If probe fails in multi-process context, the device must removed
in other processes for consistency. This is a rollback mechanism.
However the rollback should not happen for devices which were
already probed before the current probe transaction.
When probing an already probed device, the driver may reject
with -EEXIST or update and succeed with code 0.
In order to distinguish successful new probe from re-probe,
in the function local_dev_probe(), the positive EEXIST code
is returned for the latter case.
The functions rte_dev_probe() and __handle_secondary_request()
can test for -EEXIST and +EEXIST, and skip rollback in such case.
Fixes: 244d5130719c ("eal: enable hotplug on multi-process")
Fixes: ac9e4a17370f ("eal: support attach/detach shared device from secondary")
Cc: qi.z.zh...@intel.com
Cc: sta...@dpdk.org
Signed-off-by: Thomas Monjalon <tho...@monjalon.net>
---
lib/librte_eal/common/eal_common_dev.c | 12 ++++++++++--
lib/librte_eal/common/eal_private.h | 2 +-
lib/librte_eal/common/hotplug_mp.c | 8 ++++++--
3 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/lib/librte_eal/common/eal_common_dev.c
b/lib/librte_eal/common/eal_common_dev.c
index deaaea9345..2c7b1ab071 100644
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -132,6 +132,7 @@ local_dev_probe(const char *devargs, struct rte_device
**new_dev)
{
struct rte_device *dev;
struct rte_devargs *da;
+ bool already_probed;
int ret;
*new_dev = NULL;
@@ -171,12 +172,15 @@ local_dev_probe(const char *devargs, struct rte_device
**new_dev)
* those devargs shouldn't be removed manually anymore.
*/
+ already_probed = rte_dev_is_probed(dev);
ret = dev->bus->plug(dev);
if (ret && !rte_dev_is_probed(dev)) { /* if hasn't ever succeeded */
RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
dev->name);
return ret;
}
+ if (ret == 0 && already_probed)
+ ret = EEXIST; /* hint to avoid any rollback */
*new_dev = dev;
return ret;
@@ -194,6 +198,7 @@ rte_dev_probe(const char *devargs)
{
struct eal_dev_mp_req req;
struct rte_device *dev;
+ bool already_probed;
int ret;
memset(&req, 0, sizeof(req));
@@ -221,8 +226,8 @@ rte_dev_probe(const char *devargs)
/* primary attach the new device itself. */
ret = local_dev_probe(devargs, &dev);
-
- if (ret != 0 && ret != -EEXIST) {
+ already_probed = (ret == -EEXIST || ret == EEXIST);
+ if (ret < 0 && !already_probed) {
RTE_LOG(ERR, EAL,
"Failed to attach device on primary process\n");
return ret;
@@ -250,6 +255,9 @@ rte_dev_probe(const char *devargs)
return 0;
rollback:
+ if (already_probed)
+ return ret; /* skip rollback */
+
req.t = EAL_DEV_REQ_TYPE_ATTACH_ROLLBACK;
/* primary send rollback request to secondary. */
diff --git a/lib/librte_eal/common/eal_private.h
b/lib/librte_eal/common/eal_private.h
index 798ede553b..a01d252930 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -304,7 +304,7 @@ rte_devargs_layers_parse(struct rte_devargs *devargs,
* @param new_dev
* new device be probed as output.
* @return
- * 0 on success, negative on error.
+ * >=0 on success (+EEXIST if already probed), negative on error.
*/
int local_dev_probe(const char *devargs, struct rte_device **new_dev);
diff --git a/lib/librte_eal/common/hotplug_mp.c
b/lib/librte_eal/common/hotplug_mp.c
index 69e9a16d6a..9f8ef28a3b 100644
--- a/lib/librte_eal/common/hotplug_mp.c
+++ b/lib/librte_eal/common/hotplug_mp.c
@@ -90,13 +90,15 @@ __handle_secondary_request(void *param)
struct rte_devargs da;
struct rte_device *dev;
struct rte_bus *bus;
+ bool already_probed = false;
int ret = 0;
tmp_req = *req;
if (req->t == EAL_DEV_REQ_TYPE_ATTACH) {
ret = local_dev_probe(req->devargs, &dev);
- if (ret != 0 && ret != -EEXIST) {
+ already_probed = (ret == -EEXIST || ret == EEXIST);
+ if (ret < 0 && !already_probed) {
RTE_LOG(ERR, EAL, "Failed to hotplug add device on
primary\n");
goto finish;
}
@@ -159,7 +161,7 @@ __handle_secondary_request(void *param)
goto finish;
rollback:
- if (req->t == EAL_DEV_REQ_TYPE_ATTACH) {
+ if (req->t == EAL_DEV_REQ_TYPE_ATTACH && !already_probed) {
tmp_req.t = EAL_DEV_REQ_TYPE_ATTACH_ROLLBACK;
eal_dev_hotplug_request_to_secondary(&tmp_req);
local_dev_remove(dev);
@@ -238,6 +240,8 @@ static void __handle_primary_request(void *param)
case EAL_DEV_REQ_TYPE_ATTACH:
case EAL_DEV_REQ_TYPE_DETACH_ROLLBACK:
ret = local_dev_probe(req->devargs, &dev);
+ if (ret > 0)
+ ret = 0; /* return only errors */
break;
case EAL_DEV_REQ_TYPE_DETACH:
case EAL_DEV_REQ_TYPE_ATTACH_ROLLBACK:
--
2.20.1
