diff options
| -rw-r--r-- | mm/msync.c | 196 |
1 files changed, 33 insertions, 163 deletions
@@ -7,149 +7,33 @@ /* * The msync() system call. */ -#include <linux/slab.h> -#include <linux/pagemap.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/mman.h> -#include <linux/hugetlb.h> -#include <linux/writeback.h> #include <linux/file.h> #include <linux/syscalls.h> -#include <asm/pgtable.h> -#include <asm/tlbflush.h> - -static unsigned long msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, - unsigned long addr, unsigned long end) -{ - pte_t *pte; - spinlock_t *ptl; - int progress = 0; - unsigned long ret = 0; - -again: - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); - do { - struct page *page; - - if (progress >= 64) { - progress = 0; - if (need_resched() || need_lockbreak(ptl)) - break; - } - progress++; - if (!pte_present(*pte)) - continue; - if (!pte_maybe_dirty(*pte)) - continue; - page = vm_normal_page(vma, addr, *pte); - if (!page) - continue; - if (ptep_clear_flush_dirty(vma, addr, pte) || - page_test_and_clear_dirty(page)) - ret += set_page_dirty(page); - progress += 3; - } while (pte++, addr += PAGE_SIZE, addr != end); - pte_unmap_unlock(pte - 1, ptl); - cond_resched(); - if (addr != end) - goto again; - return ret; -} - -static inline unsigned long msync_pmd_range(struct vm_area_struct *vma, - pud_t *pud, unsigned long addr, unsigned long end) -{ - pmd_t *pmd; - unsigned long next; - unsigned long ret = 0; - - pmd = pmd_offset(pud, addr); - do { - next = pmd_addr_end(addr, end); - if (pmd_none_or_clear_bad(pmd)) - continue; - ret += msync_pte_range(vma, pmd, addr, next); - } while (pmd++, addr = next, addr != end); - return ret; -} - -static inline unsigned long msync_pud_range(struct vm_area_struct *vma, - pgd_t *pgd, unsigned long addr, unsigned long end) -{ - pud_t *pud; - unsigned long next; - unsigned long ret = 0; - - pud = pud_offset(pgd, addr); - do { - next = pud_addr_end(addr, end); - if (pud_none_or_clear_bad(pud)) - continue; - ret += msync_pmd_range(vma, pud, addr, next); - } while (pud++, addr = next, addr != end); - return ret; -} - -static unsigned long msync_page_range(struct vm_area_struct *vma, - unsigned long addr, unsigned long end) -{ - pgd_t *pgd; - unsigned long next; - unsigned long ret = 0; - - /* For hugepages we can't go walking the page table normally, - * but that's ok, hugetlbfs is memory based, so we don't need - * to do anything more on an msync(). - */ - if (vma->vm_flags & VM_HUGETLB) - return 0; - - BUG_ON(addr >= end); - pgd = pgd_offset(vma->vm_mm, addr); - flush_cache_range(vma, addr, end); - do { - next = pgd_addr_end(addr, end); - if (pgd_none_or_clear_bad(pgd)) - continue; - ret += msync_pud_range(vma, pgd, addr, next); - } while (pgd++, addr = next, addr != end); - return ret; -} - /* * MS_SYNC syncs the entire file - including mappings. * - * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just - * marks the relevant pages dirty. The application may now run fsync() to + * MS_ASYNC does not start I/O (it used to, up to 2.5.67). + * Nor does it marks the relevant pages dirty (it used to up to 2.6.17). + * Now it doesn't do anything, since dirty pages are properly tracked. + * + * The application may now run fsync() to * write out the dirty pages and wait on the writeout and check the result. * Or the application may run fadvise(FADV_DONTNEED) against the fd to start * async writeout immediately. * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to * applications. */ -static int msync_interval(struct vm_area_struct *vma, unsigned long addr, - unsigned long end, int flags, - unsigned long *nr_pages_dirtied) -{ - struct file *file = vma->vm_file; - - if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) - return -EBUSY; - - if (file && (vma->vm_flags & VM_SHARED)) - *nr_pages_dirtied = msync_page_range(vma, addr, end); - return 0; -} - asmlinkage long sys_msync(unsigned long start, size_t len, int flags) { unsigned long end; + struct mm_struct *mm = current->mm; struct vm_area_struct *vma; int unmapped_error = 0; int error = -EINVAL; - int done = 0; if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) goto out; @@ -169,64 +53,50 @@ asmlinkage long sys_msync(unsigned long start, size_t len, int flags) * If the interval [start,end) covers some unmapped address ranges, * just ignore them, but return -ENOMEM at the end. */ - down_read(¤t->mm->mmap_sem); - vma = find_vma(current->mm, start); - if (!vma) { - error = -ENOMEM; - goto out_unlock; - } - do { - unsigned long nr_pages_dirtied = 0; + down_read(&mm->mmap_sem); + vma = find_vma(mm, start); + for (;;) { struct file *file; + /* Still start < end. */ + error = -ENOMEM; + if (!vma) + goto out_unlock; /* Here start < vma->vm_end. */ if (start < vma->vm_start) { - unmapped_error = -ENOMEM; start = vma->vm_start; + if (start >= end) + goto out_unlock; + unmapped_error = -ENOMEM; } /* Here vma->vm_start <= start < vma->vm_end. */ - if (end <= vma->vm_end) { - if (start < end) { - error = msync_interval(vma, start, end, flags, - &nr_pages_dirtied); - if (error) - goto out_unlock; - } - error = unmapped_error; - done = 1; - } else { - /* Here vma->vm_start <= start < vma->vm_end < end. */ - error = msync_interval(vma, start, vma->vm_end, flags, - &nr_pages_dirtied); - if (error) - goto out_unlock; + if ((flags & MS_INVALIDATE) && + (vma->vm_flags & VM_LOCKED)) { + error = -EBUSY; + goto out_unlock; } file = vma->vm_file; start = vma->vm_end; - if ((flags & MS_ASYNC) && file && nr_pages_dirtied) { - get_file(file); - up_read(¤t->mm->mmap_sem); - balance_dirty_pages_ratelimited_nr(file->f_mapping, - nr_pages_dirtied); - fput(file); - down_read(¤t->mm->mmap_sem); - vma = find_vma(current->mm, start); - } else if ((flags & MS_SYNC) && file && + if ((flags & MS_SYNC) && file && (vma->vm_flags & VM_SHARED)) { get_file(file); - up_read(¤t->mm->mmap_sem); + up_read(&mm->mmap_sem); error = do_fsync(file, 0); fput(file); - down_read(¤t->mm->mmap_sem); - if (error) - goto out_unlock; - vma = find_vma(current->mm, start); + if (error || start >= end) + goto out; + down_read(&mm->mmap_sem); + vma = find_vma(mm, start); } else { + if (start >= end) { + error = 0; + goto out_unlock; + } vma = vma->vm_next; } - } while (vma && !done); + } out_unlock: - up_read(¤t->mm->mmap_sem); + up_read(&mm->mmap_sem); out: - return error; + return error ? : unmapped_error; } |