target/user: Add support for bidirectional commands
Enable TCMU to handle bidirectional SCSI commands. In such cases,
entries in iov[] cover both the Data-In and the Data-Out buffers. The
first iov_cnt entries correspond to the Data-Out buffer, while the
remaining iov_bidi_cnt entries correspond to the Data-In buffer.
Signed-off-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Vangelis Koukis <vkoukis@arrikto.com>
Reviewed-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 2b0d26e..60330e00 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -167,6 +167,11 @@
tcmu_cmd->tcmu_dev = udev;
tcmu_cmd->data_length = se_cmd->data_length;
+ if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
+ tcmu_cmd->data_length += se_cmd->t_bidi_data_sg->length;
+ }
+
tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
idr_preload(GFP_KERNEL);
@@ -387,7 +392,8 @@
* b/c size == offsetof one-past-element.
*/
base_command_size = max(offsetof(struct tcmu_cmd_entry,
- req.iov[se_cmd->t_data_nents + 2]),
+ req.iov[se_cmd->t_bidi_data_nents +
+ se_cmd->t_data_nents + 2]),
sizeof(struct tcmu_cmd_entry));
command_size = base_command_size
+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
@@ -456,13 +462,19 @@
*/
iov = &entry->req.iov[0];
iov_cnt = 0;
- copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE);
+ copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
+ || se_cmd->se_cmd_flags & SCF_BIDI);
alloc_and_scatter_data_area(udev, se_cmd->t_data_sg,
se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area);
entry->req.iov_cnt = iov_cnt;
- entry->req.iov_bidi_cnt = 0;
entry->req.iov_dif_cnt = 0;
+ /* Handle BIDI commands */
+ iov_cnt = 0;
+ alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
+ se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
+ entry->req.iov_bidi_cnt = iov_cnt;
+
/* All offsets relative to mb_addr, not start of entry! */
cdb_off = CMDR_OFF + cmd_head + base_command_size;
memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
@@ -535,8 +547,15 @@
se_cmd->scsi_sense_length);
UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
- }
- else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
+ } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
+ /* Discard data_out buffer */
+ UPDATE_HEAD(udev->data_tail,
+ (size_t)se_cmd->t_data_sg->length, udev->data_size);
+
+ /* Get Data-In buffer */
+ gather_and_free_data_area(udev,
+ se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
+ } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
gather_and_free_data_area(udev,
se_cmd->t_data_sg, se_cmd->t_data_nents);
} else if (se_cmd->data_direction == DMA_TO_DEVICE) {