diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/internal.h | 5 | ||||
| -rw-r--r-- | mm/memory-failure.c | 32 | ||||
| -rw-r--r-- | mm/memory.c | 63 |
3 files changed, 60 insertions, 40 deletions
diff --git a/mm/internal.h b/mm/internal.h index 69488205723..3438dd43a06 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -245,11 +245,6 @@ static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn, } #endif /* CONFIG_SPARSEMEM */ -int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, int len, unsigned int foll_flags, - struct page **pages, struct vm_area_struct **vmas, - int *nonblocking); - #define ZONE_RECLAIM_NOSCAN -2 #define ZONE_RECLAIM_FULL -1 #define ZONE_RECLAIM_SOME 0 diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 0207c2f6f8b..99ccb447262 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1487,35 +1487,3 @@ done: /* keep elevated page count for bad page */ return ret; } - -/* - * The caller must hold current->mm->mmap_sem in read mode. - */ -int is_hwpoison_address(unsigned long addr) -{ - pgd_t *pgdp; - pud_t pud, *pudp; - pmd_t pmd, *pmdp; - pte_t pte, *ptep; - swp_entry_t entry; - - pgdp = pgd_offset(current->mm, addr); - if (!pgd_present(*pgdp)) - return 0; - pudp = pud_offset(pgdp, addr); - pud = *pudp; - if (!pud_present(pud) || pud_large(pud)) - return 0; - pmdp = pmd_offset(pudp, addr); - pmd = *pmdp; - if (!pmd_present(pmd) || pmd_large(pmd)) - return 0; - ptep = pte_offset_map(pmdp, addr); - pte = *ptep; - pte_unmap(ptep); - if (!is_swap_pte(pte)) - return 0; - entry = pte_to_swp_entry(pte); - return is_hwpoison_entry(entry); -} -EXPORT_SYMBOL_GPL(is_hwpoison_address); diff --git a/mm/memory.c b/mm/memory.c index 5823698c2b7..346ee7e041f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1410,6 +1410,55 @@ no_page_table: return page; } +/** + * __get_user_pages() - pin user pages in memory + * @tsk: task_struct of target task + * @mm: mm_struct of target mm + * @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. Or NULL, if caller + * only intends to ensure the pages are faulted in. + * @vmas: array of pointers to vmas corresponding to each page. + * Or NULL if the caller does not require them. + * @nonblocking: whether waiting for disk IO or mmap_sem contention + * + * Returns 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. Each page returned must be released + * with a put_page() call when it is finished with. vmas will only + * remain valid while mmap_sem is held. + * + * Must be called with mmap_sem held for read or write. + * + * __get_user_pages walks a process's page tables and takes a reference to + * each struct page that each user address corresponds to at a given + * instant. That is, it takes the page that would be accessed if a user + * thread accesses the given user virtual address at that instant. + * + * This does not guarantee that the page exists in the user mappings when + * __get_user_pages returns, and there may even be a completely different + * page there in some cases (eg. if mmapped pagecache has been invalidated + * and subsequently re faulted). However it does guarantee that the page + * won't be freed completely. And mostly callers simply care that the page + * contains data that was valid *at some point in time*. Typically, an IO + * or similar operation cannot guarantee anything stronger anyway because + * locks can't be held over the syscall boundary. + * + * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If + * the page is written to, set_page_dirty (or set_page_dirty_lock, as + * appropriate) must be called after the page is finished with, and + * before put_page is called. + * + * If @nonblocking != NULL, __get_user_pages will not wait for disk IO + * or mmap_sem contention, and if waiting is needed to pin all pages, + * *@nonblocking will be set to 0. + * + * In most cases, get_user_pages or get_user_pages_fast should be used + * instead of __get_user_pages. __get_user_pages should be used only if + * you need some special @gup_flags. + */ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, int nr_pages, unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas, @@ -1527,9 +1576,16 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, if (ret & VM_FAULT_ERROR) { if (ret & VM_FAULT_OOM) return i ? i : -ENOMEM; - if (ret & - (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE| - VM_FAULT_SIGBUS)) + if (ret & (VM_FAULT_HWPOISON | + VM_FAULT_HWPOISON_LARGE)) { + if (i) + return i; + else if (gup_flags & FOLL_HWPOISON) + return -EHWPOISON; + else + return -EFAULT; + } + if (ret & VM_FAULT_SIGBUS) return i ? i : -EFAULT; BUG(); } @@ -1578,6 +1634,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } while (nr_pages); return i; } +EXPORT_SYMBOL(__get_user_pages); /** * get_user_pages() - pin user pages in memory |