Rather than modifying the 'address' field of the 'struct vm_fault' passed to do_set_pte(), leave that to identify the real faulting address and pass in the virtual address to be mapped by the new pte as a separate argument.
This makes FAULT_FLAG_PREFAULT redundant, as a prefault entry can be identified simply by comparing the new address parameter with the faulting address, so remove the redundant flag at the same time. Cc: Kirill A. Shutemov <kirill.shute...@linux.intel.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Will Deacon <w...@kernel.org> --- include/linux/mm.h | 7 ++----- mm/filemap.c | 21 +++++++-------------- mm/memory.c | 10 +++++----- 3 files changed, 14 insertions(+), 24 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index b4a5cb9bff7d..e0f056753bef 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -434,7 +434,6 @@ extern pgprot_t protection_map[16]; * @FAULT_FLAG_REMOTE: The fault is not for current task/mm. * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch. * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals. - * @FAULT_FLAG_PREFAULT: Fault was a prefault. * * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify * whether we would allow page faults to retry by specifying these two @@ -465,7 +464,6 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_REMOTE 0x80 #define FAULT_FLAG_INSTRUCTION 0x100 #define FAULT_FLAG_INTERRUPTIBLE 0x200 -#define FAULT_FLAG_PREFAULT 0x400 /* * The default fault flags that should be used by most of the @@ -503,8 +501,7 @@ static inline bool fault_flag_allow_retry_first(unsigned int flags) { FAULT_FLAG_USER, "USER" }, \ { FAULT_FLAG_REMOTE, "REMOTE" }, \ { FAULT_FLAG_INSTRUCTION, "INSTRUCTION" }, \ - { FAULT_FLAG_INTERRUPTIBLE, "INTERRUPTIBLE" }, \ - { FAULT_FLAG_PREFAULT, "PREFAULT" } + { FAULT_FLAG_INTERRUPTIBLE, "INTERRUPTIBLE" } /* * vm_fault is filled by the pagefault handler and passed to the vma's @@ -995,7 +992,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) } vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page); -void do_set_pte(struct vm_fault *vmf, struct page *page); +void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr); vm_fault_t finish_fault(struct vm_fault *vmf); vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf); diff --git a/mm/filemap.c b/mm/filemap.c index a6dc97906c8e..fb7a8d9b5603 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3018,8 +3018,7 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, struct file *file = vma->vm_file; struct address_space *mapping = file->f_mapping; pgoff_t last_pgoff = start_pgoff; - unsigned long address = vmf->address; - unsigned long flags = vmf->flags; + unsigned long addr; XA_STATE(xas, &mapping->i_pages, start_pgoff); struct page *head, *page; unsigned int mmap_miss = READ_ONCE(file->f_ra.mmap_miss); @@ -3035,8 +3034,8 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, goto out; } - vmf->address = vma->vm_start + ((start_pgoff - vma->vm_pgoff) << PAGE_SHIFT); - vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, &vmf->ptl); + addr = vma->vm_start + ((start_pgoff - vma->vm_pgoff) << PAGE_SHIFT); + vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl); do { page = find_subpage(head, xas.xa_index); if (PageHWPoison(page)) @@ -3045,7 +3044,7 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, if (mmap_miss > 0) mmap_miss--; - vmf->address += (xas.xa_index - last_pgoff) << PAGE_SHIFT; + addr += (xas.xa_index - last_pgoff) << PAGE_SHIFT; vmf->pte += xas.xa_index - last_pgoff; last_pgoff = xas.xa_index; @@ -3053,16 +3052,12 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, goto unlock; /* We're about to handle the fault */ - if (vmf->address == address) { - vmf->flags &= ~FAULT_FLAG_PREFAULT; + if (vmf->address == addr) ret = VM_FAULT_NOPAGE; - } else { - vmf->flags |= FAULT_FLAG_PREFAULT; - } - do_set_pte(vmf, page); + do_set_pte(vmf, page, addr); /* no need to invalidate: a not-present page won't be cached */ - update_mmu_cache(vma, vmf->address, vmf->pte); + update_mmu_cache(vma, addr, vmf->pte); unlock_page(head); continue; unlock: @@ -3072,8 +3067,6 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf, pte_unmap_unlock(vmf->pte, vmf->ptl); out: rcu_read_unlock(); - vmf->flags = flags; - vmf->address = address; WRITE_ONCE(file->f_ra.mmap_miss, mmap_miss); return ret; } diff --git a/mm/memory.c b/mm/memory.c index f0e7c589ca9d..7b1307873325 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3733,11 +3733,11 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) } #endif -void do_set_pte(struct vm_fault *vmf, struct page *page) +void do_set_pte(struct vm_fault *vmf, struct page *page, unsigned long addr) { struct vm_area_struct *vma = vmf->vma; bool write = vmf->flags & FAULT_FLAG_WRITE; - bool prefault = vmf->flags & FAULT_FLAG_PREFAULT; + bool prefault = vmf->address != addr; pte_t entry; flush_icache_page(vma, page); @@ -3753,13 +3753,13 @@ void do_set_pte(struct vm_fault *vmf, struct page *page) /* copy-on-write page */ if (write && !(vma->vm_flags & VM_SHARED)) { inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); - page_add_new_anon_rmap(page, vma, vmf->address, false); + page_add_new_anon_rmap(page, vma, addr, false); lru_cache_add_inactive_or_unevictable(page, vma); } else { inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); page_add_file_rmap(page, false); } - set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); + set_pte_at(vma->vm_mm, addr, vmf->pte, entry); } /** @@ -3819,7 +3819,7 @@ vm_fault_t finish_fault(struct vm_fault *vmf) ret = 0; /* Re-check under ptl */ if (likely(pte_none(*vmf->pte))) - do_set_pte(vmf, page); + do_set_pte(vmf, page, vmf->address); else ret = VM_FAULT_NOPAGE; -- 2.30.0.284.gd98b1dd5eaa7-goog