Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f1dbd087 authored by Sheng Yang's avatar Sheng Yang Committed by Nicholas Bellinger
Browse files

target/user: Use iovec[] to describe continuous area 



We don't need use one iovec per scatter-gather list entry, since data
area are continuous.

Reviewed-by: default avatarAndy Grover <agrover@redhat.com>
Signed-off-by: default avatarSheng Yang <sheng@yasker.org>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 03a68b44

drivers/target/target_core_user.c

+26 −15
Original line number Diff line number Diff line
@@ -231,6 +231,23 @@ static inline size_t head_to_end(size_t head, size_t size) 
	return size - head;

}



static inline void new_iov(struct iovec **iov, int *iov_cnt,

			   struct tcmu_dev *udev)

{

	struct iovec *iovec;



	if (*iov_cnt != 0)

		(*iov)++;

	(*iov_cnt)++;



	iovec = *iov;

	memset(iovec, 0, sizeof(struct iovec));



	/* Even iov_base is relative to mb_addr */

	iovec->iov_base = (void __user *) udev->data_off +

		udev->data_head;

}



#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)



static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
@@ -242,6 +259,10 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 
	size_t copy_bytes;

	struct scatterlist *sg;



	if (data_nents == 0)

		return;



	new_iov(iov, iov_cnt, udev);

	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));
@@ -253,12 +274,7 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 
			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)++;

		(*iov)->iov_len += copy_bytes;



		UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
@@ -268,9 +284,8 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 


			copy_bytes = sg->length - copy_bytes;



			new_iov(iov, iov_cnt, udev);

			(*iov)->iov_len = copy_bytes;

			(*iov)->iov_base = (void __user *) udev->data_off +

							udev->data_head;



			if (copy_data) {

				to = (void *) udev->mb_addr +
@@ -279,8 +294,6 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev, 
				tcmu_flush_dcache_range(to, copy_bytes);

			}



			(*iov_cnt)++;

			(*iov)++;



			UPDATE_HEAD(udev->data_head,

				copy_bytes, udev->data_size);
@@ -393,12 +406,10 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd) 
	 * Must be a certain minimum size for response sense info, but

	 * also may be larger if the iov array is large.

	 *

	 * iovs = sgl_nents+1, for end-of-ring case, plus another 1

	 * b/c size == offsetof one-past-element.

	 * 3 iovs since we can describe the whole continuous are using one

	 * for data, one for bidi and one more in the case of wrap.

	*/

	base_command_size = max(offsetof(struct tcmu_cmd_entry,

					 req.iov[se_cmd->t_bidi_data_nents +

						 se_cmd->t_data_nents + 2]),

	base_command_size = max(offsetof(struct tcmu_cmd_entry, req.iov[3]),

				sizeof(struct tcmu_cmd_entry));

	command_size = base_command_size

		+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);