[PATCH 6/6] scsi: target: tcmu: Make data_pages_per_blk changeable via configFS

Bodo Stroesser
2021-03-24T19:30:00Z

From: Bodo Stroesser <bstroesser@ts.fujitsu.com>

This patch makes data_pages_per_blk changeable in the same way as
it already is implemented for max_data_area_mb. This means, one
can change it typing
echo "data_pages_per_blk=N" >control
It is printed when doing
cat info

Also a new readonly attribute data_pages_per_blk delivers the
value if read.

Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
---
drivers/target/target_core_user.c | 55 +++++++++++++++++++++++++++++++++++++--
1 file changed, 53 insertions(+), 2 deletions(-)

diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 3de66db06438..eec2fd573e2b 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -2331,7 +2331,8 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level)

enum {
Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
- Opt_nl_reply_supported, Opt_max_data_area_mb, Opt_err,
+ Opt_nl_reply_supported, Opt_max_data_area_mb, Opt_data_pages_per_blk,
+ Opt_err,
};

static match_table_t tokens = {
@@ -2341,6 +2342,7 @@ static match_table_t tokens = {
{Opt_hw_max_sectors, "hw_max_sectors=%d"},
{Opt_nl_reply_supported, "nl_reply_supported=%d"},
{Opt_max_data_area_mb, "max_data_area_mb=%d"},
+ {Opt_data_pages_per_blk, "data_pages_per_blk=%d"},
{Opt_err, NULL}
};

@@ -2405,6 +2407,39 @@ static int tcmu_set_max_blocks_param(struct tcmu_dev *udev, substring_t *arg)
return ret;
}

+static int tcmu_set_data_pages_per_blk(struct tcmu_dev *udev, substring_t *arg)
+{
+ int val, ret;
+
+ ret = match_int(arg, &val);
+ if (ret < 0) {
+ pr_err("match_int() failed for data_pages_per_blk=. Error %d.\n",
+ ret);
+ return ret;
+ }
+
+ if (val > TCMU_MBS_TO_PAGES(udev->data_area_mb)) {
+ pr_err("Invalid data_pages_per_blk %d: greater than max_data_area_mb %d -> %zd pages).\n",
+ val, udev->data_area_mb,
+ TCMU_MBS_TO_PAGES(udev->data_area_mb));
+ return -EINVAL;
+ }
+
+ mutex_lock(&udev->cmdr_lock);
+ if (udev->data_bitmap) {
+ pr_err("Cannot set data_pages_per_blk after it has been enabled.\n");
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ udev->data_pages_per_blk = val;
+ udev->max_blocks = TCMU_MBS_TO_PAGES(udev->data_area_mb) / val;
+
+unlock:
+ mutex_unlock(&udev->cmdr_lock);
+ return ret;
+}
+
static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
const char *page, ssize_t count)
{
@@ -2456,6 +2491,9 @@ static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
case Opt_max_data_area_mb:
ret = tcmu_set_max_blocks_param(udev, &args[0]);
break;
+ case Opt_data_pages_per_blk:
+ ret = tcmu_set_data_pages_per_blk(udev, &args[0]);
+ break;
default:
break;
}
@@ -2476,7 +2514,8 @@ static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
bl = sprintf(b + bl, "Config: %s ",
udev->dev_config[0] ? udev->dev_config : "NULL");
bl += sprintf(b + bl, "Size: %llu ", udev->dev_size);
- bl += sprintf(b + bl, "MaxDataAreaMB: %u\n", udev->data_area_mb);
+ bl += sprintf(b + bl, "MaxDataAreaMB: %u ", udev->data_area_mb);
+ bl += sprintf(b + bl, "DataPagesPerBlk: %u\n", udev->data_pages_per_blk);

return bl;
}
@@ -2574,6 +2613,17 @@ static ssize_t tcmu_max_data_area_mb_show(struct config_item *item, char *page)
}
CONFIGFS_ATTR_RO(tcmu_, max_data_area_mb);

+static ssize_t tcmu_data_pages_per_blk_show(struct config_item *item,
+ char *page)
+{
+ struct se_dev_attrib *da = container_of(to_config_group(item),
+ struct se_dev_attrib, da_group);
+ struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
+
+ return snprintf(page, PAGE_SIZE, "%u\n", udev->data_pages_per_blk);
+}
+CONFIGFS_ATTR_RO(tcmu_, data_pages_per_blk);
+
static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
{
struct se_dev_attrib *da = container_of(to_config_group(item),
@@ -2885,6 +2935,7 @@ static struct configfs_attribute *tcmu_attrib_attrs[] = {
&tcmu_attr_cmd_time_out,
&tcmu_attr_qfull_time_out,
&tcmu_attr_max_data_area_mb,
+ &tcmu_attr_data_pages_per_blk,
&tcmu_attr_dev_config,
&tcmu_attr_dev_size,
&tcmu_attr_emulate_write_cache,
--
2.12.3