Merge "trace: ipc_logging: fix non-destructive read logic" (1fbdade1) · Commits · e / devices / android_kernel_sony_msm8994

kernel/trace/ipc_logging.c

+33 −13

Original line number	Diff line number	Diff line
		@@ -89,6 +89,30 @@ static int is_read_empty(struct ipc_log_context *ilctxt)
		ilctxt->write_page->hdr.write_offset));
		}

		/**
		* is_nd_read_equal_read - Return true if the non-destructive read is equal to
		* the destructive read
		*
		* @ilctxt: logging context
		* @returns: true if nd read is equal to read; false otherwise
		*/
		static bool is_nd_read_equal_read(struct ipc_log_context *ilctxt)
		{
		uint16_t read_offset;
		uint16_t nd_read_offset;

		if (ilctxt->nd_read_page == ilctxt->read_page) {
		read_offset = ilctxt->read_page->hdr.read_offset;
		nd_read_offset = ilctxt->nd_read_page->hdr.nd_read_offset;

		if (read_offset == nd_read_offset)
		return true;
		}

		return false;
		}


		static struct ipc_log_page get_next_page(struct ipc_log_context ilctxt,
		struct ipc_log_page *cur_pg)
		{
		@@ -158,6 +182,7 @@ static void ipc_log_drop(struct ipc_log_context ilctxt, void data,
		int data_size)
		{
		int bytes_to_read;
		bool push_nd_read;

		bytes_to_read = MIN(LOG_PAGE_DATA_SIZE
		- ilctxt->read_page->hdr.read_offset,
		@@ -168,10 +193,10 @@ static void ipc_log_drop(struct ipc_log_context ilctxt, void data,

		if (bytes_to_read != data_size) {
		/* not enough space, wrap read to next page */
		ilctxt->read_page->hdr.read_offset = 0;
		push_nd_read = is_nd_read_equal_read(ilctxt);

		if (ilctxt->nd_read_page == ilctxt->read_page) {
		/* app reading from the same page */
		ilctxt->read_page->hdr.read_offset = 0;
		if (push_nd_read) {
		ilctxt->read_page->hdr.nd_read_offset = 0;
		ilctxt->read_page = get_next_page(ilctxt,
		ilctxt->read_page);
		@@ -189,19 +214,14 @@ static void ipc_log_drop(struct ipc_log_context ilctxt, void data,

		bytes_to_read = (data_size - bytes_to_read);
		}
		ilctxt->read_page->hdr.read_offset += bytes_to_read;
		ilctxt->write_avail += data_size;

		/* update non-destructive read pointer if necessary */
		if (ilctxt->nd_read_page == ilctxt->read_page) {
		uint16_t read_offset, nd_read_offset;

		read_offset = ilctxt->read_page->hdr.read_offset;
		nd_read_offset = ilctxt->nd_read_page->hdr.nd_read_offset;
		push_nd_read = is_nd_read_equal_read(ilctxt);
		ilctxt->read_page->hdr.read_offset += bytes_to_read;
		ilctxt->write_avail += data_size;

		if (read_offset > nd_read_offset)
		ilctxt->nd_read_page->hdr.nd_read_offset = read_offset;
		}
		if (push_nd_read)
		ilctxt->nd_read_page->hdr.nd_read_offset += bytes_to_read;
		}

		/**