kernel: Modify the signature of k_mem_slab_free()

Modify the signature of the k_mem_slab_free() function with a new one,
replacing the old void **mem with void *mem as a parameter.

The following function:
void k_mem_slab_free(struct k_mem_slab *slab, void **mem);

has the wrong signature. mem is only used as a regular pointer, so there
is no need to use a double-pointer. The correct signature should be:
void k_mem_slab_free(struct k_mem_slab *slab, void *mem);

The issue with the current signature, although functional, is that it is
extremely confusing. I myself, a veteran Zephyr developer, was confused
by this parameter when looking at it recently.

All in-tree uses of the function have been adapted.

Fixes #61888.

Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>

drivers/audio/dmic_nrfx_pdm.c

@@ -39,7 +39,7 @@ struct dmic_nrfx_pdm_drv_cfg {
 
 static void free_buffer(struct dmic_nrfx_pdm_drv_data *drv_data, void *buffer)
 {
-	k_mem_slab_free(drv_data->mem_slab, &buffer);
+	k_mem_slab_free(drv_data->mem_slab, buffer);
 	LOG_DBG("Freed buffer %p", buffer);
 }
 

drivers/audio/mpxxdtyy-i2s.c

@@ -44,7 +44,7 @@ int mpxxdtyy_i2s_read(const struct device *dev, uint8_t stream, void **buffer,
 
 	sw_filter_lib_run(pdm_filter, pdm_block, pcm_block, pdm_size,
 			  data->pcm_mem_size);
-	k_mem_slab_free(&rx_pdm_i2s_mslab, &pdm_block);
+	k_mem_slab_free(&rx_pdm_i2s_mslab, pdm_block);
 
 	*buffer = pcm_block;
 	*size = data->pcm_mem_size;

drivers/console/uart_mcumgr.c

@@ -61,7 +61,7 @@ void uart_mcumgr_free_rx_buf(struct uart_mcumgr_rx_buf *rx_buf)
 	void *block;
 
 	block = rx_buf;
-	k_mem_slab_free(&uart_mcumgr_slab, &block);
+	k_mem_slab_free(&uart_mcumgr_slab, block);
 }
 
 #if !defined(CONFIG_MCUMGR_TRANSPORT_UART_ASYNC)

drivers/i2s/i2s_common.c

@@ -21,7 +21,7 @@ int z_impl_i2s_buf_read(const struct device *dev, void *buf, size_t *size)
 		rx_cfg = i2s_config_get((const struct device *)dev, I2S_DIR_RX);
 
 		memcpy(buf, mem_block, *size);
-		k_mem_slab_free(rx_cfg->mem_slab, &mem_block);
+		k_mem_slab_free(rx_cfg->mem_slab, mem_block);
 	}
 
 	return ret;
@@ -51,7 +51,7 @@ int z_impl_i2s_buf_write(const struct device *dev, void *buf, size_t size)
 
 	ret = i2s_write((const struct device *)dev, mem_block, size);
 	if (ret != 0) {
-		k_mem_slab_free(tx_cfg->mem_slab, &mem_block);
+		k_mem_slab_free(tx_cfg->mem_slab, mem_block);
 	}
 
 	return ret;

drivers/i2s/i2s_handlers.c

@@ -66,7 +66,7 @@ static inline int z_vrfy_i2s_buf_read(const struct device *dev,
 		copy_success = z_user_to_copy((void *)buf, mem_block,
 					      data_size);
 
-		k_mem_slab_free(rx_cfg->mem_slab, &mem_block);
+		k_mem_slab_free(rx_cfg->mem_slab, mem_block);
 		Z_OOPS(copy_success);
 		Z_OOPS(z_user_to_copy((void *)size, &data_size,
 				      sizeof(data_size)));
@@ -100,13 +100,13 @@ static inline int z_vrfy_i2s_buf_write(const struct device *dev,
 
 	ret = z_user_from_copy(mem_block, (void *)buf, size);
 	if (ret) {
-		k_mem_slab_free(tx_cfg->mem_slab, &mem_block);
+		k_mem_slab_free(tx_cfg->mem_slab, mem_block);
 		Z_OOPS(ret);
 	}
 
 	ret = i2s_write((const struct device *)dev, mem_block, size);
 	if (ret != 0) {
-		k_mem_slab_free(tx_cfg->mem_slab, &mem_block);
+		k_mem_slab_free(tx_cfg->mem_slab, mem_block);
 	}
 
 	return ret;

drivers/i2s/i2s_litex.c

@@ -588,7 +588,7 @@ static void i2s_litex_isr_tx(void *arg)
 			 stream->cfg.word_size, stream->cfg.channels);
 	i2s_clear_pending_irq(cfg->base);
 
