ACPICA: Optimize buffer allocation procedure (68e125c4) · Commits · 戴 / test

drivers/acpi/utilities/utalloc.c

+28 −25

Original line number	Diff line number	Diff line
		@@ -240,7 +240,7 @@ acpi_status
		acpi_ut_initialize_buffer(struct acpi_buffer * buffer,
		acpi_size required_length)
		{
		acpi_status status = AE_OK;
		acpi_size input_buffer_length;

		/* Parameter validation */

		@@ -248,55 +248,58 @@ acpi_ut_initialize_buffer(struct acpi_buffer * buffer,
		return (AE_BAD_PARAMETER);
		}

		switch (buffer->length) {
		/*
		* Buffer->Length is used as both an input and output parameter. Get the
		* input actual length and set the output required buffer length.
		*/
		input_buffer_length = buffer->length;
		buffer->length = required_length;

		/*
		* The input buffer length contains the actual buffer length, or the type
		* of buffer to be allocated by this routine.
		*/
		switch (input_buffer_length) {
		case ACPI_NO_BUFFER:

		/* Set the exception and returned the required length */
		/* Return the exception (and the required buffer length) */

		status = AE_BUFFER_OVERFLOW;
		break;
		return (AE_BUFFER_OVERFLOW);

		case ACPI_ALLOCATE_BUFFER:

		/* Allocate a new buffer */

		buffer->pointer = acpi_os_allocate(required_length);
		if (!buffer->pointer) {
		return (AE_NO_MEMORY);
		}

		/* Clear the buffer */

		ACPI_MEMSET(buffer->pointer, 0, required_length);
		break;

		case ACPI_ALLOCATE_LOCAL_BUFFER:

		/* Allocate a new buffer with local interface to allow tracking */

		buffer->pointer = ACPI_ALLOCATE_ZEROED(required_length);
		if (!buffer->pointer) {
		return (AE_NO_MEMORY);
		}
		buffer->pointer = ACPI_ALLOCATE(required_length);
		break;

		default:

		/* Existing buffer: Validate the size of the buffer */

		if (buffer->length < required_length) {
		status = AE_BUFFER_OVERFLOW;
		if (input_buffer_length < required_length) {
		return (AE_BUFFER_OVERFLOW);
		}
		break;
		}

		/* Clear the buffer */
		/* Validate allocation from above or input buffer pointer */

		ACPI_MEMSET(buffer->pointer, 0, required_length);
		break;
		if (!buffer->pointer) {
		return (AE_NO_MEMORY);
		}

		buffer->length = required_length;
		return (status);
		/* Have a valid buffer, clear it */

		ACPI_MEMSET(buffer->pointer, 0, required_length);
		return (AE_OK);
		}

		#ifdef NOT_USED_BY_LINUX

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