X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Fmsync.c;h=358d73cf7b78949c2e62567b1ec89d000dd2cdf7;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=2aaad0418e629c66a304ae731f3480b52db9bee1;hpb=9bf4aaab3e101692164d49b7ca357651eb691cb6;p=linux-2.6.git diff --git a/mm/msync.c b/mm/msync.c index 2aaad0418..358d73cf7 100644 --- a/mm/msync.c +++ b/mm/msync.c @@ -7,180 +7,34 @@ /* * The msync() system call. */ -#include -#include +#include #include #include -#include - -#include -#include - -/* - * Called with mm->page_table_lock held to protect against other - * threads/the swapper from ripping pte's out from under us. - */ -static int filemap_sync_pte(pte_t *ptep, struct vm_area_struct *vma, - unsigned long address, unsigned int flags) -{ - pte_t pte = *ptep; - unsigned long pfn = pte_pfn(pte); - struct page *page; - - if (pte_present(pte) && pfn_valid(pfn)) { - page = pfn_to_page(pfn); - if (!PageReserved(page) && - (ptep_clear_flush_dirty(vma, address, ptep) || - page_test_and_clear_dirty(page))) - set_page_dirty(page); - } - return 0; -} - -static int filemap_sync_pte_range(pmd_t * pmd, - unsigned long address, unsigned long end, - struct vm_area_struct *vma, unsigned int flags) -{ - pte_t *pte; - int error; - - if (pmd_none(*pmd)) - return 0; - if (pmd_bad(*pmd)) { - pmd_ERROR(*pmd); - pmd_clear(pmd); - return 0; - } - pte = pte_offset_map(pmd, address); - if ((address & PMD_MASK) != (end & PMD_MASK)) - end = (address & PMD_MASK) + PMD_SIZE; - error = 0; - do { - error |= filemap_sync_pte(pte, vma, address, flags); - address += PAGE_SIZE; - pte++; - } while (address && (address < end)); - - pte_unmap(pte - 1); - - return error; -} - -static inline int filemap_sync_pmd_range(pgd_t * pgd, - unsigned long address, unsigned long end, - struct vm_area_struct *vma, unsigned int flags) -{ - pmd_t * pmd; - int error; - - if (pgd_none(*pgd)) - return 0; - if (pgd_bad(*pgd)) { - pgd_ERROR(*pgd); - pgd_clear(pgd); - return 0; - } - pmd = pmd_offset(pgd, address); - if ((address & PGDIR_MASK) != (end & PGDIR_MASK)) - end = (address & PGDIR_MASK) + PGDIR_SIZE; - error = 0; - do { - error |= filemap_sync_pte_range(pmd, address, end, vma, flags); - address = (address + PMD_SIZE) & PMD_MASK; - pmd++; - } while (address && (address < end)); - return error; -} - -static int filemap_sync(struct vm_area_struct * vma, unsigned long address, - size_t size, unsigned int flags) -{ - pgd_t * dir; - unsigned long end = address + size; - int error = 0; - - /* Aquire the lock early; it may be possible to avoid dropping - * and reaquiring it repeatedly. - */ - spin_lock(&vma->vm_mm->page_table_lock); - - dir = pgd_offset(vma->vm_mm, address); - flush_cache_range(vma, address, end); - - /* 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 (is_vm_hugetlb_page(vma)) - goto out; - - if (address >= end) - BUG(); - do { - error |= filemap_sync_pmd_range(dir, address, end, vma, flags); - address = (address + PGDIR_SIZE) & PGDIR_MASK; - dir++; - } while (address && (address < end)); - /* - * Why flush ? filemap_sync_pte already flushed the tlbs with the - * dirty bits. - */ - flush_tlb_range(vma, end - size, end); - out: - spin_unlock(&vma->vm_mm->page_table_lock); - - return error; -} +#include +#include /* * 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 my _not_ starting I/O in MS_ASYNC we provide complete flexibility to + * 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 start, unsigned long end, int flags) -{ - int ret = 0; - struct file * file = vma->vm_file; - - if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) - return -EBUSY; - - if (file && (vma->vm_flags & VM_SHARED)) { - ret = filemap_sync(vma, start, end-start, flags); - - if (!ret && (flags & MS_SYNC)) { - struct address_space *mapping = file->f_mapping; - int err; - - down(&mapping->host->i_sem); - ret = filemap_fdatawrite(mapping); - if (file->f_op && file->f_op->fsync) { - err = file->f_op->fsync(file,file->f_dentry,1); - if (err && !ret) - ret = err; - } - err = filemap_fdatawait(mapping); - if (!ret) - ret = err; - up(&mapping->host->i_sem); - } - } - return ret; -} - asmlinkage long sys_msync(unsigned long start, size_t len, int flags) { unsigned long end; - struct vm_area_struct * vma; - int unmapped_error, error = -EINVAL; + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + int unmapped_error = 0; + int error = -EINVAL; - down_read(¤t->mm->mmap_sem); if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) goto out; if (start & ~PAGE_MASK) @@ -199,36 +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. */ - vma = find_vma(current->mm, start); - unmapped_error = 0; + down_read(&mm->mmap_sem); + vma = find_vma(mm, start); for (;;) { + struct file *file; + /* Still start < end. */ error = -ENOMEM; if (!vma) - goto out; + 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); - if (error) - goto out; - } - error = unmapped_error; - goto out; + if ((flags & MS_INVALIDATE) && + (vma->vm_flags & VM_LOCKED)) { + error = -EBUSY; + goto out_unlock; } - /* Here vma->vm_start <= start < vma->vm_end < end. */ - error = msync_interval(vma, start, vma->vm_end, flags); - if (error) - goto out; + file = vma->vm_file; start = vma->vm_end; - vma = vma->vm_next; + if ((flags & MS_SYNC) && file && + (vma->vm_flags & VM_SHARED)) { + get_file(file); + up_read(&mm->mmap_sem); + error = do_fsync(file, 0); + fput(file); + 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; + } } +out_unlock: + up_read(&mm->mmap_sem); out: - up_read(¤t->mm->mmap_sem); - return error; + return error ? : unmapped_error; }