Hi Ong,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Ong-Boon-Leong/stmmac-add-XDP-ZC-support/20210412-233847
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 5b489fea977c2b23e26e2f630478da0f4bfdc879
config: m68k-randconfig-m031-20210412 (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

New smatch warnings:
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:1587 stmmac_reinit_rx_buffers() warn: always true condition '(queue >= 0) => (0-u32max >= 0)'
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:1587 stmmac_reinit_rx_buffers() warn: always true condition '(queue >= 0) => (0-u32max >= 0)'

Old smatch warnings:
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:4423 stmmac_xdp_run_prog() error: (-2147483647) too low for ERR_PTR

vim +1587 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

  1514	
  1515	/**
  1516	 * stmmac_reinit_rx_buffers - reinit the RX descriptor buffer.
  1517	 * @priv: driver private structure
  1518	 * Description: this function is called to re-allocate a receive buffer, perform
  1519	 * the DMA mapping and init the descriptor.
  1520	 */
  1521	static void stmmac_reinit_rx_buffers(struct stmmac_priv *priv)
  1522	{
  1523		u32 rx_count = priv->plat->rx_queues_to_use;
  1524		u32 queue;
  1525		int i;
  1526	
  1527		for (queue = 0; queue < rx_count; queue++) {
  1528			struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
  1529	
  1530			for (i = 0; i < priv->dma_rx_size; i++) {
  1531				struct stmmac_rx_buffer *buf = &rx_q->buf_pool[i];
  1532	
  1533				if (buf->page) {
  1534					page_pool_recycle_direct(rx_q->page_pool, buf->page);
  1535					buf->page = NULL;
  1536				}
  1537	
  1538				if (priv->sph && buf->sec_page) {
  1539					page_pool_recycle_direct(rx_q->page_pool, buf->sec_page);
  1540					buf->sec_page = NULL;
  1541				}
  1542			}
  1543		}
  1544	
  1545		for (queue = 0; queue < rx_count; queue++) {
  1546			struct stmmac_rx_queue *rx_q = &priv->rx_queue[queue];
  1547	
  1548			for (i = 0; i < priv->dma_rx_size; i++) {
  1549				struct stmmac_rx_buffer *buf = &rx_q->buf_pool[i];
  1550				struct dma_desc *p;
  1551	
  1552				if (priv->extend_desc)
  1553					p = &((rx_q->dma_erx + i)->basic);
  1554				else
  1555					p = rx_q->dma_rx + i;
  1556	
  1557				if (!buf->page) {
  1558					buf->page = page_pool_dev_alloc_pages(rx_q->page_pool);
  1559					if (!buf->page)
  1560						goto err_reinit_rx_buffers;
  1561	
  1562					buf->addr = page_pool_get_dma_addr(buf->page) +
  1563						    buf->page_offset;
  1564				}
  1565	
  1566				if (priv->sph && !buf->sec_page) {
  1567					buf->sec_page = page_pool_dev_alloc_pages(rx_q->page_pool);
  1568					if (!buf->sec_page)
  1569						goto err_reinit_rx_buffers;
  1570	
  1571					buf->sec_addr = page_pool_get_dma_addr(buf->sec_page);
  1572				}
  1573	
  1574				stmmac_set_desc_addr(priv, p, buf->addr);
  1575				if (priv->sph)
  1576					stmmac_set_desc_sec_addr(priv, p, buf->sec_addr, true);
  1577				else
  1578					stmmac_set_desc_sec_addr(priv, p, buf->sec_addr, false);
  1579				if (priv->dma_buf_sz == BUF_SIZE_16KiB)
  1580					stmmac_init_desc3(priv, p);
  1581			}
  1582		}
  1583	
  1584		return;
  1585	
  1586	err_reinit_rx_buffers:
> 1587		while (queue >= 0) {
  1588			dma_free_rx_skbufs(priv, queue);
  1589	
  1590			if (queue == 0)
  1591				break;
  1592	
  1593			queue--;
  1594		}
  1595	}
  1596	

---
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