X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=mm%2Ffilemap.c;h=90b657b50f81413a8452313f8a7b225888971f7b;hb=75ecb1a4d148b274aa9acd1d6ccaca0a4654784e;hp=100b99c2d504d9d0057267623ba90f359465c597;hpb=e245befce7af0a1e1347079ed62695b059594bd4;p=firefly-linux-kernel-4.4.55.git diff --git a/mm/filemap.c b/mm/filemap.c index 100b99c2d504..90b657b50f81 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -867,13 +867,11 @@ void do_generic_mapping_read(struct address_space *mapping, { struct inode *inode = mapping->host; unsigned long index; - unsigned long end_index; unsigned long offset; unsigned long last_index; unsigned long next_index; unsigned long prev_index; unsigned int prev_offset; - loff_t isize; struct page *cached_page; int error; struct file_ra_state ra = *_ra; @@ -886,42 +884,58 @@ void do_generic_mapping_read(struct address_space *mapping, last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; offset = *ppos & ~PAGE_CACHE_MASK; - isize = i_size_read(inode); - if (!isize) - goto out; - - end_index = (isize - 1) >> PAGE_CACHE_SHIFT; for (;;) { struct page *page; + unsigned long end_index; + loff_t isize; unsigned long nr, ret; + cond_resched(); +find_page: + page = find_get_page(mapping, index); + if (!page) { + page_cache_sync_readahead(mapping, + &ra, filp, + index, last_index - index); + page = find_get_page(mapping, index); + if (unlikely(page == NULL)) + goto no_cached_page; + } + if (PageReadahead(page)) { + page_cache_async_readahead(mapping, + &ra, filp, page, + index, last_index - index); + } + if (!PageUptodate(page)) + goto page_not_up_to_date; +page_ok: + /* + * i_size must be checked after we know the page is Uptodate. + * + * Checking i_size after the check allows us to calculate + * the correct value for "nr", which means the zero-filled + * part of the page is not copied back to userspace (unless + * another truncate extends the file - this is desired though). + */ + + isize = i_size_read(inode); + end_index = (isize - 1) >> PAGE_CACHE_SHIFT; + if (unlikely(!isize || index > end_index)) { + page_cache_release(page); + goto out; + } + /* nr is the maximum number of bytes to copy from this page */ nr = PAGE_CACHE_SIZE; - if (index >= end_index) { - if (index > end_index) - goto out; + if (index == end_index) { nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; if (nr <= offset) { + page_cache_release(page); goto out; } } nr = nr - offset; - cond_resched(); - if (index == next_index) - next_index = page_cache_readahead(mapping, &ra, filp, - index, last_index - index); - -find_page: - page = find_get_page(mapping, index); - if (unlikely(page == NULL)) { - handle_ra_miss(mapping, &ra, index); - goto no_cached_page; - } - if (!PageUptodate(page)) - goto page_not_up_to_date; -page_ok: - /* If users can be writing to this page using arbitrary * virtual addresses, take care about potential aliasing * before reading the page on the kernel side. @@ -1007,31 +1021,6 @@ readpage: unlock_page(page); } - /* - * i_size must be checked after we have done ->readpage. - * - * Checking i_size after the readpage allows us to calculate - * the correct value for "nr", which means the zero-filled - * part of the page is not copied back to userspace (unless - * another truncate extends the file - this is desired though). - */ - isize = i_size_read(inode); - end_index = (isize - 1) >> PAGE_CACHE_SHIFT; - if (unlikely(!isize || index > end_index)) { - page_cache_release(page); - goto out; - } - - /* nr is the maximum number of bytes to copy from this page */ - nr = PAGE_CACHE_SIZE; - if (index == end_index) { - nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; - if (nr <= offset) { - page_cache_release(page); - goto out; - } - } - nr = nr - offset; goto page_ok; readpage_error: @@ -1067,6 +1056,7 @@ no_cached_page: out: *_ra = ra; + _ra->prev_index = prev_index; *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; if (cached_page) @@ -1228,26 +1218,6 @@ out: } EXPORT_SYMBOL(generic_file_aio_read); -int file_send_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size) -{ - ssize_t written; - unsigned long count = desc->count; - struct file *file = desc->arg.data; - - if (size > count) - size = count; - - written = file->f_op->sendpage(file, page, offset, - size, &file->f_pos, sizeerror = written; - written = 0; - } - desc->count = count - written; - desc->written += written; - return written; -} - static ssize_t do_readahead(struct address_space *mapping, struct file *filp, unsigned long index, unsigned long nr) @@ -1317,62 +1287,62 @@ static int fastcall page_cache_read(struct file * file, unsigned long offset) #define MMAP_LOTSAMISS (100) /** - * filemap_nopage - read in file data for page fault handling - * @area: the applicable vm_area - * @address: target address to read in - * @type: returned with VM_FAULT_{MINOR,MAJOR} if not %NULL + * filemap_fault - read in file data for page fault handling + * @vma: vma in which the fault was taken + * @vmf: struct