+int xdr_buf_read_netobj(struct xdr_buf *buf, struct xdr_netobj *obj, unsigned int offset)
+{
+ struct xdr_buf subbuf;
+
+ if (xdr_decode_word(buf, offset, &obj->len))
+ return -EFAULT;
+ if (xdr_buf_subsegment(buf, &subbuf, offset + 4, obj->len))
+ return -EFAULT;
+
+ /* Is the obj contained entirely in the head? */
+ obj->data = subbuf.head[0].iov_base;
+ if (subbuf.head[0].iov_len == obj->len)
+ return 0;
+ /* ..or is the obj contained entirely in the tail? */
+ obj->data = subbuf.tail[0].iov_base;
+ if (subbuf.tail[0].iov_len == obj->len)
+ return 0;
+
+ /* use end of tail as storage for obj:
+ * (We don't copy to the beginning because then we'd have
+ * to worry about doing a potentially overlapping copy.
+ * This assumes the object is at most half the length of the
+ * tail.) */
+ if (obj->len > buf->buflen - buf->len)
+ return -ENOMEM;
+ if (buf->tail[0].iov_len != 0)
+ obj->data = buf->tail[0].iov_base + buf->tail[0].iov_len;
+ else
+ obj->data = buf->head[0].iov_base + buf->head[0].iov_len;
+ __read_bytes_from_xdr_buf(&subbuf, obj->data, obj->len);
+ return 0;
+}
+
+/* Returns 0 on success, or else a negative error code. */
+static int
+xdr_xcode_array2(struct xdr_buf *buf, unsigned int base,
+ struct xdr_array2_desc *desc, int encode)
+{
+ char *elem = NULL, *c;
+ unsigned int copied = 0, todo, avail_here;
+ struct page **ppages = NULL;
+ int err;
+
+ if (encode) {
+ if (xdr_encode_word(buf, base, desc->array_len) != 0)
+ return -EINVAL;
+ } else {
+ if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
+ desc->array_len > desc->array_maxlen ||
+ (unsigned long) base + 4 + desc->array_len *
+ desc->elem_size > buf->len)
+ return -EINVAL;
+ }
+ base += 4;
+
+ if (!desc->xcode)
+ return 0;
+
+ todo = desc->array_len * desc->elem_size;
+
+ /* process head */
+ if (todo && base < buf->head->iov_len) {
+ c = buf->head->iov_base + base;
+ avail_here = min_t(unsigned int, todo,
+ buf->head->iov_len - base);
+ todo -= avail_here;
+
+ while (avail_here >= desc->elem_size) {
+ err = desc->xcode(desc, c);
+ if (err)
+ goto out;
+ c += desc->elem_size;
+ avail_here -= desc->elem_size;
+ }
+ if (avail_here) {
+ if (!elem) {
+ elem = kmalloc(desc->elem_size, GFP_KERNEL);
+ err = -ENOMEM;
+ if (!elem)
+ goto out;
+ }
+ if (encode) {
+ err = desc->xcode(desc, elem);
+ if (err)
+ goto out;
+ memcpy(c, elem, avail_here);
+ } else
+ memcpy(elem, c, avail_here);
+ copied = avail_here;
+ }
+ base = buf->head->iov_len; /* align to start of pages */
+ }
+
+ /* process pages array */
+ base -= buf->head->iov_len;
+ if (todo && base < buf->page_len) {
+ unsigned int avail_page;
+
+ avail_here = min(todo, buf->page_len - base);
+ todo -= avail_here;
+
+ base += buf->page_base;
+ ppages = buf->pages + (base >> PAGE_CACHE_SHIFT);
+ base &= ~PAGE_CACHE_MASK;
+ avail_page = min_t(unsigned int, PAGE_CACHE_SIZE - base,
+ avail_here);
+ c = kmap(*ppages) + base;
+
+ while (avail_here) {
+ avail_here -= avail_page;
+ if (copied || avail_page < desc->elem_size) {
+ unsigned int l = min(avail_page,
+ desc->elem_size - copied);
+ if (!elem) {
+ elem = kmalloc(desc->elem_size,
+ GFP_KERNEL);
+ err = -ENOMEM;
+ if (!elem)
+ goto out;
+ }
+ if (encode) {
+ if (!copied) {
+ err = desc->xcode(desc, elem);
+ if (err)
+ goto out;
+ }
+ memcpy(c, elem + copied, l);
+ copied += l;
+ if (copied == desc->elem_size)
+ copied = 0;
+ } else {
+ memcpy(elem + copied, c, l);
+ copied += l;
+ if (copied == desc->elem_size) {
+ err = desc->xcode(desc, elem);
+ if (err)
+ goto out;
+ copied = 0;
+ }
+ }
+ avail_page -= l;
+ c += l;
+ }
+ while (avail_page >= desc->elem_size) {
+ err = desc->xcode(desc, c);
+ if (err)
+ goto out;
+ c += desc->elem_size;
+ avail_page -= desc->elem_size;
+ }
+ if (avail_page) {
+ unsigned int l = min(avail_page,
+ desc->elem_size - copied);
+ if (!elem) {
+ elem = kmalloc(desc->elem_size,
+ GFP_KERNEL);
+ err = -ENOMEM;
+ if (!elem)
+ goto out;
+ }
+ if (encode) {
+ if (!copied) {
+ err = desc->xcode(desc, elem);
+ if (err)
+ goto out;
+ }
+ memcpy(c, elem + copied, l);
+ copied += l;
+ if (copied == desc->elem_size)
+ copied = 0;
+ } else {
+ memcpy(elem + copied, c, l);
+ copied += l;
+ if (copied == desc->elem_size) {
+ err = desc->xcode(desc, elem);
+ if (err)
+ goto out;
+ copied = 0;
+ }
+ }
+ }
+ if (avail_here) {
+ kunmap(*ppages);
+ ppages++;
+ c = kmap(*ppages);
+ }
+
+ avail_page = min(avail_here,
+ (unsigned int) PAGE_CACHE_SIZE);
+ }
+ base = buf->page_len; /* align to start of tail */
+ }
+
+ /* process tail */
+ base -= buf->page_len;
+ if (todo) {
+ c = buf->tail->iov_base + base;
+ if (copied) {
+ unsigned int l = desc->elem_size - copied;
+
+ if (encode)
+ memcpy(c, elem + copied, l);
+ else {
+ memcpy(elem + copied, c, l);
+ err = desc->xcode(desc, elem);
+ if (err)
+ goto out;
+ }
+ todo -= l;
+ c += l;
+ }
+ while (todo) {
+ err = desc->xcode(desc, c);
+ if (err)
+ goto out;
+ c += desc->elem_size;
+ todo -= desc->elem_size;
+ }
+ }
+ err = 0;
+
+out:
+ kfree(elem);
+ if (ppages)
+ kunmap(*ppages);
+ return err;
+}
+