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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>
hifive-unleashed-5.1
Sheng Yang 2016-02-26 14:59:55 -08:00 committed by Nicholas Bellinger
parent 03a68b44fa
commit f1dbd087cc
1 changed files with 26 additions and 15 deletions
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41
drivers/target/target_core_user.c
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@ -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);