Commit 08976cb5 authored by Bodo Stroesser's avatar Bodo Stroesser Committed by Martin K. Petersen
Browse files

scsi: target: tcmu: Make data_pages_per_blk changeable via configfs 

Make data_pages_per_blk changeable similar to the way it is done for
max_data_area_mb. One can change the value by typing:

  echo "data_pages_per_blk=N" >control

The value is printed when doing:

  cat info

In addition, a new readonly attribute 'data_pages_per_blk' returns the
value on read.

Link: https://lore.kernel.org/r/20210324195758.2021-7-bostroesser@gmail.com


Signed-off-by: default avatarBodo Stroesser <bostroesser@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent e719afdc

drivers/target/target_core_user.c

+53 −2
Original line number Diff line number Diff line
@@ -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,