[dpdk-dev] [PATCH v2] dev: fix attach rollback of a device that was already attached

[Darek Stojaczyk]

When primary process receives an IPC attach request
of a device that's already locally-attached, it
doesn't setup its variables properly and is prone to
segfaulting on a subsequent rollback.

`ret = local_dev_probe(req->devargs, &dev)`

The above function will set `dev` pointer to the
proper device *unless* it returns with error. One of
those errors is -EEXIST, which the hotplug function
explicitly ignores. For -EEXIST, it proceeds with
attaching the device and expects the dev pointer to
be valid.

This patch makes `local_dev_probe` set the dev pointer
even if it returns -EEXIST.

Fixes: ac9e4a17370f ("eal: support attach/detach shared device from secondary")
Cc: qi.z.zhang at intel.com

Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk at intel.com>
---
Changes since v1:
 * attempt to detach the device in primary process (Qi)

 lib/librte_eal/common/eal_common_dev.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
index 1fdc9ab17..a08dc085f 100644
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -168,16 +168,14 @@ local_dev_probe(const char *devargs, struct rte_device **new_dev)
 	}
 
 	ret = dev->bus->plug(dev);
-	if (ret) {
-		if (rte_dev_is_probed(dev)) /* if already succeeded earlier */
-			return ret; /* no rollback */
+	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);
 		goto err_devarg;
 	}
 
 	*new_dev = dev;
-	return 0;
+	return ret;
 
 err_devarg:
 	if (rte_devargs_remove(da) != 0) {
-- 
2.17.1