From 04d36d7c373db7069554a6d21ece628e2cf6b21c Mon Sep 17 00:00:00 2001

From: Ido Schimmel <idosch@nvidia.com>

Date: Tue, 14 Sep 2021 14:27:36 +0300

Subject: [PATCH 03/35] netlink: eeprom: Fallback to IOCTL when a complete

 hex/raw dump is requested

The IOCTL backend provides a complete hex/raw dump of the module EEPROM

contents:

 # ethtool -m swp11 hex on | wc -l

 34

 # ethtool -m swp11 raw on | wc -c

 512

With the netlink backend, only the first 128 bytes from I2C address 0x50

are dumped:

 # ethtool -m swp11 hex on | wc -l

 10

 # ethtool -m swp11 raw on | wc -c

 128

The presence of optional / banked pages is unknown without parsing the

EEPROM contents which is unavailable when pretty printing is disabled

(i.e., configure --disable-pretty-dump). With the IOCTL backend, this

parsing happens inside the kernel.

Therefore, when a complete hex/raw dump is requested, fallback to the

IOCTL backend.

After the patch:

 # ethtool -m swp11 hex on | wc -l

 34

 # ethtool -m swp11 raw on | wc -c

 512

This avoids breaking users that are relying on current behavior.

If users want a hex/raw dump of optional/banked pages that are not

returned with the IOCTL backend, they will be required to request these

explicitly via the netlink backend. For example:

 # ethtool -m swp11 hex on page 0x2

This is desirable as that way there is no ambiguity regarding the

location of optional/banked pages in the dump.

Another way to implement the above would be to use the 'nlchk' callback

added in commit 67a9ef551661 ("ethtool: add nlchk for redirecting to

netlink"). However, it is called before the netlink instance is

initialized and before the command line parameters are parsed via

nl_parser().

Fixes: 25b64c66f58d ("ethtool: Add netlink handler for getmodule (-m)")

Signed-off-by: Ido Schimmel <idosch@nvidia.com>

---

 netlink/module-eeprom.c | 10 ++++++++++

 1 file changed, 10 insertions(+)

diff --git a/netlink/module-eeprom.c b/netlink/module-eeprom.c

index 38e7d2cd6cf3..e9a122df3259 100644

--- a/netlink/module-eeprom.c

+++ b/netlink/module-eeprom.c

@@ -365,6 +365,16 @@ int nl_getmodule(struct cmd_context *ctx)

 		return -EINVAL;

 	}

+	/* When complete hex/raw dump of the EEPROM is requested, fallback to

+	 * ioctl. Netlink can only request specific pages.

+	 */

+	if ((getmodule_cmd_params.dump_hex || getmodule_cmd_params.dump_raw) &&

+	    !getmodule_cmd_params.page && !getmodule_cmd_params.bank &&

+	    !getmodule_cmd_params.i2c_address) {

+		nlctx->ioctl_fallback = true;

+		return -EOPNOTSUPP;

+	}

+

 	request.i2c_address = ETH_I2C_ADDRESS_LOW;

 	request.length = 128;

 	ret = page_fetch(nlctx, &request);

-- 

2.35.1