-	k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+	k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 }
 
 static const struct i2s_driver_api i2s_litex_driver_api = {

drivers/i2s/i2s_ll_stm32.c

@@ -600,7 +600,7 @@ static void dma_tx_callback(const struct device *dma_dev, void *arg,
 	__ASSERT_NO_MSG(stream->mem_block != NULL);
 
 	/* All block data sent */
-	k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+	k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 	stream->mem_block = NULL;
 
 	/* Stop transmission if there was an error */
@@ -806,7 +806,7 @@ static void rx_stream_disable(struct stream *stream, const struct device *dev)
 
 	dma_stop(stream->dev_dma, stream->dma_channel);
 	if (stream->mem_block != NULL) {
-		k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 		stream->mem_block = NULL;
 	}
 
@@ -824,7 +824,7 @@ static void tx_stream_disable(struct stream *stream, const struct device *dev)
 
 	dma_stop(stream->dev_dma, stream->dma_channel);
 	if (stream->mem_block != NULL) {
-		k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 		stream->mem_block = NULL;
 	}
 
@@ -839,7 +839,7 @@ static void rx_queue_drop(struct stream *stream)
 	void *mem_block;
 
 	while (queue_get(&stream->mem_block_queue, &mem_block, &size) == 0) {
-		k_mem_slab_free(stream->cfg.mem_slab, &mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, mem_block);
 	}
 
 	k_sem_reset(&stream->sem);
@@ -852,7 +852,7 @@ static void tx_queue_drop(struct stream *stream)
 	unsigned int n = 0U;
 
 	while (queue_get(&stream->mem_block_queue, &mem_block, &size) == 0) {
-		k_mem_slab_free(stream->cfg.mem_slab, &mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, mem_block);
 		n++;
 	}
 

drivers/i2s/i2s_mcux_flexcomm.c

@@ -300,15 +300,15 @@ static inline void i2s_purge_stream_buffers(struct stream *stream,
 		struct i2s_txq_entry queue_entry;
 
 		while (k_msgq_get(&stream->in_queue, &queue_entry, K_NO_WAIT) == 0) {
-			k_mem_slab_free(mem_slab, &queue_entry.mem_block);
+			k_mem_slab_free(mem_slab, queue_entry.mem_block);
 		}
 	} else {
 		while (k_msgq_get(&stream->in_queue, &buffer, K_NO_WAIT) == 0) {
-			k_mem_slab_free(mem_slab, &buffer);
+			k_mem_slab_free(mem_slab, buffer);
 		}
 	}
 	while (k_msgq_get(&stream->out_queue, &buffer, K_NO_WAIT) == 0) {
-		k_mem_slab_free(mem_slab, &buffer);
+		k_mem_slab_free(mem_slab, buffer);
 	}
 }
 
@@ -457,7 +457,7 @@ static void i2s_mcux_dma_tx_callback(const struct device *dma_dev, void *arg,
 	ret = k_msgq_get(&stream->out_queue, &queue_entry.mem_block, K_NO_WAIT);
 	if (ret == 0) {
 		/* transmission complete. free the buffer */
-		k_mem_slab_free(stream->cfg.mem_slab, &queue_entry.mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, queue_entry.mem_block);
 	} else {
 		LOG_ERR("no buffer in output queue for channel %u", channel);
 	}

drivers/i2s/i2s_mcux_sai.c

@@ -124,13 +124,13 @@ static inline void i2s_purge_stream_buffers(struct stream *strm,
 
 	if (in_drop) {
 		while (k_msgq_get(&strm->in_queue, &buffer, K_NO_WAIT) == 0) {
-			k_mem_slab_free(mem_slab, &buffer);
+			k_mem_slab_free(mem_slab, buffer);
 		}
 	}
 
