[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 --- fs/exec.c | 3 + fs/proc/base.c | 73 +++++++++++++++++++++++++++++++++++++++++ include/linux/sched.h | 3 + include/linux/sysids.h | 24 +++++++++++++ kernel/Makefile | 2 - kernel/exit.c | 4 ++ kernel/fork.c | 2 + kernel/nextid.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++ 8 files changed, 196 insertions(+), 1 deletion(-) Index: linux-2.6.25-rc8-mm1/include/linux/sysids.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.25-rc8-mm1/include/linux/sysids.h 2008-04-04 13:53:04.000000000 +0200 @@ -0,0 +1,24 @@ +/* + * 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 *, size_t); +extern int set_nextid(struct task_struct *, char *); +extern int reset_nextid(struct task_struct *); + +static inline void exit_nextid(struct task_struct *tsk) +{ + reset_nextid(tsk); +} + +#endif /* _LINUX_SYSIDS_H */ Index: linux-2.6.25-rc8-mm1/include/linux/sched.h =================================================================== --- linux-2.6.25-rc8-mm1.orig/include/linux/sched.h 2008-04-04 13:11:37.000000000 +0200 +++ linux-2.6.25-rc8-mm1/include/linux/sched.h 2008-04-04 13:55:10.000000000 +0200 @@ -88,6 +88,7 @@ struct sched_param { #include #include #include +#include #include @@ -1278,6 +1279,8 @@ 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-rc8-mm1/fs/proc/base.c =================================================================== --- linux-2.6.25-rc8-mm1.orig/fs/proc/base.c 2008-04-04 13:11:35.000000000 +0200 +++ linux-2.6.25-rc8-mm1/fs/proc/base.c 2008-04-04 13:57:18.000000000 +0200 @@ -1138,6 +1138,77 @@ 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 >= PAGE_SIZE) + count = PAGE_SIZE - 1; + + length = -ENOMEM; + page = (char *) __get_free_page(GFP_TEMPORARY); + if (!page) + goto out; + + length = get_nextid(task, (char *) page, count); + 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: @@ -2453,6 +2524,7 @@ 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, @@ -2779,6 +2851,7 @@ 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-rc8-mm1/kernel/Makefile =================================================================== --- linux-2.6.25-rc8-mm1.orig/kernel/Makefile 2008-04-04 13:11:37.000000000 +0200 +++ linux-2.6.25-rc8-mm1/kernel/Makefile 2008-04-04 13:58:22.000000000 +0200 @@ -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-rc8-mm1/kernel/nextid.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.25-rc8-mm1/kernel/nextid.c 2008-04-04 13:59:59.000000000 +0200 @@ -0,0 +1,86 @@ +/* + * 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 +#include + + + +ssize_t get_nextid(struct task_struct *task, char *buffer, size_t size) +{ + struct sys_id *sid; + + sid = task->next_id; + if (!sid) + return snprintf(buffer, size, "UNSET\n"); + + return snprintf(buffer, size, "LONG %ld\n", sid->id); +} + +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; +} + +int reset_nextid(struct task_struct *task) +{ + struct sys_id *sid; + + sid = task->next_id; + if (!sid) + return 0; + + task->next_id = NULL; + kfree(sid); + return 0; +} + +#define LONG_STR "LONG" +#define RESET_STR "RESET" + +/* + * 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; + + if (!out) + return -EINVAL; + + token = strsep(&out, " "); + + if (!strcmp(token, LONG_STR)) + return set_single_id(task, out); + else if (!strncmp(token, RESET_STR, strlen(RESET_STR))) + return reset_nextid(task); + else + return -EINVAL; +} Index: linux-2.6.25-rc8-mm1/kernel/fork.c =================================================================== --- linux-2.6.25-rc8-mm1.orig/kernel/fork.c 2008-04-04 13:11:37.000000000 +0200 +++ linux-2.6.25-rc8-mm1/kernel/fork.c 2008-04-04 14:00:35.000000000 +0200 @@ -1167,6 +1167,8 @@ 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); Index: linux-2.6.25-rc8-mm1/kernel/exit.c =================================================================== --- linux-2.6.25-rc8-mm1.orig/kernel/exit.c 2008-04-04 13:11:37.000000000 +0200 +++ linux-2.6.25-rc8-mm1/kernel/exit.c 2008-04-04 14:01:22.000000000 +0200 @@ -987,6 +987,10 @@ NORET_TYPE void do_exit(long code) proc_exit_connector(tsk); exit_notify(tsk, group_dead); + + if (unlikely(tsk->next_id)) + exit_nextid(tsk); + #ifdef CONFIG_NUMA mpol_free(tsk->mempolicy); tsk->mempolicy = NULL; Index: linux-2.6.25-rc8-mm1/fs/exec.c =================================================================== --- linux-2.6.25-rc8-mm1.orig/fs/exec.c 2008-04-04 13:11:34.000000000 +0200 +++ linux-2.6.25-rc8-mm1/fs/exec.c 2008-04-04 14:02:09.000000000 +0200 @@ -1024,6 +1024,9 @@ int flush_old_exec(struct linux_binprm * flush_signal_handlers(current, 0); flush_old_files(current->files); + if (unlikely(current->next_id)) + reset_nextid(current); + return 0; mmap_failed: -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/