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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: Andy Grover <agrover@redhat.com> Signed-off-by: Sheng Yang <sheng@yasker.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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parent
03a68b44fa
commit
f1dbd087cc
1 changed files with 26 additions and 15 deletions
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@ -231,6 +231,23 @@ static inline size_t head_to_end(size_t head, size_t size)
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return size - head;
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}
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static inline void new_iov(struct iovec **iov, int *iov_cnt,
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struct tcmu_dev *udev)
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{
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struct iovec *iovec;
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if (*iov_cnt != 0)
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(*iov)++;
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(*iov_cnt)++;
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iovec = *iov;
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memset(iovec, 0, sizeof(struct iovec));
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/* Even iov_base is relative to mb_addr */
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iovec->iov_base = (void __user *) udev->data_off +
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udev->data_head;
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}
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#define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
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static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
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@ -242,6 +259,10 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
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size_t copy_bytes;
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struct scatterlist *sg;
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if (data_nents == 0)
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return;
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new_iov(iov, iov_cnt, udev);
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for_each_sg(data_sg, sg, data_nents, i) {
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copy_bytes = min_t(size_t, sg->length,
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head_to_end(udev->data_head, udev->data_size));
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@ -253,12 +274,7 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
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tcmu_flush_dcache_range(to, copy_bytes);
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}
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/* Even iov_base is relative to mb_addr */
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(*iov)->iov_len = copy_bytes;
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(*iov)->iov_base = (void __user *) udev->data_off +
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udev->data_head;
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(*iov_cnt)++;
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(*iov)++;
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(*iov)->iov_len += copy_bytes;
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UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
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@ -268,9 +284,8 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
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copy_bytes = sg->length - copy_bytes;
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new_iov(iov, iov_cnt, udev);
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(*iov)->iov_len = copy_bytes;
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(*iov)->iov_base = (void __user *) udev->data_off +
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udev->data_head;
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if (copy_data) {
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to = (void *) udev->mb_addr +
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@ -279,8 +294,6 @@ static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
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tcmu_flush_dcache_range(to, copy_bytes);
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}
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(*iov_cnt)++;
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(*iov)++;
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UPDATE_HEAD(udev->data_head,
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copy_bytes, udev->data_size);
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@ -393,12 +406,10 @@ static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
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* Must be a certain minimum size for response sense info, but
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* also may be larger if the iov array is large.
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*
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* iovs = sgl_nents+1, for end-of-ring case, plus another 1
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* b/c size == offsetof one-past-element.
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* 3 iovs since we can describe the whole continuous are using one
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* for data, one for bidi and one more in the case of wrap.
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*/
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base_command_size = max(offsetof(struct tcmu_cmd_entry,
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req.iov[se_cmd->t_bidi_data_nents +
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se_cmd->t_data_nents + 2]),
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base_command_size = max(offsetof(struct tcmu_cmd_entry, req.iov[3]),
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sizeof(struct tcmu_cmd_entry));
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command_size = base_command_size
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+ round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
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