From 83c54070ee1a2d05c89793884bea1a03f2851ed4 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Thu, 19 Jul 2007 01:47:05 -0700 Subject: mm: fault feedback #2 This patch completes Linus's wish that the fault return codes be made into bit flags, which I agree makes everything nicer. This requires requires all handle_mm_fault callers to be modified (possibly the modifications should go further and do things like fault accounting in handle_mm_fault -- however that would be for another patch). [akpm@linux-foundation.org: fix alpha build] [akpm@linux-foundation.org: fix s390 build] [akpm@linux-foundation.org: fix sparc build] [akpm@linux-foundation.org: fix sparc64 build] [akpm@linux-foundation.org: fix ia64 build] Signed-off-by: Nick Piggin Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Russell King Cc: Ian Molton Cc: Bryan Wu Cc: Mikael Starvik Cc: David Howells Cc: Yoshinori Sato Cc: "Luck, Tony" Cc: Hirokazu Takata Cc: Geert Uytterhoeven Cc: Roman Zippel Cc: Greg Ungerer Cc: Matthew Wilcox Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Paul Mundt Cc: Kazumoto Kojima Cc: Richard Curnow Cc: William Lee Irwin III Cc: "David S. Miller" Cc: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Cc: Miles Bader Cc: Chris Zankel Acked-by: Kyle McMartin Acked-by: Haavard Skinnemoen Acked-by: Ralf Baechle Acked-by: Andi Kleen Signed-off-by: Andrew Morton [ Still apparently needs some ARM and PPC loving - Linus ] Signed-off-by: Linus Torvalds --- mm/filemap.c | 6 ++--- mm/filemap_xip.c | 2 +- mm/hugetlb.c | 10 +++---- mm/memory.c | 80 ++++++++++++++++++++++++++++---------------------------- mm/shmem.c | 8 +++--- 5 files changed, 52 insertions(+), 54 deletions(-) (limited to 'mm') diff --git a/mm/filemap.c b/mm/filemap.c index 0876cc5..4fd9e3f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1322,9 +1322,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) struct page *page; unsigned long size; int did_readaround = 0; - int ret; - - ret = VM_FAULT_MINOR; + int ret = 0; size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; if (vmf->pgoff >= size) @@ -1408,7 +1406,7 @@ retry_find: */ mark_page_accessed(page); vmf->page = page; - return ret | FAULT_RET_LOCKED; + return ret | VM_FAULT_LOCKED; outside_data_content: /* diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index 847d5d7..53ee6a2 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -252,7 +252,7 @@ static int xip_file_fault(struct vm_area_struct *area, struct vm_fault *vmf) out: page_cache_get(page); vmf->page = page; - return VM_FAULT_MINOR; + return 0; } static struct vm_operations_struct xip_file_vm_ops = { diff --git a/mm/hugetlb.c b/mm/hugetlb.c index aaa7c1a..c4a573b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -469,7 +469,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, avoidcopy = (page_count(old_page) == 1); if (avoidcopy) { set_huge_ptep_writable(vma, address, ptep); - return VM_FAULT_MINOR; + return 0; } page_cache_get(old_page); @@ -494,7 +494,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, } page_cache_release(new_page); page_cache_release(old_page); - return VM_FAULT_MINOR; + return 0; } static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, @@ -551,7 +551,7 @@ retry: if (idx >= size) goto backout; - ret = VM_FAULT_MINOR; + ret = 0; if (!pte_none(*ptep)) goto backout; @@ -602,7 +602,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, return ret; } - ret = VM_FAULT_MINOR; + ret = 0; spin_lock(&mm->page_table_lock); /* Check for a racing update before calling hugetlb_cow */ @@ -641,7 +641,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, spin_unlock(&mm->page_table_lock); ret = hugetlb_fault(mm, vma, vaddr, 0); spin_lock(&mm->page_table_lock); - if (ret == VM_FAULT_MINOR) + if (!(ret & VM_FAULT_MAJOR)) continue; remainder = 0; diff --git a/mm/memory.c b/mm/memory.c index 23c8704..61d51da 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1068,31 +1068,30 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, cond_resched(); while (!(page = follow_page(vma, start, foll_flags))) { int ret; - ret = __handle_mm_fault(mm, vma, start, + ret = handle_mm_fault(mm, vma, start, foll_flags & FOLL_WRITE); + if (ret & VM_FAULT_ERROR) { + if (ret & VM_FAULT_OOM) + return i ? i : -ENOMEM; + else if (ret & VM_FAULT_SIGBUS) + return i ? i : -EFAULT; + BUG(); + } + if (ret & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->min_flt++; + /* - * The VM_FAULT_WRITE bit tells us that do_wp_page has - * broken COW when necessary, even if maybe_mkwrite - * decided not to set pte_write. We can thus safely do - * subsequent page lookups as if they were reads. + * The VM_FAULT_WRITE bit tells us that + * do_wp_page has broken COW when necessary, + * even if maybe_mkwrite decided not to set + * pte_write. We can thus safely do subsequent + * page lookups as if they were reads. */ if (ret & VM_FAULT_WRITE) foll_flags &= ~FOLL_WRITE; - - switch (ret & ~VM_FAULT_WRITE) { - case VM_FAULT_MINOR: - tsk->min_flt++; - break; - case VM_FAULT_MAJOR: - tsk->maj_flt++; - break; - case VM_FAULT_SIGBUS: - return i ? i : -EFAULT; - case VM_FAULT_OOM: - return i ? i : -ENOMEM; - default: - BUG(); - } + cond_resched(); } if (pages) { @@ -1639,7 +1638,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, { struct page *old_page, *new_page; pte_t entry; - int reuse = 0, ret = VM_FAULT_MINOR; + int reuse = 0, ret = 0; struct page *dirty_page = NULL; old_page = vm_normal_page(vma, address, orig_pte); @@ -1835,8 +1834,8 @@ static int unmap_mapping_range_vma(struct vm_area_struct *vma, /* * files that support invalidating or truncating portions of the * file from under mmaped areas must have their ->fault function - * return a locked page (and FAULT_RET_LOCKED code). This provides - * synchronisation against concurrent unmapping here. + * return a locked page (and set VM_FAULT_LOCKED in the return). + * This provides synchronisation against concurrent unmapping here. */ again: @@ -2140,7 +2139,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page *page; swp_entry_t entry; pte_t pte; - int ret = VM_FAULT_MINOR; + int ret = 0; if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) goto out; @@ -2208,8 +2207,9 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, unlock_page(page); if (write_access) { + /* XXX: We could OR the do_wp_page code with this one? */ if (do_wp_page(mm, vma, address, - page_table, pmd, ptl, pte) == VM_FAULT_OOM) + page_table, pmd, ptl, pte) & VM_FAULT_OOM) ret = VM_FAULT_OOM; goto out; } @@ -2280,7 +2280,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, lazy_mmu_prot_update(entry); unlock: pte_unmap_unlock(page_table, ptl); - return VM_FAULT_MINOR; + return 0; release: page_cache_release(page); goto unlock; @@ -2323,11 +2323,11 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (likely(vma->vm_ops->fault)) { ret = vma->vm_ops->fault(vma, &vmf); - if (unlikely(ret & (VM_FAULT_ERROR | FAULT_RET_NOPAGE))) - return (ret & VM_FAULT_MASK); + if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) + return ret; } else { /* Legacy ->nopage path */ - ret = VM_FAULT_MINOR; + ret = 0; vmf.page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); /* no page was available -- either SIGBUS or OOM */ if (unlikely(vmf.page == NOPAGE_SIGBUS)) @@ -2340,7 +2340,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, * For consistency in subsequent calls, make the faulted page always * locked. */ - if (unlikely(!(ret & FAULT_RET_LOCKED))) + if (unlikely(!(ret & VM_FAULT_LOCKED))) lock_page(vmf.page); else VM_BUG_ON(!PageLocked(vmf.page)); @@ -2356,7 +2356,8 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, ret = VM_FAULT_OOM; goto out; } - page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); + page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, + vma, address); if (!page) { ret = VM_FAULT_OOM; goto out; @@ -2384,7 +2385,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, * is better done later. */ if (!page->mapping) { - ret = VM_FAULT_MINOR; + ret = 0; anon = 1; /* no anon but release vmf.page */ goto out; } @@ -2447,7 +2448,7 @@ out_unlocked: put_page(dirty_page); } - return (ret & VM_FAULT_MASK); + return ret; } static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, @@ -2486,7 +2487,6 @@ static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, spinlock_t *ptl; pte_t entry; unsigned long pfn; - int ret = VM_FAULT_MINOR; pte_unmap(page_table); BUG_ON(!(vma->vm_flags & VM_PFNMAP)); @@ -2498,7 +2498,7 @@ static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, else if (unlikely(pfn == NOPFN_SIGBUS)) return VM_FAULT_SIGBUS; else if (unlikely(pfn == NOPFN_REFAULT)) - return VM_FAULT_MINOR; + return 0; page_table = pte_offset_map_lock(mm, pmd, address, &ptl); @@ -2510,7 +2510,7 @@ static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, set_pte_at(mm, address, page_table, entry); } pte_unmap_unlock(page_table, ptl); - return ret; + return 0; } /* @@ -2531,7 +2531,7 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, pgoff_t pgoff; if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) - return VM_FAULT_MINOR; + return 0; if (unlikely(!(vma->vm_flags & VM_NONLINEAR) || !(vma->vm_flags & VM_CAN_NONLINEAR))) { @@ -2615,13 +2615,13 @@ static inline int handle_pte_fault(struct mm_struct *mm, } unlock: pte_unmap_unlock(pte, ptl); - return VM_FAULT_MINOR; + return 0; } /* * By the time we get here, we already hold the mm semaphore */ -int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, +int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access) { pgd_t *pgd; @@ -2650,7 +2650,7 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, return handle_pte_fault(mm, vma, address, pte, pmd, write_access); } -EXPORT_SYMBOL_GPL(__handle_mm_fault); +EXPORT_SYMBOL_GPL(handle_mm_fault); #ifndef __PAGETABLE_PUD_FOLDED /* diff --git a/mm/shmem.c b/mm/shmem.c index 0a555af..ad155c7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1103,7 +1103,7 @@ static int shmem_getpage(struct inode *inode, unsigned long idx, return -EFBIG; if (type) - *type = VM_FAULT_MINOR; + *type = 0; /* * Normally, filepage is NULL on entry, and either found @@ -1138,9 +1138,9 @@ repeat: if (!swappage) { shmem_swp_unmap(entry); /* here we actually do the io */ - if (type && *type == VM_FAULT_MINOR) { + if (type && !(*type & VM_FAULT_MAJOR)) { __count_vm_event(PGMAJFAULT); - *type = VM_FAULT_MAJOR; + *type |= VM_FAULT_MAJOR; } spin_unlock(&info->lock); swappage = shmem_swapin(info, swap, idx); @@ -1323,7 +1323,7 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); mark_page_accessed(vmf->page); - return ret | FAULT_RET_LOCKED; + return ret | VM_FAULT_LOCKED; } #ifdef CONFIG_NUMA -- cgit v1.1