1 files changed, 33 insertions, 15 deletions

diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 9885d1b521fe..f615c3bbb73e 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -311,24 +311,50 @@ static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd)
                    DATA_BLOCK_BITS);
 }
 
-static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap,
-                struct scatterlist *data_sg, unsigned int data_nents)
+static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
+                             bool bidi)
 {
+        struct se_cmd *se_cmd = cmd->se_cmd;
         int i, block;
         int block_remaining = 0;
         void *from, *to;
         size_t copy_bytes, from_offset;
-        struct scatterlist *sg;
+        struct scatterlist *sg, *data_sg;
+        unsigned int data_nents;
+        DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
+
+        bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
+
+        if (!bidi) {
+                data_sg = se_cmd->t_data_sg;
+                data_nents = se_cmd->t_data_nents;
+        } else {
+                uint32_t count;
+
+                /*
+                 * For bidi case, the first count blocks are for Data-Out
+                 * buffer blocks, and before gathering the Data-In buffer
+                 * the Data-Out buffer blocks should be discarded.
+                 */
+                count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
+                while (count--) {
+                        block = find_first_bit(bitmap, DATA_BLOCK_BITS);
+                        clear_bit(block, bitmap);
+                }
+
+                data_sg = se_cmd->t_bidi_data_sg;
+                data_nents = se_cmd->t_bidi_data_nents;
+        }
 
         for_each_sg(data_sg, sg, data_nents, i) {
                 int sg_remaining = sg->length;
                 to = kmap_atomic(sg_page(sg)) + sg->offset;
                 while (sg_remaining > 0) {
                         if (block_remaining == 0) {
-                                block = find_first_bit(cmd_bitmap,
+                                block = find_first_bit(bitmap,
                                                 DATA_BLOCK_BITS);
                                 block_remaining = DATA_BLOCK_SIZE;
-                                clear_bit(block, cmd_bitmap);
+                                clear_bit(block, bitmap);
                         }
                         copy_bytes = min_t(size_t, sg_remaining,
                                         block_remaining);
@@ -610,19 +636,11 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *
                                se_cmd->scsi_sense_length);
                 free_data_area(udev, cmd);
         } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
-                DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
-
                 /* Get Data-In buffer before clean up */
-                bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
-                gather_data_area(udev, bitmap,
-                        se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
+                gather_data_area(udev, cmd, true);
                 free_data_area(udev, cmd);
         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
-                DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
-
-                bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
-                gather_data_area(udev, bitmap,
-                        se_cmd->t_data_sg, se_cmd->t_data_nents);
+                gather_data_area(udev, cmd, false);
                 free_data_area(udev, cmd);
         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
                 free_data_area(udev, cmd);