diff options
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c index 9834c4ab7d8e..021648a8a3a3 100644 --- a/mm/util.c +++ b/mm/util.c @@ -7,6 +7,7 @@ #include <linux/err.h> #include <linux/sched.h> #include <linux/sched/mm.h> +#include <linux/sched/signal.h> #include <linux/sched/task_stack.h> #include <linux/security.h> #include <linux/swap.h> @@ -347,6 +348,80 @@ int __weak get_user_pages_fast(unsigned long start, } EXPORT_SYMBOL_GPL(get_user_pages_fast); +/** + * __account_locked_vm - account locked pages to an mm's locked_vm + * @mm: mm to account against + * @pages: number of pages to account + * @inc: %true if @pages should be considered positive, %false if not + * @task: task used to check RLIMIT_MEMLOCK + * @bypass_rlim: %true if checking RLIMIT_MEMLOCK should be skipped + * + * Assumes @task and @mm are valid (i.e. at least one reference on each), and + * that mmap_sem is held as writer. + * + * Return: + * * 0 on success + * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. + */ +int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, + struct task_struct *task, bool bypass_rlim) +{ + unsigned long locked_vm, limit; + int ret = 0; + + lockdep_assert_held_exclusive(&mm->mmap_sem); + + locked_vm = mm->locked_vm; + if (inc) { + if (!bypass_rlim) { + limit = task_rlimit(task, RLIMIT_MEMLOCK) >> PAGE_SHIFT; + if (locked_vm + pages > limit) + ret = -ENOMEM; + } + if (!ret) + mm->locked_vm = locked_vm + pages; + } else { + WARN_ON_ONCE(pages > locked_vm); + mm->locked_vm = locked_vm - pages; + } + + pr_debug("%s: [%d] caller %ps %c%lu %lu/%lu%s\n", __func__, task->pid, + (void *)_RET_IP_, (inc) ? '+' : '-', pages << PAGE_SHIFT, + locked_vm << PAGE_SHIFT, task_rlimit(task, RLIMIT_MEMLOCK), + ret ? " - exceeded" : ""); + + return ret; +} +EXPORT_SYMBOL_GPL(__account_locked_vm); + +/** + * account_locked_vm - account locked pages to an mm's locked_vm + * @mm: mm to account against, may be NULL + * @pages: number of pages to account + * @inc: %true if @pages should be considered positive, %false if not + * + * Assumes a non-NULL @mm is valid (i.e. at least one reference on it). + * + * Return: + * * 0 on success, or if mm is NULL + * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. + */ +int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc) +{ + int ret; + + if (pages == 0 || !mm) + return 0; + + down_write(&mm->mmap_sem); + ret = __account_locked_vm(mm, pages, inc, current, + capable(CAP_IPC_LOCK)); + up_write(&mm->mmap_sem); + + return ret; +} +EXPORT_SYMBOL_GPL(account_locked_vm); + unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long pgoff) |