[PATCH v3 7/7] scsi: mvsas: Use sas_task_find_rq() for tagging

John Garry
2022-10-04T10:57:43Z

The request associated with a scsi command coming from the block layer
has a unique tag, so use that when possible for getting a slot.

Unfortunately we don't support reserved commands in the SCSI midlayer yet.
As such, SMP tasks - as an example - will not have a request associated, so
in the interim continue to manage those tags for that type of sas_task
internally.

We reserve an arbitrary 4 tags for these internal tags. Indeed, we already
decrement MVS_RSVD_SLOTS by 2 for the shost can_queue when flag
MVF_FLAG_SOC is set. This change was made in commit 20b09c2992fef
("[PATCH] [SCSI] mvsas: add support for 94xx; layout change; bug fixes"),
but what those 2 slots are used for is not obvious.

Also make the tag management functions static, where possible.

Signed-off-by: John Garry <john.garry@huawei.com>
---
drivers/scsi/mvsas/mv_defs.h | 1 +
drivers/scsi/mvsas/mv_init.c | 9 +++++----
drivers/scsi/mvsas/mv_sas.c | 35 ++++++++++++++++++++++-------------
drivers/scsi/mvsas/mv_sas.h | 7 +------
4 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/mvsas/mv_defs.h b/drivers/scsi/mvsas/mv_defs.h
index 7123a2efbf58..8ef174cd4d37 100644
--- a/drivers/scsi/mvsas/mv_defs.h
+++ b/drivers/scsi/mvsas/mv_defs.h
@@ -40,6 +40,7 @@ enum driver_configuration {
MVS_ATA_CMD_SZ = 96, /* SATA command table buffer size */
MVS_OAF_SZ = 64, /* Open address frame buffer size */
MVS_QUEUE_SIZE = 64, /* Support Queue depth */
+ MVS_RSVD_SLOTS = 4,
MVS_SOC_CAN_QUEUE = MVS_SOC_SLOTS - 2,
};

diff --git a/drivers/scsi/mvsas/mv_init.c b/drivers/scsi/mvsas/mv_init.c
index c85fb812ad43..cfe84473a515 100644
--- a/drivers/scsi/mvsas/mv_init.c
+++ b/drivers/scsi/mvsas/mv_init.c
@@ -142,7 +142,7 @@ static void mvs_free(struct mvs_info *mvi)
scsi_host_put(mvi->shost);
list_for_each_entry(mwq, &mvi->wq_list, entry)
cancel_delayed_work(&mwq->work_q);
- kfree(mvi->tags);
+ kfree(mvi->rsvd_tags);
kfree(mvi);
}

@@ -284,7 +284,6 @@ static int mvs_alloc(struct mvs_info *mvi, struct Scsi_Host *shost)
printk(KERN_DEBUG "failed to create dma pool %s.\n", pool_name);
goto err_out;
}
- mvi->tags_num = slot_nr;

return 0;
err_out:
@@ -367,8 +366,8 @@ static struct mvs_info *mvs_pci_alloc(struct pci_dev *pdev,
mvi->sas = sha;
mvi->shost = shost;

- mvi->tags = kzalloc(MVS_CHIP_SLOT_SZ>>3, GFP_KERNEL);
- if (!mvi->tags)
+ mvi->rsvd_tags = bitmap_zalloc(MVS_RSVD_SLOTS, GFP_KERNEL);
+ if (!mvi->rsvd_tags)
goto err_out;

if (MVS_CHIP_DISP->chip_ioremap(mvi))
@@ -469,6 +468,8 @@ static void mvs_post_sas_ha_init(struct Scsi_Host *shost,
else
can_queue = MVS_CHIP_SLOT_SZ;

+ can_queue -= MVS_RSVD_SLOTS;
+
shost->sg_tablesize = min_t(u16, SG_ALL, MVS_MAX_SG);
shost->can_queue = can_queue;
mvi->shost->cmd_per_lun = MVS_QUEUE_SIZE;
diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c
index 0810e6c930e1..3d96aec6a7c8 100644
--- a/drivers/scsi/mvsas/mv_sas.c
+++ b/drivers/scsi/mvsas/mv_sas.c
@@ -20,31 +20,34 @@ static int mvs_find_tag(struct mvs_info *mvi, struct sas_task *task, u32 *tag)
return 0;
}