 	if (out_drop) {
 		while (k_msgq_get(&strm->out_queue, &buffer, K_NO_WAIT) == 0) {
-			k_mem_slab_free(mem_slab, &buffer);
+			k_mem_slab_free(mem_slab, buffer);
 		}
 	}
 }
@@ -277,7 +277,7 @@ static void i2s_dma_tx_callback(const struct device *dma_dev,
 	ret = k_msgq_get(&strm->out_queue, &buffer, K_NO_WAIT);
 	if (ret == 0) {
 		/* transmission complete. free the buffer */
-		k_mem_slab_free(strm->cfg.mem_slab, &buffer);
+		k_mem_slab_free(strm->cfg.mem_slab, buffer);
 		(strm->free_tx_dma_blocks)++;
 	} else {
 		LOG_ERR("no buf in out_queue for channel %u", channel);

drivers/i2s/i2s_nrfx.c

@@ -213,13 +213,13 @@ static bool get_next_rx_buffer(struct i2s_nrfx_drv_data *drv_data,
 static void free_tx_buffer(struct i2s_nrfx_drv_data *drv_data,
 			   const void *buffer)
 {
-	k_mem_slab_free(drv_data->tx.cfg.mem_slab, (void **)&buffer);
+	k_mem_slab_free(drv_data->tx.cfg.mem_slab, (void *)buffer);
 	LOG_DBG("Freed TX %p", buffer);
 }
 
 static void free_rx_buffer(struct i2s_nrfx_drv_data *drv_data, void *buffer)
 {
-	k_mem_slab_free(drv_data->rx.cfg.mem_slab, &buffer);
+	k_mem_slab_free(drv_data->rx.cfg.mem_slab, buffer);
 	LOG_DBG("Freed RX %p", buffer);
 }
 

drivers/i2s/i2s_sam_ssc.c

@@ -277,7 +277,7 @@ static void dma_tx_callback(const struct device *dma_dev, void *user_data,
 	__ASSERT_NO_MSG(stream->mem_block != NULL);
 
 	/* All block data sent */
-	k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+	k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 	stream->mem_block = NULL;
 
 	/* Stop transmission if there was an error */
@@ -736,7 +736,7 @@ static void rx_stream_disable(struct stream *stream, Ssc *const ssc,
 	ssc->SSC_IDR = SSC_IDR_OVRUN;
 	dma_stop(dev_dma, stream->dma_channel);
 	if (stream->mem_block != NULL) {
-		k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 		stream->mem_block = NULL;
 	}
 }
@@ -748,7 +748,7 @@ static void tx_stream_disable(struct stream *stream, Ssc *const ssc,
 	ssc->SSC_IDR = SSC_IDR_TXEMPTY;
 	dma_stop(dev_dma, stream->dma_channel);
 	if (stream->mem_block != NULL) {
-		k_mem_slab_free(stream->cfg.mem_slab, &stream->mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, stream->mem_block);
 		stream->mem_block = NULL;
 	}
 }
@@ -759,7 +759,7 @@ static void rx_queue_drop(struct stream *stream)
 	void *mem_block;
 
 	while (queue_get(&stream->mem_block_queue, &mem_block, &size) == 0) {
-		k_mem_slab_free(stream->cfg.mem_slab, &mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, mem_block);
 	}
 
 	k_sem_reset(&stream->sem);
@@ -772,7 +772,7 @@ static void tx_queue_drop(struct stream *stream)
 	unsigned int n = 0U;
 
 	while (queue_get(&stream->mem_block_queue, &mem_block, &size) == 0) {
-		k_mem_slab_free(stream->cfg.mem_slab, &mem_block);
+		k_mem_slab_free(stream->cfg.mem_slab, mem_block);
 		n++;
 	}
 

drivers/led_strip/ws2812_i2s.c

@@ -139,7 +139,7 @@ static int ws2812_strip_update_rgb(const struct device *dev, struct led_rgb *pix
 	/* Flush the buffer on the wire. */
 	ret = i2s_write(cfg->dev, mem_block, cfg->tx_buf_bytes);
 	if (ret < 0) {
-		k_mem_slab_free(cfg->mem_slab, &mem_block);
+		k_mem_slab_free(cfg->mem_slab, mem_block);
 		LOG_ERR("Failed to write data: %d", ret);
 		return ret;
 	}

