Commit 7ef85f5f authored by Jarkko Nikula's avatar Jarkko Nikula Committed by Wolfram Sang
Browse files

i2c: core: Reduce stack size of acpi_i2c_space_handler() 



sizeof(struct i2c_client) is 1088 bytes on a CONFIG_X86_64=y build and
produces following warning when CONFIG_FRAME_WARN is set to 1024:

drivers/i2c/i2c-core.c: In function ‘acpi_i2c_space_handler’:
drivers/i2c/i2c-core.c:367:1: warning: the frame size of 1152 bytes is
larger than 1024 bytes [-Wframe-larger-than=]

This is not critical given that kernel stack is 16 kB on x86_64 but lets
reduce the stack usage by allocating the struct i2c_client from the heap.

Signed-off-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent edc9102a

drivers/i2c/i2c-core.c

+21 −16
Original line number Diff line number Diff line
@@ -258,7 +258,7 @@ acpi_i2c_space_handler(u32 function, acpi_physical_address command, 
	struct acpi_connection_info *info = &data->info;

	struct acpi_resource_i2c_serialbus *sb;

	struct i2c_adapter *adapter = data->adapter;

	struct i2c_client client;

	struct i2c_client *client;

	struct acpi_resource *ares;

	u32 accessor_type = function >> 16;

	u8 action = function & ACPI_IO_MASK;
@@ -269,6 +269,12 @@ acpi_i2c_space_handler(u32 function, acpi_physical_address command, 
	if (ACPI_FAILURE(ret))

		return ret;



	client = kzalloc(sizeof(*client), GFP_KERNEL);

	if (!client) {

		ret = AE_NO_MEMORY;

		goto err;

	}



	if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {

		ret = AE_BAD_PARAMETER;

		goto err;
@@ -280,75 +286,73 @@ acpi_i2c_space_handler(u32 function, acpi_physical_address command, 
		goto err;

	}



	memset(&client, 0, sizeof(client));

	client.adapter = adapter;

	client.addr = sb->slave_address;

	client.flags = 0;

	client->adapter = adapter;

	client->addr = sb->slave_address;



	if (sb->access_mode == ACPI_I2C_10BIT_MODE)

		client.flags |= I2C_CLIENT_TEN;

		client->flags |= I2C_CLIENT_TEN;



	switch (accessor_type) {

	case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:

		if (action == ACPI_READ) {

			status = i2c_smbus_read_byte(&client);

			status = i2c_smbus_read_byte(client);

			if (status >= 0) {

				gsb->bdata = status;

				status = 0;

			}

		} else {

			status = i2c_smbus_write_byte(&client, gsb->bdata);

			status = i2c_smbus_write_byte(client, gsb->bdata);

		}

		break;



	case ACPI_GSB_ACCESS_ATTRIB_BYTE:

		if (action == ACPI_READ) {

			status = i2c_smbus_read_byte_data(&client, command);

			status = i2c_smbus_read_byte_data(client, command);

			if (status >= 0) {

				gsb->bdata = status;

				status = 0;

			}

		} else {

			status = i2c_smbus_write_byte_data(&client, command,

			status = i2c_smbus_write_byte_data(client, command,

					gsb->bdata);

		}

		break;



	case ACPI_GSB_ACCESS_ATTRIB_WORD:

		if (action == ACPI_READ) {

			status = i2c_smbus_read_word_data(&client, command);

			status = i2c_smbus_read_word_data(client, command);

			if (status >= 0) {

				gsb->wdata = status;

				status = 0;

			}

		} else {

			status = i2c_smbus_write_word_data(&client, command,

			status = i2c_smbus_write_word_data(client, command,

					gsb->wdata);

		}

		break;



	case ACPI_GSB_ACCESS_ATTRIB_BLOCK:

		if (action == ACPI_READ) {

			status = i2c_smbus_read_block_data(&client, command,

			status = i2c_smbus_read_block_data(client, command,

					gsb->data);

			if (status >= 0) {

				gsb->len = status;

				status = 0;

			}

		} else {

			status = i2c_smbus_write_block_data(&client, command,

			status = i2c_smbus_write_block_data(client, command,

					gsb->len, gsb->data);

		}

		break;



	case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:

		if (action == ACPI_READ) {

			status = acpi_gsb_i2c_read_bytes(&client, command,

			status = acpi_gsb_i2c_read_bytes(client, command,

					gsb->data, info->access_length);

			if (status > 0)

				status = 0;

		} else {

			status = acpi_gsb_i2c_write_bytes(&client, command,

			status = acpi_gsb_i2c_write_bytes(client, command,

					gsb->data, info->access_length);

		}

		break;
@@ -362,6 +366,7 @@ acpi_i2c_space_handler(u32 function, acpi_physical_address command, 
	gsb->status = status;



 err:

	kfree(client);

	ACPI_FREE(ares);

	return ret;

}

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