ethernet: sun: niu: fix missing checks of niu_pci_eeprom_read()

niu_pci_eeprom_read() may fail, so add checks to its return value and
propagate the error up the callstack.

An examination of the callstack up to niu_pci_eeprom_read shows that:

niu_pci_eeprom_read() // returns int
    niu_pci_vpd_scan_props() // returns int
        niu_pci_vpd_fetch() // returns *void*
            niu_get_invariants() // returns int

since niu_pci_vpd_fetch() returns void which breaks the bubbling up,
change its return type to int so that error is propagated upwards.
Signed-off-by: Du Cheng <ducheng2@gmail.com>
Cc: Shannon Nelson <shannon.lee.nelson@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210503115736.2104747-24-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/sun/niu.c

@@ -8097,6 +8097,8 @@ static int niu_pci_vpd_scan_props(struct niu *np, u32 start, u32 end)
 		start += 3;
 
 		prop_len = niu_pci_eeprom_read(np, start + 4);
+		if (prop_len < 0)
+			return prop_len;
 		err = niu_pci_vpd_get_propname(np, start + 5, namebuf, 64);
 		if (err < 0)
 			return err;
@@ -8141,8 +8143,12 @@ static int niu_pci_vpd_scan_props(struct niu *np, u32 start, u32 end)
 			netif_printk(np, probe, KERN_DEBUG, np->dev,
 				     "VPD_SCAN: Reading in property [%s] len[%d]\n",
 				     namebuf, prop_len);
-			for (i = 0; i < prop_len; i++)
-				*prop_buf++ = niu_pci_eeprom_read(np, off + i);
+			for (i = 0; i < prop_len; i++) {
+				err =  niu_pci_eeprom_read(np, off + i);
+				if (err < 0)
+					return err;
+				*prop_buf++ = err;
+			}
 		}
 
 		start += len;
@@ -8152,14 +8158,14 @@ static int niu_pci_vpd_scan_props(struct niu *np, u32 start, u32 end)
 }
 
 /* ESPC_PIO_EN_ENABLE must be set */
-static void niu_pci_vpd_fetch(struct niu *np, u32 start)
+static int niu_pci_vpd_fetch(struct niu *np, u32 start)
 {
 	u32 offset;
 	int err;
 
 	err = niu_pci_eeprom_read16_swp(np, start + 1);
 	if (err < 0)
-		return;
+		return err;
 
 	offset = err + 3;
 
@@ -8168,12 +8174,14 @@ static void niu_pci_vpd_fetch(struct niu *np, u32 start)
 		u32 end;
 
 		err = niu_pci_eeprom_read(np, here);
+		if (err < 0)
+			return err;
 		if (err != 0x90)
-			return;
+			return -EINVAL;
 
 		err = niu_pci_eeprom_read16_swp(np, here + 1);
 		if (err < 0)
-			return;
+			return err;
 
 		here = start + offset + 3;
 		end = start + offset + err;
@@ -8181,9 +8189,12 @@ static void niu_pci_vpd_fetch(struct niu *np, u32 start)
 		offset += err;
 
 		err = niu_pci_vpd_scan_props(np, here, end);
-		if (err < 0 || err == 1)
-			return;
+		if (err < 0)
+			return err;
+		if (err == 1)
+			return -EINVAL;
 	}
+	return 0;
 }
 
 /* ESPC_PIO_EN_ENABLE must be set */
@@ -9274,8 +9285,11 @@ static int niu_get_invariants(struct niu *np)
 		offset = niu_pci_vpd_offset(np);
 		netif_printk(np, probe, KERN_DEBUG, np->dev,
 			     "%s() VPD offset [%08x]\n", __func__, offset);
-		if (offset)
-			niu_pci_vpd_fetch(np, offset);
+		if (offset) {
+			err = niu_pci_vpd_fetch(np, offset);
+			if (err < 0)
+				return err;
+		}
 		nw64(ESPC_PIO_EN, 0);
 
 		if (np->flags & NIU_FLAGS_VPD_VALID) {