drivers/modem/modem_iface_uart_async.c

@@ -48,7 +48,7 @@ static void iface_uart_async_callback(const struct device *dev,
 		break;
 	case UART_RX_BUF_RELEASED:
 		/* UART driver is done with memory, free it */
-		k_mem_slab_free(&uart_modem_async_rx_slab, (void **)&evt->data.rx_buf.buf);
+		k_mem_slab_free(&uart_modem_async_rx_slab, (void *)evt->data.rx_buf.buf);
 		break;
 	case UART_RX_RDY:
 		/* Place received data on the ring buffer */

drivers/neural_net/intel_gna.c

@@ -392,7 +392,7 @@ static int intel_gna_deregister_model(const struct device *dev,
 
 	gna_model = (struct intel_gna_model *)model_handle;
 	gna_model->registered = false;
-	k_mem_slab_free(&gna->model_slab, &model_handle);
+	k_mem_slab_free(&gna->model_slab, model_handle);
 
 	return 0;
 }

drivers/usb/device/usb_dc_nrfx.c

@@ -387,7 +387,7 @@ static inline void usbd_work_schedule(void)
  */
 static inline void usbd_evt_free(struct usbd_event *ev)
 {
-	k_mem_slab_free(&fifo_elem_slab, (void **)&ev->block.data);
+	k_mem_slab_free(&fifo_elem_slab, (void *)ev->block.data);
 }
 
 /**

drivers/usb/udc/udc_kinetis.c

@@ -506,7 +506,7 @@ static void xfer_work_handler(struct k_work *item)
 		}
 
 xfer_work_error:
-		k_mem_slab_free(&usbfsotg_ee_slab, (void **)&ev);
+		k_mem_slab_free(&usbfsotg_ee_slab, (void *)ev);
 	}
 }
 

drivers/usb/udc/udc_virtual.c

@@ -332,7 +332,7 @@ static ALWAYS_INLINE void udc_vrt_thread_handler(void *arg)
 			udc_submit_event(dev, UDC_EVT_ERROR, err);
 		}
 
-		k_mem_slab_free(&udc_vrt_slab, (void **)&vrt_ev);
+		k_mem_slab_free(&udc_vrt_slab, (void *)vrt_ev);
 	}
 }
 

drivers/usb/uhc/uhc_common.c

@@ -139,7 +139,7 @@ int uhc_xfer_free(const struct device *dev, struct uhc_transfer *const xfer)
 		uhc_xfer_buf_free(dev, buf);
 	}
 
-	k_mem_slab_free(&uhc_xfer_pool, (void **)&xfer);
+	k_mem_slab_free(&uhc_xfer_pool, (void *)xfer);
 
 xfer_free_error:
 	api->unlock(dev);

drivers/usb/uhc/uhc_virtual.c

@@ -378,7 +378,7 @@ static void xfer_work_handler(struct k_work *work)
 			}
 		}
 
-		k_mem_slab_free(&uhc_vrt_slab, (void **)&ev);
+		k_mem_slab_free(&uhc_vrt_slab, (void *)ev);
 	}
 }
 

drivers/usb/uvb/uvb.c

@@ -72,7 +72,7 @@ struct uvb_packet *uvb_alloc_pkt(const enum uvb_request request,
 
 void uvb_free_pkt(struct uvb_packet *const pkt)
 {
-	k_mem_slab_free(&uvb_pkt_slab, (void **)&pkt);
+	k_mem_slab_free(&uvb_pkt_slab, (void *)pkt);
 }
 
 static ALWAYS_INLINE int submit_new_work(struct uvb_msg *const msg)
@@ -311,7 +311,7 @@ static void uvb_work_handler(struct k_work *work)
 		break;
 	}
 
-	k_mem_slab_free(&uvb_msg_slab, (void **)&msg);
+	k_mem_slab_free(&uvb_msg_slab, (void *)msg);
 	if (!k_fifo_is_empty(&uvb_queue)) {
 		(void)k_work_submit(work);
 	}