Merge branch 'fix-sparse-warnings-in-dpaa_eth-driver'

Vladimir Oltean says:

====================
Fix sparse warnings in dpaa_eth driver

This is a follow-up of the discussion at:
https://lore.kernel.org/oe-kbuild-all/20241028-sticky-refined-lionfish-b06c0c@leitao/
where I said I would take care of the sparse warnings uncovered by
Breno's COMPILE_TEST change for the dpaa_eth driver.

There was one warning that I decided to treat as an actual bug:
https://lore.kernel.org/netdev/20241029163105.44135-1-vladimir.oltean@nxp.com/
and what remains here are those warnings which I consider harmless.

I would like Christophe to ack the entire series to be taken through
netdev. I find it weird that the qbman driver, whose major API consumer
is netdev, is maintained by a different group. In this case, the buggy
qm_sg_entry_get_off() function is defined in qbman but exclusively
called in netdev.
====================

Link: https://patch.msgid.link/20241029164317.50182-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 17 insertions, 11 deletions

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index ac06b01fe9340..bf5baef5c3e06 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -1820,7 +1820,6 @@ static struct sk_buff *sg_fd_to_skb(const struct dpaa_priv *priv,
 	struct page *page, *head_page;
 	struct dpaa_bp *dpaa_bp;
 	void *vaddr, *sg_vaddr;
-	int frag_off, frag_len;
 	struct sk_buff *skb;
 	dma_addr_t sg_addr;
 	int page_offset;
@@ -1863,6 +1862,11 @@ static struct sk_buff *sg_fd_to_skb(const struct dpaa_priv *priv,
 			 * on Tx, if extra headers are added.
 			 */
 			WARN_ON(fd_off != priv->rx_headroom);
+			/* The offset to data start within the buffer holding
+			 * the SGT should always be equal to the offset to data
+			 * start within the first buffer holding the frame.
+			 */
+			WARN_ON_ONCE(fd_off != qm_sg_entry_get_off(&sgt[i]));
 			skb_reserve(skb, fd_off);
 			skb_put(skb, qm_sg_entry_get_len(&sgt[i]));
 		} else {
@@ -1876,21 +1880,23 @@ static struct sk_buff *sg_fd_to_skb(const struct dpaa_priv *priv,
 			page = virt_to_page(sg_vaddr);
 			head_page = virt_to_head_page(sg_vaddr);
 
-			/* Compute offset in (possibly tail) page */
+			/* Compute offset of sg_vaddr in (possibly tail) page */
 			page_offset = ((unsigned long)sg_vaddr &
 					(PAGE_SIZE - 1)) +
 				(page_address(page) - page_address(head_page));
-			/* page_offset only refers to the beginning of sgt[i];
-			 * but the buffer itself may have an internal offset.
+
+			/* Non-initial SGT entries should not have a buffer
+			 * offset.
 			 */
-			frag_off = qm_sg_entry_get_off(&sgt[i]) + page_offset;
-			frag_len = qm_sg_entry_get_len(&sgt[i]);
+			WARN_ON_ONCE(qm_sg_entry_get_off(&sgt[i]));
+
 			/* skb_add_rx_frag() does no checking on the page; if
 			 * we pass it a tail page, we'll end up with
-			 * bad page accounting and eventually with segafults.
+			 * bad page accounting and eventually with segfaults.
 			 */
-			skb_add_rx_frag(skb, i - 1, head_page, frag_off,
-					frag_len, dpaa_bp->size);
+			skb_add_rx_frag(skb, i - 1, head_page, page_offset,
+					qm_sg_entry_get_len(&sgt[i]),
+					dpaa_bp->size);
 		}
 
 		/* Update the pool count for the current {cpu x bpool} */
@@ -2766,7 +2772,7 @@ static enum qman_cb_dqrr_result rx_default_dqrr(struct qman_portal *portal,
 	if (net_dev->features & NETIF_F_RXHASH && priv->keygen_in_use &&
 	    !fman_port_get_hash_result_offset(priv->mac_dev->port[RX],
 					      &hash_offset)) {
-		hash = be32_to_cpu(*(u32 *)(vaddr + hash_offset));
+		hash = be32_to_cpu(*(__be32 *)(vaddr + hash_offset));
 		hash_valid = true;
 	}
 
diff --git a/include/soc/fsl/qman.h b/include/soc/fsl/qman.h
index 0d3d6beb7fdbd..7f7a4932d7f10 100644
--- a/include/soc/fsl/qman.h
+++ b/include/soc/fsl/qman.h
@@ -242,7 +242,7 @@ static inline void qm_sg_entry_set_f(struct qm_sg_entry *sg, int len)
 
 static inline int qm_sg_entry_get_off(const struct qm_sg_entry *sg)
 {
-	return be32_to_cpu(sg->offset) & QM_SG_OFF_MASK;
+	return be16_to_cpu(sg->offset) & QM_SG_OFF_MASK;
 }
 
 /* "Frame Dequeue Response" */