Hi, Thomas

*The commit log：*
In secondary process, rte_eth_dev_close() doesn't clear eth_dev->data.
If calling rte_dev_remove() after rte_eth_dev_close(), in 
rte_eth_dev_pci_generic_remove()
function, the released eth device still can be found by its name in 
shared memory.
As a result, the eth device will be released repeatedly. The state of 
the eth device
is modified to RTE_ETH_DEV_UNUSED after rte_eth_dev_close(). So this 
state can
be used to avoid this problem.

Is that will be more clear?

/*
  * A released eth device can be found by its name in shared memory.
  * If the state of the eth device is RTE_ETH_DEV_UNUSED, which means
  * the eth device has been released.
  */

Is it ok to use the above description as a comment in the code?

Hope for your reply.  Thanks.


在 2021/10/12 23:33, Thomas Monjalon 写道:

12/10/2021 13:39, Huisong Li:

quoted

The rte_eth_dev_pci_generic_remove() will be called to detach an Ethernet
device when App calls rte_dev_remove() to detach a pci device. In addition,
the rte_eth_dev_close() can also detach an Ethernet device.
In secondary process, if App first calls rte_eth_dev_close() and then calls
rte_dev_remove(), because rte_eth_dev_close() doesn't clear "eth_dev->data"

It would be clearer if you start this sentence with:
"In secondary process, rte_eth_dev_close() doesn't clear eth_dev->data."
Then you can explain that if calling rte_dev_remove() after rte_eth_dev_close(),
etc...

quoted

, the address of the released Ethernet device can still be found by device
name. As a result, the Ethernet device will be released repeatedly in this
case. The state of the Ethernet device is equal to RTE_ETH_DEV_UNUSED after
calling rte_eth_dev_close(). Use this state to avoid this problem.

Signed-off-by: Huisong Li<lihuisong@huawei.com>
---
+	/*
+	 * In secondary process, if applications first call rte_eth_dev_close()
+	 * and then call this interface, because rte_eth_dev_close() doesn't
+	 * clear eth_dev->data, the address of the released Ethernet device can
+	 * still be found by device name. As a result, the Ethernet device will
+	 * be released repeatedly in this case.
+	 * The state of the Ethernet device is equal to RTE_ETH_DEV_UNUSED after
+	 * calling rte_eth_dev_close(). Use this state to avoid this problem.

This is a comment for the commit log.
Inside the code, we should be more to the point.
I suggest this comment:
/* A released port can be found by its name in shared memory. */

quoted

+	 */
+	if (rte_eal_process_type() != RTE_PROC_PRIMARY &&

Better to directly compare with RTE_PROC_SECONDARY

quoted

+	    eth_dev->state == RTE_ETH_DEV_UNUSED) {
+		RTE_ETHDEV_LOG(INFO, "The ethdev port has been released.");

Not sure we need any log here.

quoted

+		return 0;
+	}

.