vm_fault containing details of the fault * - * filemap_nopage() is invoked via the vma operations vector for a + * filemap_fault() is invoked via the vma operations vector for a * mapped memory region to read in file data during a page fault. * * The goto's are kind of ugly, but this streamlines the normal case of having * it in the page cache, and handles the special cases reasonably without * having a lot of duplicated code. */ -struct page *filemap_nopage(struct vm_area_struct *area, - unsigned long address, int *type) +int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { int error; - struct file *file = area->vm_file; + struct file *file = vma->vm_file; struct address_space *mapping = file->f_mapping; struct file_ra_state *ra = &file->f_ra; struct inode *inode = mapping->host; struct page *page; - unsigned long size, pgoff; - int did_readaround = 0, majmin = VM_FAULT_MINOR; - - pgoff = ((address-area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff; + unsigned long size; + int did_readaround = 0; + int ret = 0; -retry_all: size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - if (pgoff >= size) + if (vmf->pgoff >= size) goto outside_data_content; /* If we don't want any read-ahead, don't bother */ - if (VM_RandomReadHint(area)) + if (VM_RandomReadHint(vma)) goto no_cached_page; - /* - * The readahead code wants to be told about each and every page - * so it can build and shrink its windows appropriately - * - * For sequential accesses, we use the generic readahead logic. - */ - if (VM_SequentialReadHint(area)) - page_cache_readahead(mapping, ra, file, pgoff, 1); - /* * Do we have something in the page cache already? */ retry_find: - page = find_get_page(mapping, pgoff); + page = find_lock_page(mapping, vmf->pgoff); + /* + * For sequential accesses, we use the generic readahead logic. + */ + if (VM_SequentialReadHint(vma)) { + if (!page) { + page_cache_sync_readahead(mapping, ra, file, + vmf->pgoff, 1); + page = find_lock_page(mapping, vmf->pgoff); + if (!page) + goto no_cached_page; + } + if (PageReadahead(page)) { + page_cache_async_readahead(mapping, ra, file, page, + vmf->pgoff, 1); + } + } + if (!page) { unsigned long ra_pages; - if (VM_SequentialReadHint(area)) { - handle_ra_miss(mapping, ra, pgoff); - goto no_cached_page; - } ra->mmap_miss++; /* @@ -1387,7 +1357,7 @@ retry_find: * check did_readaround, as this is an inner loop. */ if (!did_readaround) { - majmin = VM_FAULT_MAJOR; + ret = VM_FAULT_MAJOR; count_vm_event(PGMAJFAULT); } did_readaround = 1; @@ -1395,11 +1365,11 @@ retry_find: if (ra_pages) { pgoff_t start = 0; - if (pgoff > ra_pages / 2) - start = pgoff - ra_pages / 2; + if (vmf->pgoff > ra_pages / 2) + start = vmf->pgoff - ra_pages / 2; do_page_cache_readahead(mapping, file, start, ra_pages); } - page = find_get_page(mapping, pgoff); + page = find_lock_page(mapping, vmf->pgoff); if (!page) goto no_cached_page; } @@ -1408,35 +1378,42 @@ retry_find: ra->mmap_hit++; /* - * Ok, found a page in the page cache, now we need to check - * that it's up-to-date. + * We have a locked page in the page cache, now we need to check + * that it's up-to-date. If not, it is going to be due to an error. */ - if (!PageUptodate(page)) + if (unlikely(!PageUptodate(page))) goto page_not_uptodate; -success: + /* Must recheck i_size under page lock */ + size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + if (unlikely(vmf->pgoff >= size)) { + unlock_page(page); + goto outside_data_content; + } + /* * Found the page and have a reference on it. */ mark_page_accessed(page); - if (type) - *type = majmin; - return page; + ra->prev_index = page->index; + vmf->page = page; + return ret | VM_FAULT_LOCKED; outside_data_content: /* * An external ptracer can access pages that normally aren't * accessible.. */ - if (area->vm_mm == current->mm) - return NOPAGE_SIGBUS; + if (vma->vm_mm == current->mm) + return VM_FAULT_SIGBUS; + /* Fall through to the non-read-ahead case */ no_cached_page: /* * We're only likely to ever get here if MADV_RANDOM is in * effect. */ - error = page_cache_read(file, pgoff); + error = page_cache_read(file, vmf->pgoff); /* * The page we want has now been added to the page cache. @@ -1452,12 +1429,13 @@ no_cached_page: * to schedule I/O. */ if (error == -ENOMEM) - return NOPAGE_OOM; - return NOPAGE_SIGBUS; + return VM_FAULT_OOM; + return VM_FAULT_SIGBUS; page_not_uptodate: + /* IO error path */ if (!did_readaround) { - majmin = VM_FAULT_MAJOR; + ret = VM_FAULT_MAJOR; count_vm_event(PGMAJFAULT); } @@ -1467,217 +1445,21 @@ page_not_uptodate: * because there really aren't any performance issues here * and we need to check for errors. */ - lock_page(page); - - /* Somebody truncated the page on us? */ - if (!page->mapping) { - unlock_page(page); - page_cache_release(page); - goto retry_all; - } - - /* Somebody else successfully read it in? */ - if (PageUptodate(page)) { - unlock_page(page); - goto success; - } ClearPageError(page); error = mapping->a_ops->readpage(file, page); - if (!error) { - wait_on_page_locked(page); - if (PageUptodate(page)) - goto success; - } else if (error == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - goto retry_find; - } - - /* - * Things didn't work out. Return zero to tell the - * mm layer so, possibly freeing the page cache page first. - */ - shrink_readahead_size_eio(file, ra); page_cache_release(page); - return NOPAGE_SIGBUS; -} -EXPORT_SYMBOL(filemap_nopage); - -static struct page * filemap_getpage(struct file *file, unsigned long pgoff, - int nonblock) -{ - struct address_space *mapping = file->f_mapping; - struct page *page; - int error; - - /* - * Do we have something in the page cache already? - */ -retry_find: - page = find_get_page(mapping, pgoff); - if (!page) { - if (nonblock) - return NULL; - goto no_cached_page; - } - - /* - * Ok, found a page in the page cache, now we need to check - * that it's up-to-date. - */ - if (!PageUptodate(page)) { - if (nonblock) { - page_cache_release(page); - return NULL; - } - goto page_not_uptodate; - } - -success: - /* - * Found the page and have a reference on it. - */ - mark_page_accessed(page); - return page; -no_cached_page: - error = page_cache_read(file, pgoff); - - /* - * The page we want has now been added to the page cache. - * In the unlikely event that someone removed it in the - * meantime, we'll just come back here and read it again. - */ - if (error >= 0) + if (!error || error == AOP_TRUNCATED_PAGE) goto retry_find; - /* - * An error return from page_cache_read can result if the - * system is low on memory, or a problem occurs while trying - * to schedule I/O. - */ - return NULL; - -page_not_uptodate: - lock_page(page); - - /* Did it get truncated while we waited for it? */ - if (!page->mapping) { - unlock_page(page); - goto err; - } - - /* Did somebody else get it up-to-date? */ - if (PageUptodate(page)) { - unlock_page(page); - goto success; - } - - error = mapping->a_ops->readpage(file, page); - if (!error) { - wait_on_page_locked(page); - if (PageUptodate(page)) - goto success; - } else if (error == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - goto retry_find; - } - - /* - * Umm, take care of errors if the page isn't up-to-date. - * Try to re-read it _once_. We do this synchronously, - * because there really aren't any performance issues here - * and we need to check for errors. - */ - lock_page(page); - - /* Somebody truncated the page on us? */ - if (!page->mapping) { - unlock_page(page); - goto err; - } - /* Somebody else successfully read it in? */ - if (PageUptodate(page)) { - unlock_page(page); - goto success; - } - - ClearPageError(page); - error = mapping->a_ops->readpage(file, page); - if (!error) { - wait_on_page_locked(page); - if (PageUptodate(page)) - goto success; - } else if (error == AOP_TRUNCATED_PAGE) { - page_cache_release(page); - goto retry_find; - } - - /* - * Things didn't work out. Return zero to tell the - * mm layer so, possibly freeing the page cache page first. - */ -err: - page_cache_release(page); - - return NULL; -} - -int filemap_populate(struct vm_area_struct *vma, unsigned long addr, - unsigned long len, pgprot_t prot, unsigned long pgoff, - int nonblock) -{ - struct file *file = vma->vm_file; - struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; - unsigned long size; - struct mm_struct *mm = vma->vm_mm; - struct page *page; - int err; - - if (!nonblock) - force_page_cache_readahead(mapping, vma->vm_file, - pgoff, len >> PAGE_CACHE_SHIFT); - -repeat: - size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; - if (pgoff + (len >> PAGE_CACHE_SHIFT) > size) - return -EINVAL; - - page = filemap_getpage(file, pgoff, nonblock); - - /* XXX: This is wrong, a filesystem I/O error may have happened. Fix that as - * done in shmem_populate calling shmem_getpage */ - if (!page && !nonblock) - return -ENOMEM; - - if (page) { - err = install_page(mm, vma, addr, page, prot); - if (err) { - page_cache_release(page); - return err; - } - } else if (vma->vm_flags & VM_NONLINEAR) { - /* No page was found just because we can't read it in now (being - * here implies nonblock != 0), but the page may exist, so set - * the PTE to fault it in later. */ - err = install_file_pte(mm, vma, addr, pgoff, prot); - if (err) - return err; - } - - len -= PAGE_SIZE; - addr += PAGE_SIZE; - pgoff++; - if (len) - goto repeat; - - return 0; + /* Things didn't work out. Return zero to tell the mm layer so. */ + shrink_readahead_size_eio(file, ra); + return VM_FAULT_SIGBUS; } -EXPORT_SYMBOL(filemap_populate); +EXPORT_SYMBOL(filemap_fault); struct vm_operations_struct generic_file_vm_ops = { - .nopage = filemap_nopage, - .populate = filemap_populate, + .fault = filemap_fault, }; /* This is used for a general mmap of a disk file */ @@ -1690,6 +1472,7 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma) return -ENOEXEC; file_accessed(file); vma->vm_ops = &generic_file_vm_ops; + vma->vm_flags |= VM_CAN_NONLINEAR; return 0; }