target/user: Add support for bidirectional commands (e4648b01) · Commits · 戴 / test

Documentation/target/tcmu-design.txt

+1 −1

Original line number	Diff line number	Diff line
		@@ -152,7 +152,7 @@ overall shared memory region, not the entry. The data in/out buffers
		are accessible via tht req.iov[] array. iov_cnt contains the number of
		entries in iov[] needed to describe either the Data-In or Data-Out
		buffers. For bidirectional commands, iov_cnt specifies how many iovec
		entries cover the Data-Out area, and iov_bidi_count specifies how many
		entries cover the Data-Out area, and iov_bidi_cnt specifies how many
		iovec entries immediately after that in iov[] cover the Data-In
		area. Just like other fields, iov.iov_base is an offset from the start
		of the region.

drivers/target/target_core_user.c

+24 −5

Original line number	Diff line number	Diff line
		@@ -167,6 +167,11 @@ static struct tcmu_cmd tcmu_alloc_cmd(struct se_cmd se_cmd)
		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 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
		* 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 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
		*/
		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 @@ static void tcmu_handle_completion(struct tcmu_cmd cmd, struct tcmu_cmd_entry
		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) {

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