ceph: make readpages fully async
When we get a ->readpages() aop, submit async reads for all page ranges in the provided page list. Lock the pages immediately, so that VFS/MM will block until the reads complete. Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil
parent
c3b92c8787
commit
7c272194e6
1 changed files with 119 additions and 74 deletions
193
fs/ceph/addr.c
193
fs/ceph/addr.c
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@ -228,36 +228,128 @@ static int ceph_readpage(struct file *filp, struct page *page)
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}
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/*
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* Build a vector of contiguous pages from the provided page list.
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* Finish an async read(ahead) op.
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*/
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static struct page **page_vector_from_list(struct list_head *page_list,
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unsigned *nr_pages)
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static void finish_read(struct ceph_osd_request *req, struct ceph_msg *msg)
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{
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struct inode *inode = req->r_inode;
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struct ceph_osd_reply_head *replyhead;
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int rc, bytes;
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int i;
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/* parse reply */
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replyhead = msg->front.iov_base;
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WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
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rc = le32_to_cpu(replyhead->result);
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bytes = le32_to_cpu(msg->hdr.data_len);
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dout("finish_read %p req %p rc %d bytes %d\n", inode, req, rc, bytes);
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/* unlock all pages, zeroing any data we didn't read */
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for (i = 0; i < req->r_num_pages; i++, bytes -= PAGE_CACHE_SIZE) {
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struct page *page = req->r_pages[i];
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if (bytes < (int)PAGE_CACHE_SIZE) {
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/* zero (remainder of) page */
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int s = bytes < 0 ? 0 : bytes;
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zero_user_segment(page, s, PAGE_CACHE_SIZE);
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}
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dout("finish_read %p uptodate %p idx %lu\n", inode, page,
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page->index);
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flush_dcache_page(page);
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SetPageUptodate(page);
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unlock_page(page);
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page_cache_release(page);
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}
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kfree(req->r_pages);
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}
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/*
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* start an async read(ahead) operation. return nr_pages we submitted
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* a read for on success, or negative error code.
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*/
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static int start_read(struct inode *inode, struct list_head *page_list)
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{
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struct ceph_osd_client *osdc =
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&ceph_inode_to_client(inode)->client->osdc;
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struct ceph_inode_info *ci = ceph_inode(inode);
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struct page *page = list_entry(page_list->prev, struct page, lru);
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struct ceph_osd_request *req;
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u64 off;
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u64 len;
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int i;
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struct page **pages;
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struct page *page;
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int next_index, contig_pages = 0;
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pgoff_t next_index;
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int nr_pages = 0;
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int ret;
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off = page->index << PAGE_CACHE_SHIFT;
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/* count pages */
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next_index = page->index;
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list_for_each_entry_reverse(page, page_list, lru) {
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if (page->index != next_index)
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break;
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nr_pages++;
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next_index++;
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}
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len = nr_pages << PAGE_CACHE_SHIFT;
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dout("start_read %p nr_pages %d is %lld~%lld\n", inode, nr_pages,
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off, len);
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req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode),
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off, &len,
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CEPH_OSD_OP_READ, CEPH_OSD_FLAG_READ,
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NULL, 0,
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ci->i_truncate_seq, ci->i_truncate_size,
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NULL, false, 1, 0);
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if (!req)
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return -ENOMEM;
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/* build page vector */
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pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
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nr_pages = len >> PAGE_CACHE_SHIFT;
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pages = kmalloc(sizeof(*pages) * nr_pages, GFP_NOFS);
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ret = -ENOMEM;
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if (!pages)
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return ERR_PTR(-ENOMEM);
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BUG_ON(list_empty(page_list));
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next_index = list_entry(page_list->prev, struct page, lru)->index;
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list_for_each_entry_reverse(page, page_list, lru) {
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if (page->index == next_index) {
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dout("readpages page %d %p\n", contig_pages, page);
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pages[contig_pages] = page;
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contig_pages++;
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next_index++;
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} else {
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break;
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goto out;
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for (i = 0; i < nr_pages; ++i) {
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page = list_entry(page_list->prev, struct page, lru);
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BUG_ON(PageLocked(page));
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list_del(&page->lru);
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dout("start_read %p adding %p idx %lu\n", inode, page,
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page->index);
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if (add_to_page_cache_lru(page, &inode->i_data, page->index,
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GFP_NOFS)) {
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page_cache_release(page);
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dout("start_read %p add_to_page_cache failed %p\n",
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inode, page);
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nr_pages = i;
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goto out_pages;
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}
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pages[i] = page;
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}
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*nr_pages = contig_pages;
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return pages;
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req->r_pages = pages;
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req->r_num_pages = nr_pages;
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req->r_callback = finish_read;
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req->r_inode = inode;
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dout("start_read %p starting %p %lld~%lld\n", inode, req, off, len);
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ret = ceph_osdc_start_request(osdc, req, false);
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if (ret < 0)
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goto out_pages;
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ceph_osdc_put_request(req);
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return nr_pages;
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out_pages:
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ceph_release_page_vector(pages, nr_pages);
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kfree(pages);
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out:
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ceph_osdc_put_request(req);
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return ret;
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}
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/*
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* Read multiple pages. Leave pages we don't read + unlock in page_list;
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* the caller (VM) cleans them up.
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@ -266,64 +358,17 @@ static int ceph_readpages(struct file *file, struct address_space *mapping,
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struct list_head *page_list, unsigned nr_pages)
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{
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struct inode *inode = file->f_dentry->d_inode;
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struct ceph_inode_info *ci = ceph_inode(inode);
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struct ceph_osd_client *osdc =
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&ceph_inode_to_client(inode)->client->osdc;
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int rc = 0;
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struct page **pages;
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loff_t offset;
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u64 len;
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dout("readpages %p file %p nr_pages %d\n",
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inode, file, nr_pages);
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pages = page_vector_from_list(page_list, &nr_pages);
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if (IS_ERR(pages))
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return PTR_ERR(pages);
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/* guess read extent */
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offset = pages[0]->index << PAGE_CACHE_SHIFT;
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len = nr_pages << PAGE_CACHE_SHIFT;
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rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
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offset, &len,
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ci->i_truncate_seq, ci->i_truncate_size,
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pages, nr_pages, 0);
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if (rc == -ENOENT)
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rc = 0;
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if (rc < 0)
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goto out;
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for (; !list_empty(page_list) && len > 0;
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rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
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struct page *page =
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list_entry(page_list->prev, struct page, lru);
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list_del(&page->lru);
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if (rc < (int)PAGE_CACHE_SIZE) {
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/* zero (remainder of) page */
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int s = rc < 0 ? 0 : rc;
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zero_user_segment(page, s, PAGE_CACHE_SIZE);
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}
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if (add_to_page_cache_lru(page, mapping, page->index,
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GFP_NOFS)) {
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page_cache_release(page);
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dout("readpages %p add_to_page_cache failed %p\n",
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inode, page);
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continue;
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}
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dout("readpages %p adding %p idx %lu\n", inode, page,
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page->index);
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flush_dcache_page(page);
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SetPageUptodate(page);
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unlock_page(page);
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page_cache_release(page);
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dout("readpages %p file %p nr_pages %d\n", inode, file, nr_pages);
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while (!list_empty(page_list)) {
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rc = start_read(inode, page_list);
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if (rc < 0)
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goto out;
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BUG_ON(rc == 0);
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}
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rc = 0;
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out:
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kfree(pages);
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dout("readpages %p file %p ret %d\n", inode, file, rc);
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return rc;
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}
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