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scsi: target: tcmu: Join tcmu_cmd_get_data_length() and tcmu_cmd_get_block_cnt()

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Simplify code by joining tcmu_cmd_get_data_length() and
tcmu_cmd_get_block_cnt() into tcmu_cmd_set_block_cnts().  The new function
sets tcmu_cmd->dbi_cnt and also the new field tcmu_cmd->dbi_bidi_cnt which
is needed for further enhancements in following patches.  Simplify some
code by using tcmu_cmd->dbi(_bidi)_cnt instead of calculation from length.

Please note: The calculation of the number of dbis needed for bidi was
wrong. It was based on the length of the first bidi sg only. I changed it
to correctly sum up entire length of all bidi sgs.

Link: https://lore.kernel.org/r/20200910155041.17654-2-bstroesser@ts.fujitsu.com
Acked-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bodo Stroesser 2020-09-10 17:50:39 +02:00 committed by Martin K. Petersen
parent ed5dd6a67d
commit 52ef2743f1
1 changed files with 23 additions and 30 deletions
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53
drivers/target/target_core_user.c
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@ -177,6 +177,7 @@ struct tcmu_cmd {
/* Can't use se_cmd when cleaning up expired cmds, because if
cmd has been completed then accessing se_cmd is off limits */
uint32_t dbi_cnt;
uint32_t dbi_bidi_cnt;
uint32_t dbi_cur;
uint32_t *dbi;
@ -558,25 +559,20 @@ static inline void tcmu_free_cmd(struct tcmu_cmd *tcmu_cmd)
kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
}
static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
static inline void tcmu_cmd_set_block_cnts(struct tcmu_cmd *cmd)
{
struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
int i, len;
struct se_cmd *se_cmd = cmd->se_cmd;
cmd->dbi_cnt = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
if (se_cmd->se_cmd_flags & SCF_BIDI) {
BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
data_length += round_up(se_cmd->t_bidi_data_sg->length,
DATA_BLOCK_SIZE);
for (i = 0, len = 0; i < se_cmd->t_bidi_data_nents; i++)
len += se_cmd->t_bidi_data_sg[i].length;
cmd->dbi_bidi_cnt = DIV_ROUND_UP(len, DATA_BLOCK_SIZE);
cmd->dbi_cnt += cmd->dbi_bidi_cnt;
}
return data_length;
}
static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
{
size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
return data_length / DATA_BLOCK_SIZE;
}
static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
@ -593,8 +589,7 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
tcmu_cmd->se_cmd = se_cmd;
tcmu_cmd->tcmu_dev = udev;
tcmu_cmd_reset_dbi_cur(tcmu_cmd);
tcmu_cmd->dbi_cnt = tcmu_cmd_get_block_cnt(tcmu_cmd);
tcmu_cmd_set_block_cnts(tcmu_cmd);
tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
GFP_NOIO);
if (!tcmu_cmd->dbi) {
@ -767,13 +762,12 @@ static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
data_sg = se_cmd->t_data_sg;
data_nents = se_cmd->t_data_nents;
} else {
/*
* For bidi case, the first count blocks are for Data-Out
* buffer blocks, and before gathering the Data-In buffer
* the Data-Out buffer blocks should be discarded.
* the Data-Out buffer blocks should be skipped.
*/
count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
count = cmd->dbi_cnt - cmd->dbi_bidi_cnt;
data_sg = se_cmd->t_bidi_data_sg;
data_nents = se_cmd->t_bidi_data_nents;
@ -827,11 +821,9 @@ static inline size_t spc_bitmap_free(unsigned long *bitmap, uint32_t thresh)
* Called with ring lock held.
*/
static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
size_t cmd_size, size_t data_needed)
size_t cmd_size)
{
struct tcmu_mailbox *mb = udev->mb_addr;
uint32_t blocks_needed = (data_needed + DATA_BLOCK_SIZE - 1)
/ DATA_BLOCK_SIZE;
size_t space, cmd_needed;
u32 cmd_head;
@ -855,23 +847,23 @@ static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
return false;
}
if (!data_needed)
if (!cmd || !cmd->dbi_cnt)
return true;
/* try to check and get the data blocks as needed */
space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
if ((space * DATA_BLOCK_SIZE) < data_needed) {
if (space < cmd->dbi_cnt) {
unsigned long blocks_left =
(udev->max_blocks - udev->dbi_thresh) + space;
if (blocks_left < blocks_needed) {
if (blocks_left < cmd->dbi_cnt) {
pr_debug("no data space: only %lu available, but ask for %zu\n",
blocks_left * DATA_BLOCK_SIZE,
data_needed);
cmd->dbi_cnt * DATA_BLOCK_SIZE);
return false;
}
udev->dbi_thresh += blocks_needed;
udev->dbi_thresh += cmd->dbi_cnt;
if (udev->dbi_thresh > udev->max_blocks)
udev->dbi_thresh = udev->max_blocks;
}
@ -990,7 +982,8 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
uint32_t cmd_head;
uint64_t cdb_off;
bool copy_to_data_area;
size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
/* size of data buffer needed */
size_t data_length = (size_t)tcmu_cmd->dbi_cnt * DATA_BLOCK_SIZE;
*scsi_err = TCM_NO_SENSE;
@ -1031,7 +1024,7 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
return -1;
}
if (!is_ring_space_avail(udev, tcmu_cmd, command_size, data_length)) {
if (!is_ring_space_avail(udev, tcmu_cmd, command_size)) {
/*
* Don't leave commands partially setup because the unmap
* thread might need the blocks to make forward progress.
@ -1145,7 +1138,7 @@ queue_tmr_ring(struct tcmu_dev *udev, struct tcmu_tmr *tmr)
cmd_size = round_up(sizeof(*entry) + id_list_sz, TCMU_OP_ALIGN_SIZE);
if (!list_empty(&udev->tmr_queue) ||
!is_ring_space_avail(udev, NULL, cmd_size, 0)) {
!is_ring_space_avail(udev, NULL, cmd_size)) {
list_add_tail(&tmr->queue_entry, &udev->tmr_queue);
pr_debug("adding tmr %p on dev %s to TMR ring space wait queue\n",
tmr, udev->name);