Merge branch 'sfp-eeprom'

Ivan Bornyakov says:

====================
net: fix EEPROM read of absent SFP module

The patchset is to improve EEPROM read requests when SFP module is
absent.

ChangeLog:
v1:
https://lore.kernel.org/netdev/20230405153900.747-1-i.bornyakov@metrotek.ru/
v2:
  * reword commit message of "net: sfp: initialize sfp->i2c_block_size
    at sfp allocation"
  * add second patch to eliminate excessive I2C transfers in
    sfp_module_eeprom() and sfp_module_eeprom_by_page()
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Author: davem330

drivers/net/phy/sfp.c

@@ -210,6 +210,12 @@ static const enum gpiod_flags gpio_flags[] = {
 #define SFP_PHY_ADDR		22
 #define SFP_PHY_ADDR_ROLLBALL	17
 
+/* SFP_EEPROM_BLOCK_SIZE is the size of data chunk to read the EEPROM
+ * at a time. Some SFP modules and also some Linux I2C drivers do not like
+ * reads longer than 16 bytes.
+ */
+#define SFP_EEPROM_BLOCK_SIZE	16
+
 struct sff_data {
 	unsigned int gpios;
 	bool (*module_supported)(const struct sfp_eeprom_id *id);
@@ -1929,11 +1935,7 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
 	u8 check;
 	int ret;
 
-	/* Some SFP modules and also some Linux I2C drivers do not like reads
-	 * longer than 16 bytes, so read the EEPROM in chunks of 16 bytes at
-	 * a time.
-	 */
-	sfp->i2c_block_size = 16;
+	sfp->i2c_block_size = SFP_EEPROM_BLOCK_SIZE;
 
 	ret = sfp_read(sfp, false, 0, &id.base, sizeof(id.base));
 	if (ret < 0) {
@@ -2485,6 +2487,9 @@ static int sfp_module_eeprom(struct sfp *sfp, struct ethtool_eeprom *ee,
 	unsigned int first, last, len;
 	int ret;
 
+	if (!(sfp->state & SFP_F_PRESENT))
+		return -ENODEV;
+
 	if (ee->len == 0)
 		return -EINVAL;
 
@@ -2517,6 +2522,9 @@ static int sfp_module_eeprom_by_page(struct sfp *sfp,
 				     const struct ethtool_module_eeprom *page,
 				     struct netlink_ext_ack *extack)
 {
+	if (!(sfp->state & SFP_F_PRESENT))
+		return -ENODEV;
+
 	if (page->bank) {
 		NL_SET_ERR_MSG(extack, "Banks not supported");
 		return -EOPNOTSUPP;
@@ -2621,6 +2629,7 @@ static struct sfp *sfp_alloc(struct device *dev)
 		return ERR_PTR(-ENOMEM);
 
 	sfp->dev = dev;
+	sfp->i2c_block_size = SFP_EEPROM_BLOCK_SIZE;
 
 	mutex_init(&sfp->sm_mutex);
 	mutex_init(&sfp->st_mutex);