[PATCH v4 2/3] ethdev: avoid panicking in absence of ethdev shared data

[David Marchand <david.marchand@redhat.com>]

This is a preparation step before freeing the ethdev shared data
memzone.

Previously, because the primary process never freed the memzone, a
secondary process could assume this memzone was present.
But in the next commit, this will change.

Make eth_dev_shared_data_prepare() report whether the memzone is
available so that upper level API can react accordingly.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 lib/ethdev/ethdev_driver.c  | 23 ++++++++++++++-----
 lib/ethdev/ethdev_private.c | 10 +++++---
 lib/ethdev/ethdev_private.h |  2 +-
 lib/ethdev/ethdev_trace.h   |  6 +++--
 lib/ethdev/rte_ethdev.c     | 46 +++++++++++++++++++++++++------------
 5 files changed, 60 insertions(+), 27 deletions(-)

diff --git a/lib/ethdev/ethdev_driver.c b/lib/ethdev/ethdev_driver.c
index c92cd4b947..b339e325a0 100644
--- a/lib/ethdev/ethdev_driver.c
+++ b/lib/ethdev/ethdev_driver.c
@@ -92,7 +92,8 @@ rte_eth_dev_allocate(const char *name)
 	/* Synchronize port creation between primary and secondary processes. */
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
+	if (eth_dev_shared_data_prepare() == NULL)
+		goto unlock;
 
 	if (eth_dev_allocated(name) != NULL) {
 		RTE_ETHDEV_LOG(ERR,
@@ -128,9 +129,10 @@ rte_eth_dev_allocated(const char *name)
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
-
-	ethdev = eth_dev_allocated(name);
+	if (eth_dev_shared_data_prepare() != NULL)
+		ethdev = eth_dev_allocated(name);
+	else
+		ethdev = NULL;
 
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
 
@@ -151,7 +153,8 @@ rte_eth_dev_attach_secondary(const char *name)
 	/* Synchronize port attachment to primary port creation and release. */
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
+	if (eth_dev_shared_data_prepare() == NULL)
+		goto unlock;
 
 	for (i = 0; i < RTE_MAX_ETHPORTS; i++) {
 		if (strcmp(eth_dev_shared_data->data[i].name, name) == 0)
@@ -166,6 +169,7 @@ rte_eth_dev_attach_secondary(const char *name)
 		RTE_ASSERT(eth_dev->data->port_id == i);
 	}
 
+unlock:
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
 	return eth_dev;
 }
@@ -219,12 +223,19 @@ rte_eth_dev_probing_finish(struct rte_eth_dev *dev)
 int
 rte_eth_dev_release_port(struct rte_eth_dev *eth_dev)
 {
+	int ret;
+
 	if (eth_dev == NULL)
 		return -EINVAL;
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
-	eth_dev_shared_data_prepare();
+	if (eth_dev_shared_data_prepare() == NULL)
+		ret = -EINVAL;
+	else
+		ret = 0;
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
+	if (ret != 0)
+		return ret;
 
 	if (eth_dev->state != RTE_ETH_DEV_UNUSED)
 		rte_eth_dev_callback_process(eth_dev,
diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
index 6756625729..911de1e595 100644
--- a/lib/ethdev/ethdev_private.c
+++ b/lib/ethdev/ethdev_private.c
@@ -318,7 +318,7 @@ rte_eth_call_tx_callbacks(uint16_t port_id, uint16_t queue_id,
 	return nb_pkts;
 }
 
-void
+void *
 eth_dev_shared_data_prepare(void)
 {
 	const unsigned int flags = 0;
@@ -332,8 +332,10 @@ eth_dev_shared_data_prepare(void)
 					rte_socket_id(), flags);
 		} else
 			mz = rte_memzone_lookup(MZ_RTE_ETH_DEV_DATA);
-		if (mz == NULL)
-			rte_panic("Cannot allocate ethdev shared data\n");
+		if (mz == NULL) {
+			RTE_ETHDEV_LOG(ERR, "Cannot allocate ethdev shared data\n");
+			goto out;
+		}
 
 		eth_dev_shared_data = mz->addr;
 		if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
@@ -343,6 +345,8 @@ eth_dev_shared_data_prepare(void)
 			       sizeof(eth_dev_shared_data->data));
 		}
 	}
+out:
+	return eth_dev_shared_data;
 }
 
 void
diff --git a/lib/ethdev/ethdev_private.h b/lib/ethdev/ethdev_private.h
index f7706e6a95..1572da7b48 100644
--- a/lib/ethdev/ethdev_private.h
+++ b/lib/ethdev/ethdev_private.h
@@ -67,7 +67,7 @@ void eth_dev_fp_ops_setup(struct rte_eth_fp_ops *fpo,
 		const struct rte_eth_dev *dev);
 
