diff options
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 100 |
1 files changed, 64 insertions, 36 deletions
diff --git a/mm/util.c b/mm/util.c index 9834c4ab7d8e..e6351a80f248 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> @@ -300,52 +301,79 @@ void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) } #endif -/* - * Like get_user_pages_fast() except its IRQ-safe in that it won't fall - * back to the regular GUP. - * Note a difference with get_user_pages_fast: this always returns the - * number of pages pinned, 0 if no pages were pinned. - * If the architecture does not support this function, simply return with no - * pages pinned. +/** + * __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 __weak __get_user_pages_fast(unsigned long start, - int nr_pages, int write, struct page **pages) +int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, + struct task_struct *task, bool bypass_rlim) { - return 0; + unsigned long locked_vm, limit; + int ret = 0; + + lockdep_assert_held_write(&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(__get_user_pages_fast); +EXPORT_SYMBOL_GPL(__account_locked_vm); /** - * get_user_pages_fast() - pin user pages in memory - * @start: starting user address - * @nr_pages: number of pages from start to pin - * @gup_flags: flags modifying pin behaviour - * @pages: array that receives pointers to the pages pinned. - * Should be at least nr_pages long. - * - * get_user_pages_fast provides equivalent functionality to get_user_pages, - * operating on current and current->mm, with force=0 and vma=NULL. However - * unlike get_user_pages, it must be called without mmap_sem held. + * 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 * - * get_user_pages_fast may take mmap_sem and page table locks, so no - * assumptions can be made about lack of locking. get_user_pages_fast is to be - * implemented in a way that is advantageous (vs get_user_pages()) when the - * user memory area is already faulted in and present in ptes. However if the - * pages have to be faulted in, it may turn out to be slightly slower so - * callers need to carefully consider what to use. On many architectures, - * get_user_pages_fast simply falls back to get_user_pages. + * Assumes a non-NULL @mm is valid (i.e. at least one reference on it). * - * Return: number of pages pinned. This may be fewer than the number - * requested. If nr_pages is 0 or negative, returns 0. If no pages - * were pinned, returns -errno. + * Return: + * * 0 on success, or if mm is NULL + * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. */ -int __weak get_user_pages_fast(unsigned long start, - int nr_pages, unsigned int gup_flags, - struct page **pages) +int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc) { - return get_user_pages_unlocked(start, nr_pages, pages, gup_flags); + 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(get_user_pages_fast); +EXPORT_SYMBOL_GPL(account_locked_vm); unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, |