From: Jonas Jelonek Date: Thu, 28 May 2026 20:52:40 +0000 (+0000) Subject: net: sfp: initialize i2c_block_size at adapter configure time X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=56d0885514491e5ed8f7593400879ab77c52504c;p=thirdparty%2Flinux.git net: sfp: initialize i2c_block_size at adapter configure time sfp->i2c_block_size is only assigned in sfp_sm_mod_probe(), which runs from the state machine timer after SFP_F_PRESENT has been set. Between those two points, sfp_module_eeprom() (the ethtool -m callback) gates only on SFP_F_PRESENT and can be entered with i2c_block_size still at its kzalloc'd value of 0. On a pure-I2C adapter, sfp_i2c_read() then issues an i2c_transfer() with msgs[1].len = 0 inside a loop that subtracts this_len from len each iteration; on adapters that succeed a zero-length read the loop never advances, spinning while holding rtnl_lock. This was previously addressed by initializing i2c_block_size in sfp_alloc() (commit 813c2dd78618), but the initialization was dropped when i2c_block_size was split from i2c_max_block_size. Initialize sfp->i2c_block_size from sfp->i2c_max_block_size in sfp_i2c_configure(), so the field is valid as soon as the adapter is known. sfp_sm_mod_probe() still reassigns it on each module insertion to recover from a per-module clamp to 1 (sfp_id_needs_byte_io). Fixes: 7662abf4db94 ("net: phy: sfp: Add support for SMBus module access") Cc: stable@vger.kernel.org Signed-off-by: Jonas Jelonek Link: https://patch.msgid.link/20260528205242.971410-2-jelonek.jonas@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c index bd970f753beb..b94b9c433a21 100644 --- a/drivers/net/phy/sfp.c +++ b/drivers/net/phy/sfp.c @@ -822,6 +822,7 @@ static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c) return -EINVAL; } + sfp->i2c_block_size = sfp->i2c_max_block_size; return 0; }