5.15-stable review patch. If anyone has any objections, please let me know.

------------------

From: Nishanth Menon nm@ti.com

[ Upstream commit 90a88306eb874fe4bbdd860e6c9787f5bbc588b5 ]

Make knav_dma_open_channel consistently return NULL on error instead of ERR_PTR. Currently the header include/linux/soc/ti/knav_dma.h returns NULL when the driver is disabled, but the driver implementation does not even return NULL or ERR_PTR on failure, causing inconsistency in the users. This results in a crash in netcp_free_navigator_resources as followed (trimmed):

Unhandled fault: alignment exception (0x221) at 0xfffffff2 [fffffff2] *pgd=80000800207003, *pmd=82ffda003, *pte=00000000 Internal error: : 221 [#1] SMP ARM Modules linked in: CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.17.0-rc7 #1 NONE Hardware name: Keystone PC is at knav_dma_close_channel+0x30/0x19c LR is at netcp_free_navigator_resources+0x2c/0x28c

[... TRIM...]

Call trace: knav_dma_close_channel from netcp_free_navigator_resources+0x2c/0x28c netcp_free_navigator_resources from netcp_ndo_open+0x430/0x46c netcp_ndo_open from __dev_open+0x114/0x29c __dev_open from __dev_change_flags+0x190/0x208 __dev_change_flags from netif_change_flags+0x1c/0x58 netif_change_flags from dev_change_flags+0x38/0xa0 dev_change_flags from ip_auto_config+0x2c4/0x11f0 ip_auto_config from do_one_initcall+0x58/0x200 do_one_initcall from kernel_init_freeable+0x1cc/0x238 kernel_init_freeable from kernel_init+0x1c/0x12c kernel_init from ret_from_fork+0x14/0x38 [... TRIM...]

Standardize the error handling by making the function return NULL on all error conditions. The API is used in just the netcp_core.c so the impact is limited.

Note, this change, in effect reverts commit 5b6cb43b4d62 ("net: ethernet: ti: netcp_core: return error while dma channel open issue"), but provides a less error prone implementation.

Suggested-by: Simon Horman horms@kernel.org Suggested-by: Jacob Keller jacob.e.keller@intel.com Signed-off-by: Nishanth Menon nm@ti.com Reviewed-by: Jacob Keller jacob.e.keller@intel.com Link: https://patch.msgid.link/20251103162811.3730055-1-nm@ti.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/ti/netcp_core.c | 10 +++++----- drivers/soc/ti/knav_dma.c | 14 +++++++------- 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c index 2f00be789a8a9..08c6cb16532e5 100644 --- a/drivers/net/ethernet/ti/netcp_core.c +++ b/drivers/net/ethernet/ti/netcp_core.c @@ -1338,10 +1338,10 @@ int netcp_txpipe_open(struct netcp_tx_pipe *tx_pipe)

tx_pipe->dma_channel = knav_dma_open_channel(dev, tx_pipe->dma_chan_name, &config); - if (IS_ERR(tx_pipe->dma_channel)) { + if (!tx_pipe->dma_channel) { dev_err(dev, "failed opening tx chan(%s)\n", tx_pipe->dma_chan_name); - ret = PTR_ERR(tx_pipe->dma_channel); + ret = -EINVAL; goto err; }

@@ -1359,7 +1359,7 @@ int netcp_txpipe_open(struct netcp_tx_pipe *tx_pipe) return 0;

err: - if (!IS_ERR_OR_NULL(tx_pipe->dma_channel)) + if (tx_pipe->dma_channel) knav_dma_close_channel(tx_pipe->dma_channel); tx_pipe->dma_channel = NULL; return ret; @@ -1678,10 +1678,10 @@ static int netcp_setup_navigator_resources(struct net_device *ndev)

netcp->rx_channel = knav_dma_open_channel(netcp->netcp_device->device, netcp->dma_chan_name, &config); - if (IS_ERR(netcp->rx_channel)) { + if (!netcp->rx_channel) { dev_err(netcp->ndev_dev, "failed opening rx chan(%s\n", netcp->dma_chan_name); - ret = PTR_ERR(netcp->rx_channel); + ret = -EINVAL; goto fail; }

diff --git a/drivers/soc/ti/knav_dma.c b/drivers/soc/ti/knav_dma.c index 591d14ebcb112..bbde54b2ce62d 100644 --- a/drivers/soc/ti/knav_dma.c +++ b/drivers/soc/ti/knav_dma.c @@ -410,7 +410,7 @@ static int of_channel_match_helper(struct device_node *np, const char *name, * @name: slave channel name * @config: dma configuration parameters * - * Returns pointer to appropriate DMA channel on success or error. + * Return: Pointer to appropriate DMA channel on success or NULL on error. */ void *knav_dma_open_channel(struct device *dev, const char *name, struct knav_dma_cfg *config) @@ -423,13 +423,13 @@ void *knav_dma_open_channel(struct device *dev, const char *name,

if (!kdev) { pr_err("keystone-navigator-dma driver not registered\n"); - return (void *)-EINVAL; + return NULL; }

chan_num = of_channel_match_helper(dev->of_node, name, &instance); if (chan_num < 0) { dev_err(kdev->dev, "No DMA instance with name %s\n", name); - return (void *)-EINVAL; + return NULL; }

dev_dbg(kdev->dev, "initializing %s channel %d from DMA %s\n", @@ -440,7 +440,7 @@ void *knav_dma_open_channel(struct device *dev, const char *name, if (config->direction != DMA_MEM_TO_DEV && config->direction != DMA_DEV_TO_MEM) { dev_err(kdev->dev, "bad direction\n"); - return (void *)-EINVAL; + return NULL; }

/* Look for correct dma instance */ @@ -452,7 +452,7 @@ void *knav_dma_open_channel(struct device *dev, const char *name, } if (!found) { dev_err(kdev->dev, "No DMA instance with name %s\n", instance); - return (void *)-EINVAL; + return NULL; }

/* Look for correct dma channel from dma instance */ @@ -473,14 +473,14 @@ void *knav_dma_open_channel(struct device *dev, const char *name, if (!found) { dev_err(kdev->dev, "channel %d is not in DMA %s\n", chan_num, instance); - return (void *)-EINVAL; + return NULL; }

if (atomic_read(&chan->ref_count) >= 1) { if (!check_config(chan, config)) { dev_err(kdev->dev, "channel %d config miss-match\n", chan_num); - return (void *)-EINVAL; + return NULL; } }