diff options
| -rw-r--r-- | include/linux/mm.h | 3 | ||||
| -rw-r--r-- | mm/filemap.c | 6 | ||||
| -rw-r--r-- | mm/memory.c | 5 |
3 files changed, 11 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 1f82adc85352..901435e3a9a9 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -151,6 +151,7 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_NONLINEAR 0x02 /* Fault was via a nonlinear mapping */ #define FAULT_FLAG_MKWRITE 0x04 /* Fault was mkwrite of existing pte */ #define FAULT_FLAG_ALLOW_RETRY 0x08 /* Retry fault if blocking */ +#define FAULT_FLAG_RETRY_NOWAIT 0x10 /* Don't drop mmap_sem and wait when retrying */ /* * This interface is used by x86 PAT code to identify a pfn mapping that is @@ -1545,6 +1546,8 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address, #define FOLL_GET 0x04 /* do get_page on page */ #define FOLL_DUMP 0x08 /* give error on hole if it would be zero */ #define FOLL_FORCE 0x10 /* get_user_pages read/write w/o permission */ +#define FOLL_NOWAIT 0x20 /* if a disk transfer is needed, start the IO + * and return without waiting upon it */ #define FOLL_MLOCK 0x40 /* mark page as mlocked */ #define FOLL_SPLIT 0x80 /* don't return transhuge pages, split them */ #define FOLL_HWPOISON 0x100 /* check page is hwpoisoned */ diff --git a/mm/filemap.c b/mm/filemap.c index 83a45d35468b..312b6eb78430 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -621,8 +621,10 @@ int __lock_page_or_retry(struct page *page, struct mm_struct *mm, __lock_page(page); return 1; } else { - up_read(&mm->mmap_sem); - wait_on_page_locked(page); + if (!(flags & FAULT_FLAG_RETRY_NOWAIT)) { + up_read(&mm->mmap_sem); + wait_on_page_locked(page); + } return 0; } } diff --git a/mm/memory.c b/mm/memory.c index e48945ab362b..615be5127ce1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1569,6 +1569,8 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, fault_flags |= FAULT_FLAG_WRITE; if (nonblocking) fault_flags |= FAULT_FLAG_ALLOW_RETRY; + if (foll_flags & FOLL_NOWAIT) + fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT); ret = handle_mm_fault(mm, vma, start, fault_flags); @@ -1595,7 +1597,8 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, tsk->min_flt++; if (ret & VM_FAULT_RETRY) { - *nonblocking = 0; + if (nonblocking) + *nonblocking = 0; return i; } |