ethdev: refresh shared memory reference in secondary process
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Commit Message
In the process of releasing ethdev port in the primary process,
secondary processes are asked to stop referencing such a port.
Doing so, those processes can't predict whether the primary process
will later invalidate/free the shared memory. So they may live with a
reference to an old shared memory memzone and location in memory.
Refresh the shared memory pointer in secondary process when requesting
access to the shared memory: this is the best moment ethdev can check
it because the primary process will (re-)create a shared memory only if
no secondary process is referencing a ethdev port.
Bugzilla ID: 1303
Fixes: 36c46e738120 ("ethdev: cleanup shared data with the last port")
Signed-off-by: David Marchand <david.marchand@redhat.com>
---
lib/ethdev/ethdev_private.c | 46 ++++++++++++++++++++++++-------------
1 file changed, 30 insertions(+), 16 deletions(-)
Comments
On 10/20/2023 1:06 PM, David Marchand wrote:
> In the process of releasing ethdev port in the primary process,
> secondary processes are asked to stop referencing such a port.
> Doing so, those processes can't predict whether the primary process
> will later invalidate/free the shared memory. So they may live with a
> reference to an old shared memory memzone and location in memory.
>
> Refresh the shared memory pointer in secondary process when requesting
> access to the shared memory: this is the best moment ethdev can check
> it because the primary process will (re-)create a shared memory only if
> no secondary process is referencing a ethdev port.
>
> Bugzilla ID: 1303
> Fixes: 36c46e738120 ("ethdev: cleanup shared data with the last port")
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
>
Reviewed-by: Ferruh Yigit <ferruh.yigit@amd.com>
Applied to dpdk-next-net/main, thanks.
@@ -324,17 +324,18 @@ rte_eth_call_tx_callbacks(uint16_t port_id, uint16_t queue_id,
void *
eth_dev_shared_data_prepare(void)
{
- const unsigned int flags = 0;
const struct rte_memzone *mz;
- if (eth_dev_shared_mz == NULL) {
- if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
- /* Allocate port data and ownership shared memory. */
- mz = rte_memzone_reserve(MZ_RTE_ETH_DEV_DATA,
- sizeof(*eth_dev_shared_data),
- rte_socket_id(), flags);
- } else
- mz = rte_memzone_lookup(MZ_RTE_ETH_DEV_DATA);
+ if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+ const unsigned int flags = 0;
+
+ if (eth_dev_shared_mz != NULL)
+ goto out;
+
+ /* Allocate port data and ownership shared memory. */
+ mz = rte_memzone_reserve(MZ_RTE_ETH_DEV_DATA,
+ sizeof(*eth_dev_shared_data),
+ rte_socket_id(), flags);
if (mz == NULL) {
RTE_ETHDEV_LOG(ERR, "Cannot allocate ethdev shared data\n");
goto out;
@@ -342,14 +343,27 @@ eth_dev_shared_data_prepare(void)
eth_dev_shared_mz = mz;
eth_dev_shared_data = mz->addr;
- if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
- eth_dev_shared_data->allocated_owners = 0;
- eth_dev_shared_data->next_owner_id =
- RTE_ETH_DEV_NO_OWNER + 1;
- eth_dev_shared_data->allocated_ports = 0;
- memset(eth_dev_shared_data->data, 0,
- sizeof(eth_dev_shared_data->data));
+ eth_dev_shared_data->allocated_owners = 0;
+ eth_dev_shared_data->next_owner_id =
+ RTE_ETH_DEV_NO_OWNER + 1;
+ eth_dev_shared_data->allocated_ports = 0;
+ memset(eth_dev_shared_data->data, 0,
+ sizeof(eth_dev_shared_data->data));
+ } else {
+ mz = rte_memzone_lookup(MZ_RTE_ETH_DEV_DATA);
+ if (mz == NULL) {
+ /* Clean remaining any traces of a previous shared mem */
+ eth_dev_shared_mz = NULL;
+ eth_dev_shared_data = NULL;
+ RTE_ETHDEV_LOG(ERR, "Cannot lookup ethdev shared data\n");
+ goto out;
}
+ if (mz == eth_dev_shared_mz && mz->addr == eth_dev_shared_data)
+ goto out;
+
+ /* Shared mem changed in primary process, refresh pointers */
+ eth_dev_shared_mz = mz;
+ eth_dev_shared_data = mz->addr;
}
out:
return eth_dev_shared_data;