[PATCH net-next v2 1/7] net: stmmac: provide plat_dat->dma_cfg in stmmac_plat_dat_alloc()

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

plat_dat->dma_cfg is unconditionally required for the operation of the
driver, so it would make sense to allocate it along with the plat_dat.

On Arm64, sizeof(*plat_dat) has recently shrunk from 880 to 816 bytes
and sizeof(*plat_dat->dma_cfg) has shrunk from 32 to 20 bytes.

Given that dma_cfg is required, and it is now less than a cache line,
It doesn't make sense to allocate this separateny, so place it at the
end of struct plat_stmmacenet_data, and set plat_dat->dma_cfg to point
at that to avoid mass changes.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c     | 5 -----
 drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c  | 4 ----
 drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c | 4 ----
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c     | 2 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c      | 5 -----
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 8 +-------
 include/linux/stmmac.h                                | 1 +
 7 files changed, 4 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index fc13bfb47783..0b32560cd059 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
@@ -1251,11 +1251,6 @@ static int intel_eth_pci_probe(struct pci_dev *pdev,
 	if (!plat->mdio_bus_data)
 		return -ENOMEM;
 
-	plat->dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*plat->dma_cfg),
-				     GFP_KERNEL);
-	if (!plat->dma_cfg)
-		return -ENOMEM;
-
 	plat->safety_feat_cfg = devm_kzalloc(&pdev->dev,
 					     sizeof(*plat->safety_feat_cfg),
 					     GFP_KERNEL);
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
index ada6c6ef1f5c..51b1562f84d1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c
@@ -513,10 +513,6 @@ static int loongson_dwmac_probe(struct pci_dev *pdev, const struct pci_device_id
 	if (!plat->mdio_bus_data)
 		return -ENOMEM;
 
-	plat->dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*plat->dma_cfg), GFP_KERNEL);
-	if (!plat->dma_cfg)
-		return -ENOMEM;
-
 	ld = devm_kzalloc(&pdev->dev, sizeof(*ld), GFP_KERNEL);
 	if (!ld)
 		return -ENOMEM;
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c
index 8b45b9cf7202..d245546b90db 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-motorcomm.c
@@ -218,10 +218,6 @@ motorcomm_default_plat_data(struct pci_dev *pdev)
 	if (!plat->mdio_bus_data)
 		return NULL;
 
-	plat->dma_cfg = devm_kzalloc(dev, sizeof(*plat->dma_cfg), GFP_KERNEL);
-	if (!plat->dma_cfg)
-		return NULL;
-
 	plat->axi = devm_kzalloc(dev, sizeof(*plat->axi), GFP_KERNEL);
 	if (!plat->axi)
 		return NULL;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index f0160ff54a59..87f43811faa0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -7730,6 +7730,8 @@ struct plat_stmmacenet_data *stmmac_plat_dat_alloc(struct device *dev)
 	if (!plat_dat)
 		return NULL;
 
+	plat_dat->dma_cfg = &plat_dat->__dma_cfg;
+
 	/* Set the defaults:
 	 * - phy autodetection
 	 * - determine GMII_Address CR field from CSR clock
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
index 270ad066ced3..836fed7d60ab 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
@@ -134,11 +134,6 @@ static int stmmac_pci_probe(struct pci_dev *pdev,
 	if (!plat->mdio_bus_data)
 		return -ENOMEM;
 
-	plat->dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*plat->dma_cfg),
-				     GFP_KERNEL);
-	if (!plat->dma_cfg)
-		return -ENOMEM;
-
 	plat->safety_feat_cfg = devm_kzalloc(&pdev->dev,
 					     sizeof(*plat->safety_feat_cfg),
 					     GFP_KERNEL);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index c34998486293..1aed48fe0db6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -548,13 +548,7 @@ stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac)
 				     &plat->multicast_filter_bins);
 	}
 
-	dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*dma_cfg),
-			       GFP_KERNEL);
-	if (!dma_cfg) {
-		ret = ERR_PTR(-ENOMEM);
-		goto error_put_mdio;
-	}
-	plat->dma_cfg = dma_cfg;
+	dma_cfg = plat->dma_cfg;
 
 	of_property_read_u32(np, "snps,pbl", &dma_cfg->pbl);
 	if (!dma_cfg->pbl)
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 965ada809fdf..919196713c05 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -306,5 +306,6 @@ struct plat_stmmacenet_data {
 	int msi_tx_base_vec;
 	const struct dwmac4_addrs *dwmac4_addrs;
 	unsigned int flags;
+	struct stmmac_dma_cfg __dma_cfg;
 };
 #endif
-- 
2.47.3