diff --git a/drivers/char/mem.c b/drivers/char/mem.c index bbee97ff355..64551ab6be0 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -625,65 +625,10 @@ static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out, return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null); } -#ifdef CONFIG_MMU -/* - * For fun, we are using the MMU for this. - */ -static inline size_t read_zero_pagealigned(char __user * buf, size_t size) -{ - struct mm_struct *mm; - struct vm_area_struct * vma; - unsigned long addr=(unsigned long)buf; - - mm = current->mm; - /* Oops, this was forgotten before. -ben */ - down_read(&mm->mmap_sem); - - /* For private mappings, just map in zero pages. */ - for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) { - unsigned long count; - - if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0) - goto out_up; - if (vma->vm_flags & (VM_SHARED | VM_HUGETLB)) - break; - count = vma->vm_end - addr; - if (count > size) - count = size; - - zap_page_range(vma, addr, count, NULL); - if (zeromap_page_range(vma, addr, count, PAGE_COPY)) - break; - - size -= count; - buf += count; - addr += count; - if (size == 0) - goto out_up; - } - - up_read(&mm->mmap_sem); - - /* The shared case is hard. Let's do the conventional zeroing. */ - do { - unsigned long unwritten = clear_user(buf, PAGE_SIZE); - if (unwritten) - return size + unwritten - PAGE_SIZE; - cond_resched(); - buf += PAGE_SIZE; - size -= PAGE_SIZE; - } while (size); - - return size; -out_up: - up_read(&mm->mmap_sem); - return size; -} - static ssize_t read_zero(struct file * file, char __user * buf, size_t count, loff_t *ppos) { - unsigned long left, unwritten, written = 0; + size_t written; if (!count) return 0; @@ -691,69 +636,33 @@ static ssize_t read_zero(struct file * file, char __user * buf, if (!access_ok(VERIFY_WRITE, buf, count)) return -EFAULT; - left = count; + written = 0; + while (count) { + unsigned long unwritten; + size_t chunk = count; - /* do we want to be clever? Arbitrary cut-off */ - if (count >= PAGE_SIZE*4) { - unsigned long partial; - - /* How much left of the page? */ - partial = (PAGE_SIZE-1) & -(unsigned long) buf; - unwritten = clear_user(buf, partial); - written = partial - unwritten; + if (chunk > PAGE_SIZE) + chunk = PAGE_SIZE; /* Just for latency reasons */ + unwritten = clear_user(buf, chunk); + written += chunk - unwritten; if (unwritten) - goto out; - left -= partial; - buf += partial; - unwritten = read_zero_pagealigned(buf, left & PAGE_MASK); - written += (left & PAGE_MASK) - unwritten; - if (unwritten) - goto out; - buf += left & PAGE_MASK; - left &= ~PAGE_MASK; + break; + buf += chunk; + count -= chunk; + cond_resched(); } - unwritten = clear_user(buf, left); - written += left - unwritten; -out: return written ? written : -EFAULT; } static int mmap_zero(struct file * file, struct vm_area_struct * vma) { - int err; - +#ifndef CONFIG_MMU + return -ENOSYS; +#endif if (vma->vm_flags & VM_SHARED) return shmem_zero_setup(vma); - err = zeromap_page_range(vma, vma->vm_start, - vma->vm_end - vma->vm_start, vma->vm_page_prot); - BUG_ON(err == -EEXIST); - return err; + return 0; } -#else /* CONFIG_MMU */ -static ssize_t read_zero(struct file * file, char * buf, - size_t count, loff_t *ppos) -{ - size_t todo = count; - - while (todo) { - size_t chunk = todo; - - if (chunk > 4096) - chunk = 4096; /* Just for latency reasons */ - if (clear_user(buf, chunk)) - return -EFAULT; - buf += chunk; - todo -= chunk; - cond_resched(); - } - return count; -} - -static int mmap_zero(struct file * file, struct vm_area_struct * vma) -{ - return -ENOSYS; -} -#endif /* CONFIG_MMU */ static ssize_t write_full(struct file * file, const char __user * buf, size_t count, loff_t *ppos) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index b1013f34085..f3037c645ca 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1725,7 +1725,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file) &page, &vma) <= 0) { DUMP_SEEK(PAGE_SIZE); } else { - if (page == ZERO_PAGE(addr)) { + if (page == ZERO_PAGE(0)) { if (!dump_seek(file, PAGE_SIZE)) { page_cache_release(page); goto end_coredump; diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 2f5d8dbe676..c5ca2f0aca7 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1488,7 +1488,7 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size, &page, &vma) <= 0) { DUMP_SEEK(file->f_pos + PAGE_SIZE); } - else if (page == ZERO_PAGE(addr)) { + else if (page == ZERO_PAGE(0)) { page_cache_release(page); DUMP_SEEK(file->f_pos + PAGE_SIZE); } diff --git a/fs/direct-io.c b/fs/direct-io.c index b5928a7b6a5..acf0da1bd25 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -163,7 +163,7 @@ static int dio_refill_pages(struct dio *dio) up_read(¤t->mm->mmap_sem); if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) { - struct page *page = ZERO_PAGE(dio->curr_user_address); + struct page *page = ZERO_PAGE(0); /* * A memory fault, but the filesystem has some outstanding * mapped blocks. We need to use those blocks up to avoid @@ -763,7 +763,7 @@ static void dio_zero_block(struct dio *dio, int end) this_chunk_bytes = this_chunk_blocks << dio->blkbits; - page = ZERO_PAGE(dio->curr_user_address); + page = ZERO_PAGE(0); if (submit_page_section(dio, page, 0, this_chunk_bytes, dio->next_block_for_io)) return; diff --git a/include/linux/mm.h b/include/linux/mm.h index 291c4cc06ea..fbbc29a29df 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -779,8 +779,6 @@ void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *start_vma, unsigned long floor, unsigned long ceiling); int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma); -int zeromap_page_range(struct vm_area_struct *vma, unsigned long from, - unsigned long size, pgprot_t prot); void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows); diff --git a/mm/memory.c b/mm/memory.c index f82b359b274..2a8430844b6 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -966,7 +966,7 @@ no_page_table: * has touched so far, we don't want to allocate page tables. */ if (flags & FOLL_ANON) { - page = ZERO_PAGE(address); + page = ZERO_PAGE(0); if (flags & FOLL_GET) get_page(page); BUG_ON(flags & FOLL_WRITE); @@ -1111,95 +1111,6 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } EXPORT_SYMBOL(get_user_pages); -static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, - unsigned long addr, unsigned long end, pgprot_t prot) -{ - pte_t *pte; - spinlock_t *ptl; - int err = 0; - - pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); - if (!pte) - return -EAGAIN; - arch_enter_lazy_mmu_mode(); - do { - struct page *page = ZERO_PAGE(addr); - pte_t zero_pte = pte_wrprotect(mk_pte(page, prot)); - - if (unlikely(!pte_none(*pte))) { - err = -EEXIST; - pte++; - break; - } - page_cache_get(page); - page_add_file_rmap(page); - inc_mm_counter(mm, file_rss); - set_pte_at(mm, addr, pte, zero_pte); - } while (pte++, addr += PAGE_SIZE, addr != end); - arch_leave_lazy_mmu_mode(); - pte_unmap_unlock(pte - 1, ptl); - return err; -} - -static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, - unsigned long addr, unsigned long end, pgprot_t prot) -{ - pmd_t *pmd; - unsigned long next; - int err; - - pmd = pmd_alloc(mm, pud, addr); - if (!pmd) - return -EAGAIN; - do { - next = pmd_addr_end(addr, end); - err = zeromap_pte_range(mm, pmd, addr, next, prot); - if (err) - break; - } while (pmd++, addr = next, addr != end); - return err; -} - -static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, - unsigned long addr, unsigned long end, pgprot_t prot) -{ - pud_t *pud; - unsigned long next; - int err; - - pud = pud_alloc(mm, pgd, addr); - if (!pud) - return -EAGAIN; - do { - next = pud_addr_end(addr, end); - err = zeromap_pmd_range(mm, pud, addr, next, prot); - if (err) - break; - } while (pud++, addr = next, addr != end); - return err; -} - -int zeromap_page_range(struct vm_area_struct *vma, - unsigned long addr, unsigned long size, pgprot_t prot) -{ - pgd_t *pgd; - unsigned long next; - unsigned long end = addr + size; - struct mm_struct *mm = vma->vm_mm; - int err; - - BUG_ON(addr >= end); - pgd = pgd_offset(mm, addr); - flush_cache_range(vma, addr, end); - do { - next = pgd_addr_end(addr, end); - err = zeromap_pud_range(mm, pgd, addr, next, prot); - if (err) - break; - } while (pgd++, addr = next, addr != end); - return err; -} - pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl) { pgd_t * pgd = pgd_offset(mm, addr); @@ -1717,16 +1628,11 @@ gotten: if (unlikely(anon_vma_prepare(vma))) goto oom; - if (old_page == ZERO_PAGE(address)) { - new_page = alloc_zeroed_user_highpage_movable(vma, address); - if (!new_page) - goto oom; - } else { - new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); - if (!new_page) - goto oom; - cow_user_page(new_page, old_page, address, vma); - } + VM_BUG_ON(old_page == ZERO_PAGE(0)); + new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); + if (!new_page) + goto oom; + cow_user_page(new_page, old_page, address, vma); /* * Re-check the pte - we dropped the lock @@ -2252,39 +2158,24 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, spinlock_t *ptl; pte_t entry; - if (write_access) { - /* Allocate our own private page. */ - pte_unmap(page_table); + /* Allocate our own private page. */ + pte_unmap(page_table); - if (unlikely(anon_vma_prepare(vma))) - goto oom; - page = alloc_zeroed_user_highpage_movable(vma, address); - if (!page) - goto oom; + if (unlikely(anon_vma_prepare(vma))) + goto oom; + page = alloc_zeroed_user_highpage_movable(vma, address); + if (!page) + goto oom; - entry = mk_pte(page, vma->vm_page_prot); - entry = maybe_mkwrite(pte_mkdirty(entry), vma); - - page_table = pte_offset_map_lock(mm, pmd, address, &ptl); - if (!pte_none(*page_table)) - goto release; - inc_mm_counter(mm, anon_rss); - lru_cache_add_active(page); - page_add_new_anon_rmap(page, vma, address); - } else { - /* Map the ZERO_PAGE - vm_page_prot is readonly */ - page = ZERO_PAGE(address); - page_cache_get(page); - entry = mk_pte(page, vma->vm_page_prot); - - ptl = pte_lockptr(mm, pmd); - spin_lock(ptl); - if (!pte_none(*page_table)) - goto release; - inc_mm_counter(mm, file_rss); - page_add_file_rmap(page); - } + entry = mk_pte(page, vma->vm_page_prot); + entry = maybe_mkwrite(pte_mkdirty(entry), vma); + page_table = pte_offset_map_lock(mm, pmd, address, &ptl); + if (!pte_none(*page_table)) + goto release; + inc_mm_counter(mm, anon_rss); + lru_cache_add_active(page); + page_add_new_anon_rmap(page, vma, address); set_pte_at(mm, address, page_table, entry); /* No need to invalidate - it was non-present before */