-void mvs_tag_clear(struct mvs_info *mvi, u32 tag)
+static void mvs_tag_clear(struct mvs_info *mvi, u32 tag)
{
- void *bitmap = mvi->tags;
+ void *bitmap = mvi->rsvd_tags;
clear_bit(tag, bitmap);
}

-void mvs_tag_free(struct mvs_info *mvi, u32 tag)
+static void mvs_tag_free(struct mvs_info *mvi, u32 tag)
{
+ if (tag >= MVS_RSVD_SLOTS)
+ return;
+
mvs_tag_clear(mvi, tag);
}

-void mvs_tag_set(struct mvs_info *mvi, unsigned int tag)
+static void mvs_tag_set(struct mvs_info *mvi, unsigned int tag)
{
- void *bitmap = mvi->tags;
+ void *bitmap = mvi->rsvd_tags;
set_bit(tag, bitmap);
}

-inline int mvs_tag_alloc(struct mvs_info *mvi, u32 *tag_out)
+static int mvs_tag_alloc(struct mvs_info *mvi, u32 *tag_out)
{
unsigned int index, tag;
- void *bitmap = mvi->tags;
+ void *bitmap = mvi->rsvd_tags;

- index = find_first_zero_bit(bitmap, mvi->tags_num);
+ index = find_first_zero_bit(bitmap, MVS_RSVD_SLOTS);
tag = index;
- if (tag >= mvi->tags_num)
+ if (tag >= MVS_RSVD_SLOTS)
return -SAS_QUEUE_FULL;
mvs_tag_set(mvi, tag);
*tag_out = tag;
@@ -696,6 +699,7 @@ static int mvs_task_prep(struct sas_task *task, struct mvs_info *mvi, int is_tmf
struct mvs_task_exec_info tei;
struct mvs_slot_info *slot;
u32 tag = 0xdeadbeef, n_elem = 0;
+ struct request *rq;
int rc = 0;

if (!dev->port) {
@@ -760,9 +764,14 @@ static int mvs_task_prep(struct sas_task *task, struct mvs_info *mvi, int is_tmf
n_elem = task->num_scatter;
}

- rc = mvs_tag_alloc(mvi, &tag);
- if (rc)
- goto err_out;
+ rq = sas_task_find_rq(task);
+ if (rq) {
+ tag = rq->tag + MVS_RSVD_SLOTS;
+ } else {
+ rc = mvs_tag_alloc(mvi, &tag);
+ if (rc)
+ goto err_out;
+ }

slot = &mvi->slot_info[tag];

@@ -857,7 +866,7 @@ int mvs_queue_command(struct sas_task *task, gfp_t gfp_flags)
static void mvs_slot_free(struct mvs_info *mvi, u32 rx_desc)
{
u32 slot_idx = rx_desc & RXQ_SLOT_MASK;
- mvs_tag_clear(mvi, slot_idx);
+ mvs_tag_free(mvi, slot_idx);
}

static void mvs_slot_task_free(struct mvs_info *mvi, struct sas_task *task,
diff --git a/drivers/scsi/mvsas/mv_sas.h b/drivers/scsi/mvsas/mv_sas.h
index fe57665bdb50..68df771e2975 100644
--- a/drivers/scsi/mvsas/mv_sas.h
+++ b/drivers/scsi/mvsas/mv_sas.h
@@ -370,8 +370,7 @@ struct mvs_info {
u32 chip_id;
const struct mvs_chip_info *chip;

- int tags_num;
- unsigned long *tags;
+ unsigned long *rsvd_tags;
/* further per-slot information */
struct mvs_phy phy[MVS_MAX_PHYS];
struct mvs_port port[MVS_MAX_PHYS];
@@ -424,10 +423,6 @@ struct mvs_task_exec_info {

/******************** function prototype *********************/
void mvs_get_sas_addr(void *buf, u32 buflen);
-void mvs_tag_clear(struct mvs_info *mvi, u32 tag);
-void mvs_tag_free(struct mvs_info *mvi, u32 tag);
-void mvs_tag_set(struct mvs_info *mvi, unsigned int tag);
-int mvs_tag_alloc(struct mvs_info *mvi, u32 *tag_out);
void mvs_iounmap(void __iomem *regs);
int mvs_ioremap(struct mvs_info *mvi, int bar, int bar_ex);
void mvs_phys_reset(struct mvs_info *mvi, u32 phy_mask, int hard);
--
2.25.1