[PATCH net 0/3] octeontx2-af: Fix smatch reported errors

[PATCH net 0/3] octeontx2-af: Fix smatch reported errors

[Ratheesh Kannoth]

This series tightens error handling in the Marvell OcteonTX2 AF CN20K NPC
layer: MCAM paths now respect npc_mcam_idx_2_key_type() failures, debugfs
setup follows the usual "optional, do not fail init" convention, and
defrag rollback reports failure when freeing slots after a partial
allocation does not complete cleanly.

Patch 1 returns early when resolving an MCAM index to a key type fails,
so enable, configure, copy, and read paths do not program or interpret
hardware with a stale or undefined key type.

Patch 2 removes dentry and allocation-failure checks around
debugfs_create_file() in npc_cn20k_debugfs_init().  Debugfs entries are
diagnostic; callers should not abort probe or subsystem init when they
cannot be created (including when debugfs is disabled).

Patch 3 sets the error code when __npc_subbank_free() fails inside the
rollback loop in npc_defrag_alloc_free_slots(), so the function does not
return success after a failed cleanup.

Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>

Ratheesh Kannoth (3):
  octeontx2-af: npc: cn20k: Handle npc_mcam_idx_2_key_type() failures
  octeontx2-af: npc: cn20k: Drop debugfs_create_file() error checks in
    init
  octeontx2-af: npc: cn20k: Return error when defrag rollback free fails

---
 .../marvell/octeontx2/af/cn20k/debugfs.c      | 33 ++++++-------------
 .../ethernet/marvell/octeontx2/af/cn20k/npc.c | 21 +++++++++---
 2 files changed, 26 insertions(+), 28 deletions(-)

--
2.43.0

[PATCH net 1/3] octeontx2-af: npc: cn20k: Handle npc_mcam_idx_2_key_type() failures

[Ratheesh Kannoth]

npc_mcam_idx_2_key_type() can fail; ignoring its return value left
kw_type unchecked in MCAM enable, configure, copy, and read paths.
Return early on error so we do not program or interpret MCAM state
with an invalid key type.

CC: Dan Carpenter <error27@gmail.com>
Fixes: 6d1e70282f76 ("octeontx2-af: npc: cn20k: Use common APIs")
Link: https://lore.kernel.org/netdev/adiQJvuKlEhq2ILx@stanley.mountain/
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
---
 .../ethernet/marvell/octeontx2/af/cn20k/npc.c | 20 ++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
index 7291fdb89b03..2fcd0ee2b1e1 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
@@ -808,7 +808,9 @@ npc_cn20k_enable_mcam_entry(struct rvu *rvu, int blkaddr,
 	u64 cfg, hw_prio;
 	u8 kw_type;
 
-	npc_mcam_idx_2_key_type(rvu, index, &kw_type);
+	if (npc_mcam_idx_2_key_type(rvu, index, &kw_type))
+		return;
+
 	if (kw_type == NPC_MCAM_KEY_X2) {
 		cfg = rvu_read64(rvu, blkaddr,
 				 NPC_AF_CN20K_MCAMEX_BANKX_CFG_EXT(mcam_idx,
@@ -1052,10 +1054,12 @@ void npc_cn20k_config_mcam_entry(struct rvu *rvu, int blkaddr, int index,
 	int kw = 0;
 	u8 kw_type;
 
+	if (npc_mcam_idx_2_key_type(rvu, index, &kw_type))
+		return;
+
 	/* Disable before mcam entry update */
 	npc_cn20k_enable_mcam_entry(rvu, blkaddr, index, false);
 
-	npc_mcam_idx_2_key_type(rvu, index, &kw_type);
 	/* CAM1 takes the comparison value and
 	 * CAM0 specifies match for a bit in key being '0' or '1' or 'dontcare'.
 	 * CAM1<n> = 0 & CAM0<n> = 1 => match if key<n> = 0
@@ -1132,8 +1136,13 @@ void npc_cn20k_copy_mcam_entry(struct rvu *rvu, int blkaddr, u16 src, u16 dest)
 
 	dbank = npc_get_bank(mcam, dest);
 	sbank = npc_get_bank(mcam, src);
-	npc_mcam_idx_2_key_type(rvu, src, &src_kwtype);
-	npc_mcam_idx_2_key_type(rvu, dest, &dest_kwtype);
+
+	if (npc_mcam_idx_2_key_type(rvu, src, &src_kwtype))
+		return;
+
+	if (npc_mcam_idx_2_key_type(rvu, dest, &dest_kwtype))
+		return;
+
 	if (src_kwtype != dest_kwtype)
 		return;
 
@@ -1188,7 +1197,8 @@ void npc_cn20k_read_mcam_entry(struct rvu *rvu, int blkaddr, u16 index,
 	int kw = 0, bank;
 	u8 kw_type;
 
-	npc_mcam_idx_2_key_type(rvu, index, &kw_type);
+	if (npc_mcam_idx_2_key_type(rvu, index, &kw_type))
+		return;
 
 	bank = npc_get_bank(mcam, index);
 	index &= (mcam->banksize - 1);
-- 
2.43.0

[PATCH net 2/3] octeontx2-af: npc: cn20k: Drop debugfs_create_file() error checks in init

[Ratheesh Kannoth]

debugfs is not intended to be checked for allocation failures the way
other kernel APIs are: callers should not fail probe or subsystem init
because a debugfs node could not be created, including when debugfs is
disabled in Kconfig.  Replacing NULL checks with IS_ERR() checks is
similarly wrong for optional debugfs.

