefile | 2 - > kernel/fork.c | 2 + > kernel/nextid.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++ > 6 files changed, 166 insertions(+), 1 deletion(-) > > Index: linux-2.6.25-rc3-mm1/include/linux/sysids.h > =================================================================== > --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ linux-2.6.25-rc3-mm1/include/linux/sysids.h 2008-03-27 > 18:02:08.000000000 +0100 > @@ -0,0 +1,18 @@ > +/* > + * include/linux/sysids.h > + * > + * Definitions to support object creation with predefined id. > + * > + */ > + > +#ifndef _LINUX_SYSIDS_H > +#define _LINUX_SYSIDS_H > + > +struct sys_id { > + long id; > +}; > + > +extern ssize_t get_nextid(struct task_struct *, char *); > +extern int set_nextid(struct task_struct *, char *); > + > +#endif /* _LINUX_SYSIDS_H */ > Index: linux-2.6.25-rc3-mm1/include/linux/sched.h > =================================================================== > --- linux-2.6.25-rc3-mm1.orig/include/linux/sched.h 2008-03-10 > 09:18:46.000000000 +0100 > +++ linux-2.6.25-rc3-mm1/include/linux/sched.h 2008-03-10 > 09:28:30.000000000 +0100 > @@ -87,6 +87,7 @@ struct sched_param { > #include <linux/task_io_accounting.h> > #include <linux/kobject.h> > #include <linux/latencytop.h> > +#include <linux/sysids.h> > > #include <asm/processor.h> > > @@ -1261,6 +1262,8 @@ struct task_struct { > int latency_record_count; > struct latency_record latency_record[LT_SAVECOUNT]; > #endif > + /* Id to assign to the next resource to be created */ > + struct sys_id *next_id; > }; > > /* > Index: linux-2.6.25-rc3-mm1/fs/proc/base.c > =================================================================== > --- linux-2.6.25-rc3-mm1.orig/fs/proc/base.c 2008-03-10 09:19:39.000000000 > +0100 > +++ linux-2.6.25-rc3-mm1/fs/proc/base.c 2008-03-21 12:03:09.000000000 > +0100 > @@ -1080,6 +1080,77 @@ static const struct file_operations proc > #endif > > > +static ssize_t next_id_read(struct file *file, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct task_struct *task; > + char *page; > + ssize_t length; > + > + task = get_proc_task(file->f_path.dentry->d_inode); > + if (!task) > + return -ESRCH; > + > + if (count > PROC_BLOCK_SIZE) > + count = PROC_BLOCK_SIZE; > + > + length = -ENOMEM; > + page = (char *) __get_free_page(GFP_TEMPORARY); > + if (!page) > + goto out; > + > + length = get_nextid(task, (char *) page); > + if (length >= 0) > + length = simple_read_from_buffer(buf, count, ppos, > + (char *)page, length); > + free_page((unsigned long) page); > + > +out: > + put_task_struct(task); > + return length; > +} > + > +static ssize_t next_id_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct inode *inode = file->f_path.dentry->d_inode; > + char *page; > + ssize_t length; > + > + if (pid_task(proc_pid(inode), PIDTYPE_PID) != current) > + return -EPERM; > + > + if (count >= PAGE_SIZE) > + count = PAGE_SIZE - 1; > + > + if (*ppos != 0) { > + /* No partial writes. */ > + return -EINVAL; > + } > + page = (char *)__get_free_page(GFP_TEMPORARY); > + if (!page) > + return -ENOMEM; > + length = -EFAULT; > + if (copy_from_user(page, buf, count)) > + goto out_free_page; > + > + page[count] = '\0'; > + > + length = set_nextid(current, page); > + if (!length) > + length = count; > + > +out_free_page: > + free_page((unsigned long) page); > + return length; > +} > + > +static const struct file_operations proc_next_id_operations = { > + .read = next_id_read, > + .write = next_id_write, > +}; > + > + > #ifdef CONFIG_SCHED_DEBUG > /* > * Print out various scheduling related per-task fields: > @@ -2391,6 +2462,7 @@ static const struct pid_entry tgid_base_ > #ifdef CONFIG_TASK_IO_ACCOUNTING > INF("io", S_IRUGO, pid_io_accounting), > #endif > + REG("next_id", S_IRUGO|S_IWUSR, next_id), > }; > > static int proc_tgid_base_readdir(struct file * filp, > @@ -2716,6 +2788,7 @@ static const struct pid_entry tid_base_s > #ifdef CONFIG_FAULT_INJECTION > REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject), > #endif > + REG("next_id", S_IRUGO|S_IWUSR, next_id), > }; > > static int proc_tid_base_readdir(struct file * filp, > Index: linux-2.6.25-rc3-mm1/kernel/Makefile > =================================================================== > --- linux-2.6.25-rc3-mm1.orig/kernel/Makefile 2008-03-10 09:19:01.000000000 > +0100 > +++ linux-2.6.25-rc3-mm1/kernel/Makefile 2008-03-20 17:29:50.000000000 > +0100 > @@ -9,7 +9,7 @@ obj-y = sched.o fork.o exec_domain.o > rcupdate.o extable.o params.o posix-timers.o \ > kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \ > hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \ > - notifier.o ksysfs.o pm_qos_params.o > + notifier.o ksysfs.o pm_qos_params.o nextid.o > > obj-$(CONFIG_SYSCTL_SYSCALL_CHECK) += sysctl_check.o > obj-$(CONFIG_STACKTRACE) += stacktrace.o > Index: linux-2.6.25-rc3-mm1/kernel/nextid.c > =================================================================== > --- /dev/null 1970-01-01 00:00:00.000000000 +0000 > +++ linux-2.6.25-rc3-mm1/kernel/nextid.c 2008-03-27 18:02:08.000000000 > +0100 > @@ -0,0 +1,69 @@ > +/* > + * linux/kernel/nextid.c > + * > + * > + * Provide the get_nextid() / set_nextid() routines > + * (called from fs/proc/base.c). > + * They allow to specify the id for the next resource to be allocated, > + * instead of letting the allocator set it for us. > + */ > + > +#include <linux/sched.h> > +#include <linux/ctype.h> > + > + > + > +ssize_t get_nextid(struct task_struct *task, char *buffer) > +{ > + struct sys_id *sid; > + > + sid = task->next_id; > + if (!sid) > + return snprintf(buffer, sizeof(buffer), "-1\n"); > + > + return snprintf(buffer, sizeof(buffer), "%ld\n", sid->id); > +} Since the input format is "LONG <id>", why not have the output format be the same ? This way, if in the future there are other formats (eg CHAR, IPv4 ...). Same comment for the next patch, for LONG<n> format. (disclaimer: at this point I don't see why one would want to read this file, or usage for other formats...) > + > +static int set_single_id(struct task_struct *task, char *buffer) > +{ > + struct sys_id *sid; > + long next_id; > + char *end; > + > + next_id = simple_strtol(buffer, &end, 0); > + if (end == buffer || (end && !isspace(*end))) > + return -EINVAL; > + > + sid = task->next_id; > + if (!sid) { > + sid = kzalloc(sizeof(*sid), GFP_KERNEL); > + if (!sid) > + return -ENOMEM; > + task->next_id = sid; > + } > + > + sid->id = next_id; > + > + return 0; > +} > + > +#define SINGLE_LONG "LONG" > + > +/* > + * Parses a line written to /proc/self/next_id. > + * this line has the following format: > + * LONG id --> a single id is specified > + */ > +int set_nextid(struct task_struct *task, char *buffer) > +{ > + char *token, *out = buffer; > + > + token = strsep(&out, " "); > + if (!token || !out) > + return -EINVAL; > + > + if (!strcmp(token, SINGLE_LONG)) > + return set_single_id(task, out); > + else > + return -EINVAL; > +} > Index: linux-2.6.25-rc3-mm1/kernel/fork.c > =================================================================== > --- linux-2.6.25-rc3-mm1.orig/kernel/fork.c 2008-03-27 18:01:56.000000000 > +0100 > +++ linux-2.6.25-rc3-mm1/kernel/fork.c 2008-03-27 18:02:42.000000000 > +0100 > @@ -1166,6 +1166,8 @@ static struct task_struct *copy_process( > p->blocked_on = NULL; /* not blocked yet */ > #endif > > + p->next_id = NULL; > + > /* Perform scheduler related setup. Assign this task to a CPU. */ > sched_fork(p, clone_flags); Freeing this memory when the task terminates could be helpful, too. Probably execve() is another good candidate to free this, just in case. Oren. _______________________________________________ Containers mailing list [EMAIL PROTECTED] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list Devel@openvz.org https://openvz.org/mailman/listinfo/devel