+static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
+ struct scatterlist *data_sg, unsigned int data_nents,
+ struct iovec **iov, int *iov_cnt, bool copy_data)
+{
+ int i;
+ void *from, *to;
+ size_t copy_bytes;
+ struct scatterlist *sg;
+
+ for_each_sg(data_sg, sg, data_nents, i) {
+ copy_bytes = min_t(size_t, sg->length,
+ head_to_end(udev->data_head, udev->data_size));
+ from = kmap_atomic(sg_page(sg)) + sg->offset;
+ to = (void *) udev->mb_addr + udev->data_off + udev->data_head;
+
+ if (copy_data) {
+ memcpy(to, from, copy_bytes);
+ tcmu_flush_dcache_range(to, copy_bytes);
+ }
+
+ /* Even iov_base is relative to mb_addr */
+ (*iov)->iov_len = copy_bytes;
+ (*iov)->iov_base = (void __user *) udev->data_off +
+ udev->data_head;
+ (*iov_cnt)++;
+ (*iov)++;
+
+ UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
+
+ /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */
+ if (sg->length != copy_bytes) {
+ void *from_skip = from + copy_bytes;
+
+ copy_bytes = sg->length - copy_bytes;
+
+ (*iov)->iov_len = copy_bytes;
+ (*iov)->iov_base = (void __user *) udev->data_off +
+ udev->data_head;
+
+ if (copy_data) {
+ to = (void *) udev->mb_addr +
+ udev->data_off + udev->data_head;
+ memcpy(to, from_skip, copy_bytes);
+ tcmu_flush_dcache_range(to, copy_bytes);
+ }
+
+ (*iov_cnt)++;
+ (*iov)++;
+
+ UPDATE_HEAD(udev->data_head,
+ copy_bytes, udev->data_size);
+ }
+
+ kunmap_atomic(from - sg->offset);
+ }
+}
+
+static void gather_and_free_data_area(struct tcmu_dev *udev,
+ struct scatterlist *data_sg, unsigned int data_nents)
+{
+ int i;
+ void *from, *to;
+ size_t copy_bytes;
+ struct scatterlist *sg;
+
+ /* It'd be easier to look at entry's iovec again, but UAM */
+ for_each_sg(data_sg, sg, data_nents, i) {
+ copy_bytes = min_t(size_t, sg->length,
+ head_to_end(udev->data_tail, udev->data_size));
+
+ to = kmap_atomic(sg_page(sg)) + sg->offset;
+ WARN_ON(sg->length + sg->offset > PAGE_SIZE);
+ from = (void *) udev->mb_addr +
+ udev->data_off + udev->data_tail;
+ tcmu_flush_dcache_range(from, copy_bytes);
+ memcpy(to, from, copy_bytes);
+
+ UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
+
+ /* Uh oh, wrapped the data buffer for this sg's data */
+ if (sg->length != copy_bytes) {
+ void *to_skip = to + copy_bytes;
+
+ from = (void *) udev->mb_addr +
+ udev->data_off + udev->data_tail;
+ WARN_ON(udev->data_tail);
+ copy_bytes = sg->length - copy_bytes;
+ tcmu_flush_dcache_range(from, copy_bytes);
+ memcpy(to_skip, from, copy_bytes);
+
+ UPDATE_HEAD(udev->data_tail,
+ copy_bytes, udev->data_size);
+ }
+ kunmap_atomic(to - sg->offset);
+ }
+}
+