ceph_aio_read(): keep iov_iter across retries

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

1 files changed, 8 insertions, 6 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 21a56c27b74c..d8f383d59449 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -806,6 +806,9 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
         ssize_t ret;
         int want, got = 0;
         int checkeof = 0, read = 0;
+        struct iov_iter i;
+
+        iov_iter_init(&i, iov, nr_segs, len, 0);
 
 again:
         dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
@@ -822,28 +825,26 @@ again:
         if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
             (iocb->ki_filp->f_flags & O_DIRECT) ||
             (fi->flags & CEPH_F_SYNC)) {
-                struct iov_iter i;
 
                 dout("aio_sync_read %p %llx.%llx %llu~%u got cap refs on %s\n",
                      inode, ceph_vinop(inode), iocb->ki_pos, (unsigned)len,
                      ceph_cap_string(got));
 
-                if (!read)
-                        len = iov_length(iov, nr_segs);
-
-                iov_iter_init(&i, iov, nr_segs, len, read);
-
                 /* hmm, this isn't really async... */
                 ret = ceph_sync_read(iocb, &i, &checkeof);
         } else {
                 /*
                  * We can't modify the content of iov,
                  * so we only read from beginning.
+                 *
+                 * When we switch generic_file_aio_read() to iov_iter, the
+                 * if () below will be removed -- AV
                  */
                 if (read) {
                         iocb->ki_pos = pos;
                         len = iocb->ki_nbytes;
                         read = 0;
+                        iov_iter_init(&i, iov, nr_segs, len, 0);
                 }
                 dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
                      inode, ceph_vinop(inode), pos, (unsigned)len,
@@ -866,6 +867,7 @@ again:
                              ", reading more\n", iocb->ki_pos,
                              inode->i_size);
 
+                        iov_iter_advance(&i, ret);
                         read += ret;
                         len -= ret;
                         checkeof = 0;