LU-4257 llite: fix up iov_iter implementation

[fs/lustre-release.git] / lustre / llite / llite_internal.h

diff --git a/lustre/llite/llite_internal.h b/lustre/llite/llite_internal.h
index 6c823be..f205f8a 100644 (file)
--- a/lustre/llite/llite_internal.h
+++ b/lustre/llite/llite_internal.h
@@ -1507,4 +1507,93 @@ void cl_inode_fini(struct inode *inode);
 u64 cl_fid_build_ino(const struct lu_fid *fid, int api32);
 u32 cl_fid_build_gen(const struct lu_fid *fid);
 
+#ifndef HAVE_FILE_INODE
+static inline struct inode *file_inode(struct file *file)
+{
+       return file->f_path.dentry->d_inode;
+}
+#endif
+
+#ifndef HAVE_IOV_ITER_TRUNCATE
+static inline void iov_iter_truncate(struct iov_iter *i, u64 count)
+{
+       if (i->count > count)
+               i->count = count;
+}
+#endif
+
+#ifndef HAVE_FILE_OPERATIONS_READ_WRITE_ITER
+static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
+{
+       i->count = count;
+}
+
+static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
+{
+       return (struct iovec) {
+               .iov_base = iter->iov->iov_base + iter->iov_offset,
+               .iov_len = min(iter->count,
+                              iter->iov->iov_len - iter->iov_offset),
+       };
+}
+
+#define iov_for_each(iov, iter, start)                                 \
+       for (iter = (start);                                            \
+            (iter).count && ((iov = iov_iter_iovec(&(iter))), 1);      \
+            iov_iter_advance(&(iter), (iov).iov_len))
+
+static inline ssize_t
+generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+       struct iovec iov;
+       struct iov_iter i;
+       ssize_t bytes = 0;
+
+       iov_for_each(iov, i, *iter) {
+               ssize_t res;
+
+               res = generic_file_aio_read(iocb, &iov, 1, iocb->ki_pos);
+               if (res <= 0) {
+                       if (bytes == 0)
+                               bytes = res;
+                       break;
+               }
+
+               bytes += res;
+               if (res < iov.iov_len)
+                       break;
+       }
+
+       if (bytes > 0)
+               iov_iter_advance(iter, bytes);
+       return bytes;
+}
+
+static inline ssize_t
+generic_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+       struct iovec iov;
+       struct iov_iter i;
+       ssize_t bytes = 0;
+
+       iov_for_each(iov, i, *iter) {
+               ssize_t res;
+
+               res = __generic_file_aio_write(iocb, &iov, 1, &iocb->ki_pos);
+               if (res <= 0) {
+                       if (bytes == 0)
+                               bytes = res;
+                       break;
+               }
+
+               bytes += res;
+               if (res < iov.iov_len)
+                       break;
+       }
+
+       if (bytes > 0)
+               iov_iter_advance(iter, bytes);
+       return bytes;
+}
+#endif /* HAVE_FILE_OPERATIONS_READ_WRITE_ITER */
 #endif /* LLITE_INTERNAL_H */