Remove dentry checks and -EFAULT returns from npc_cn20k_debugfs_init().
https://staticthinking.wordpress.com/2023/07/24/debugfs-functions-are-not-supposed-to-be-checked/

CC: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/netdev/adjNGPWKMOk3KgWL@stanley.mountain/
Fixes: 528530dff56b ("octeontx2-af: npc: cn20k: add debugfs support")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
---
 .../marvell/octeontx2/af/cn20k/debugfs.c      | 33 ++++++-------------
 1 file changed, 10 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/debugfs.c b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/debugfs.c
index 3debf2fae1a4..6f13296303cb 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/debugfs.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/debugfs.c
@@ -249,34 +249,21 @@ DEFINE_SHOW_ATTRIBUTE(npc_defrag);
 int npc_cn20k_debugfs_init(struct rvu *rvu)
 {
 	struct npc_priv_t *npc_priv = npc_priv_get();
-	struct dentry *npc_dentry;
 
-	npc_dentry = debugfs_create_file("mcam_layout", 0444, rvu->rvu_dbg.npc,
-					 npc_priv, &npc_mcam_layout_fops);
+	debugfs_create_file("mcam_layout", 0444, rvu->rvu_dbg.npc,
+			    npc_priv, &npc_mcam_layout_fops);
 
-	if (!npc_dentry)
-		return -EFAULT;
+	debugfs_create_file("mcam_default", 0444, rvu->rvu_dbg.npc,
+			    rvu, &npc_mcam_default_fops);
 
-	npc_dentry = debugfs_create_file("mcam_default", 0444, rvu->rvu_dbg.npc,
-					 rvu, &npc_mcam_default_fops);
+	debugfs_create_file("vidx2idx", 0444, rvu->rvu_dbg.npc,
+			    npc_priv, &npc_vidx2idx_map_fops);
 
-	if (!npc_dentry)
-		return -EFAULT;
+	debugfs_create_file("idx2vidx", 0444, rvu->rvu_dbg.npc,
+			    npc_priv, &npc_idx2vidx_map_fops);
 
-	npc_dentry = debugfs_create_file("vidx2idx", 0444, rvu->rvu_dbg.npc,
-					 npc_priv, &npc_vidx2idx_map_fops);
-	if (!npc_dentry)
-		return -EFAULT;
-
-	npc_dentry = debugfs_create_file("idx2vidx", 0444, rvu->rvu_dbg.npc,
-					 npc_priv, &npc_idx2vidx_map_fops);
-	if (!npc_dentry)
-		return -EFAULT;
-
-	npc_dentry = debugfs_create_file("defrag", 0444, rvu->rvu_dbg.npc,
-					 npc_priv, &npc_defrag_fops);
-	if (!npc_dentry)
-		return -EFAULT;
+	debugfs_create_file("defrag", 0444, rvu->rvu_dbg.npc,
+			    npc_priv, &npc_defrag_fops);
 
 	return 0;
 }
-- 
2.43.0

[PATCH net 3/3] octeontx2-af: npc: cn20k: Return error when defrag rollback free fails

[Ratheesh Kannoth]

In npc_defrag_alloc_free_slots(), the fail_free_alloc rollback loop frees
previously allocated MCAM entries after a partial allocation failure.  If
__npc_subbank_free() fails, we break out of the loop but rc was still zero
from the successful npc_mcam_idx_2_subbank_idx() lookup, so the function
incorrectly returned success.  Set rc to -EFAULT so the failure is visible
to callers.

CC: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/netdev/adjNJEpILRZATB2N@stanley.mountain/
Fixes: 645c6e3c1999 ("octeontx2-af: npc: cn20k: virtual index support")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
---
 drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
index 2fcd0ee2b1e1..df192729ac1d 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/cn20k/npc.c
@@ -3541,6 +3541,7 @@ static int npc_defrag_alloc_free_slots(struct rvu *rvu,
 			dev_err(rvu->dev,
 				"%s: Error to free mcam idx=%u\n",
 				__func__, save[i]);
+			rc = -EFAULT;
 			break;
 		}
 	}
-- 
2.43.0

Re: [PATCH net 1/3] octeontx2-af: npc: cn20k: Handle npc_mcam_idx_2_key_type() failures

[Dan Carpenter]

On Thu, Apr 16, 2026 at 09:23:50AM +0530, Ratheesh Kannoth wrote:
> npc_mcam_idx_2_key_type() can fail; ignoring its return value left
> kw_type unchecked in MCAM enable, configure, copy, and read paths.
> Return early on error so we do not program or interpret MCAM state
> with an invalid key type.
> 
> CC: Dan Carpenter <error27@gmail.com>
> Fixes: 6d1e70282f76 ("octeontx2-af: npc: cn20k: Use common APIs")
> Link: https://lore.kernel.org/netdev/adiQJvuKlEhq2ILx@stanley.mountain/
> Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>

Thanks.  That silences the uninitialized variable warning.

regards,
dan carpenter