ceph_sync_direct_write: stop poking into iov_iter guts

all needed primitives are there...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 23 insertions, 26 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 672b0fedb17b..f68964076c0a 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -546,7 +546,6 @@ ceph_sync_direct_write(struct kiocb *iocb, const struct iovec *iov,
         int written = 0;
         int flags;
         int check_caps = 0;
-        int page_align;
         int ret;
         struct timespec mtime = CURRENT_TIME;
         loff_t pos = iocb->ki_pos;
@@ -575,10 +574,9 @@ ceph_sync_direct_write(struct kiocb *iocb, const struct iovec *iov,
         iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
         while (iov_iter_count(&i) > 0) {
-                void __user *data = i.iov->iov_base + i.iov_offset;
-                u64 len = i.iov->iov_len - i.iov_offset;
-
-                page_align = (unsigned long)data & ~PAGE_MASK;
+                u64 len = iov_iter_single_seg_count(&i);
+                size_t start;
+                ssize_t n;
 
                 snapc = ci->i_snap_realm->cached_context;
                 vino = ceph_vino(inode);
@@ -594,20 +592,21 @@ ceph_sync_direct_write(struct kiocb *iocb, const struct iovec *iov,
                         break;
                 }
 
-                num_pages = calc_pages_for(page_align, len);
-                pages = ceph_get_direct_page_vector(data, num_pages, false);
-                if (IS_ERR(pages)) {
-                        ret = PTR_ERR(pages);
-                        goto out;
+                n = iov_iter_get_pages_alloc(&i, &pages, len, &start);
+                if (unlikely(n < 0)) {
+                        ret = n;
+                        ceph_osdc_put_request(req);
+                        break;
                 }
 
+                num_pages = (n + start + PAGE_SIZE - 1) / PAGE_SIZE;
                 /*
                  * throw out any page cache pages in this range. this
                  * may block.
                  */
                 truncate_inode_pages_range(inode->i_mapping, pos,
-                                   (pos+len) | (PAGE_CACHE_SIZE-1));
-                osd_req_op_extent_osd_data_pages(req, 0, pages, len, page_align,
+                                   (pos+n) | (PAGE_CACHE_SIZE-1));
+                osd_req_op_extent_osd_data_pages(req, 0, pages, n, start,
                                                 false, false);
 
                 /* BUG_ON(vino.snap != CEPH_NOSNAP); */
@@ -619,22 +618,20 @@ ceph_sync_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
                 ceph_put_page_vector(pages, num_pages, false);
 
-out:
                 ceph_osdc_put_request(req);
-                if (ret == 0) {
-                        pos += len;
-                        written += len;
-                        iov_iter_advance(&i, (size_t)len);
-
-                        if (pos > i_size_read(inode)) {
-                                check_caps = ceph_inode_set_size(inode, pos);
-                                if (check_caps)
-                                        ceph_check_caps(ceph_inode(inode),
-                                                        CHECK_CAPS_AUTHONLY,
-                                                        NULL);
-                        }
-                } else
+                if (ret)
                         break;
+                pos += n;
+                written += n;
+                iov_iter_advance(&i, n);
+
+                if (pos > i_size_read(inode)) {
+                        check_caps = ceph_inode_set_size(inode, pos);
+                        if (check_caps)
+                                ceph_check_caps(ceph_inode(inode),
+                                                CHECK_CAPS_AUTHONLY,
+                                                NULL);
+                }
         }
 
         if (ret != -EOLDSNAPC && written > 0) {