On 7/19/21 9:58 AM, Xueming(Steven) Li wrote:

quoted

-----Original Message-----
From: Andrew Rybchenko <redacted>
Sent: Tuesday, July 13, 2021 12:18 AM
To: Ajit Khaparde <ajit.khaparde@broadcom.com>; Somnath Kotur <redacted>; John Daley
[off-list ref]; Hyong Youb Kim [off-list ref]; Beilei Xing [off-list ref]; Qiming Yang
[off-list ref]; Qi Zhang [off-list ref]; Haiyue Wang [off-list ref]; Matan Azrad
[off-list ref]; Shahaf Shuler [off-list ref]; Slava Ovsiienko [off-list ref]; NBU-Contact-Thomas
Monjalon [off-list ref]; Ferruh Yigit [off-list ref]; Xueming(Steven) Li [off-list ref]
Cc: dev@dpdk.org; Viacheslav Galaktionov <redacted>; stable@dpdk.org
Subject: [PATCH] ethdev: fix representor port ID search by name

From: Viacheslav Galaktionov <redacted>

Fix representor port ID search by name if the representor itself does not provide representors info. Getting a list of representors from
a representor does not make sense. Instead, a parent device should be used.

To this end, extend the rte_eth_dev_data structure to include the port ID of the parent device for representors.

Fixes: df7547a6a2cc ("ethdev: add helper function to get representor ID")
Cc: stable@dpdk.org

Signed-off-by: Viacheslav Galaktionov <redacted>
Signed-off-by: Andrew Rybchenko <redacted>
---
The new field is added into the hole in rte_eth_dev_data structure.
The patch does not change ABI, but extra care is required since ABI check is disabled for the structure because of the libabigail bug [1].

Potentially it is bad for out-of-tree drivers which implement representors but do not fill in a new parert_port_id field in
rte_eth_dev_data structure. Do we care?

May be the patch should add lines to release notes, but I'd like to get initial feedback first.

mlx5 changes should be reviwed by maintainers very carefully, since we are not sure if we patch it correctly.

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=28060

[snip]

quoted

--- a/lib/ethdev/ethdev_driver.h
+++ b/lib/ethdev/ethdev_driver.h

@@ -1248,8 +1248,8 @@ struct rte_eth_devargs {
   * For backward compatibility, if no representor info, direct
   * map legacy VF (no controller and pf).
   *
- * @param ethdev
- *  Handle of ethdev port.
+ * @param parent_port_id
+ *  Port ID of the backing device.
   * @param type
   *  Representor type.
   * @param controller

@@ -1266,7 +1266,7 @@ struct rte_eth_devargs {
   */
  __rte_internal
  int
-rte_eth_representor_id_get(const struct rte_eth_dev *ethdev,
+rte_eth_representor_id_get(uint16_t parent_port_id,

It make more sense to get representor info from parent port. Representor is a member of switch domain, PMD owns
the information of  the representor owner port and info of representors. This change looks better, but not sure
whether it valuable to introduce a new member to the EAL data structure.

IMHO, it is simply incorrect to return representors info on a
representor itself. Representor info is an information which
representors may be populated using the device.

If above statement is correct, we need a way to get parent device
by representor to do name to representor ID mapping. I see two
options to do it:
  A. Dedicated field in rte_eth_dev_data as the patch does.
  B. Dedicated ethdev op (since representor knows parent port ID anyway).
We have chosen (A) because of simplicity.