 
-void eth_dev_shared_data_prepare(void)
+void *eth_dev_shared_data_prepare(void)
 	__rte_exclusive_locks_required(rte_mcfg_ethdev_get_lock());
 
 void eth_dev_rxq_release(struct rte_eth_dev *dev, uint16_t qid);
diff --git a/lib/ethdev/ethdev_trace.h b/lib/ethdev/ethdev_trace.h
index 423e71236e..e367d29c3a 100644
--- a/lib/ethdev/ethdev_trace.h
+++ b/lib/ethdev/ethdev_trace.h
@@ -112,8 +112,9 @@ RTE_TRACE_POINT(
 
 RTE_TRACE_POINT(
 	rte_ethdev_trace_owner_new,
-	RTE_TRACE_POINT_ARGS(uint64_t owner_id),
+	RTE_TRACE_POINT_ARGS(uint64_t owner_id, int ret),
 	rte_trace_point_emit_u64(owner_id);
+	rte_trace_point_emit_int(ret);
 )
 
 RTE_TRACE_POINT(
@@ -377,10 +378,11 @@ RTE_TRACE_POINT(
 RTE_TRACE_POINT(
 	rte_ethdev_trace_owner_get,
 	RTE_TRACE_POINT_ARGS(uint16_t port_id,
-		const struct rte_eth_dev_owner *owner),
+		const struct rte_eth_dev_owner *owner, int ret),
 	rte_trace_point_emit_u16(port_id);
 	rte_trace_point_emit_u64(owner->id);
 	rte_trace_point_emit_string(owner->name);
+	rte_trace_point_emit_int(ret);
 )
 
 RTE_TRACE_POINT(
diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index e0d22c27c6..5c9495ecfe 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -388,7 +388,7 @@ rte_eth_find_next_sibling(uint16_t port_id, uint16_t ref_port_id)
 static bool
 eth_dev_is_allocated(const struct rte_eth_dev *ethdev)
 {
-	return ethdev->data->name[0] != '\0';
+	return ethdev->data != NULL && ethdev->data->name[0] != '\0';
 }
 
 int
@@ -433,6 +433,8 @@ rte_eth_find_next_owned_by(uint16_t port_id, const uint64_t owner_id)
 int
 rte_eth_dev_owner_new(uint64_t *owner_id)
 {
+	int ret;
+
 	if (owner_id == NULL) {
 		RTE_ETHDEV_LOG(ERR, "Cannot get new owner ID to NULL\n");
 		return -EINVAL;
@@ -440,14 +442,18 @@ rte_eth_dev_owner_new(uint64_t *owner_id)
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
-	*owner_id = eth_dev_shared_data->next_owner_id++;
+	if (eth_dev_shared_data_prepare() != NULL) {
+		*owner_id = eth_dev_shared_data->next_owner_id++;
+		ret = 0;
+	} else {
+		ret = -ENOMEM;
+	}
 
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
 
-	rte_ethdev_trace_owner_new(*owner_id);
+	rte_ethdev_trace_owner_new(*owner_id, ret);
 
-	return 0;
+	return ret;
 }
 
 static int
@@ -506,8 +512,10 @@ rte_eth_dev_owner_set(const uint16_t port_id,
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
-	ret = eth_dev_owner_set(port_id, RTE_ETH_DEV_NO_OWNER, owner);
+	if (eth_dev_shared_data_prepare() != NULL)
+		ret = eth_dev_owner_set(port_id, RTE_ETH_DEV_NO_OWNER, owner);
+	else
+		ret = -ENOMEM;
 
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
 
@@ -525,8 +533,10 @@ rte_eth_dev_owner_unset(const uint16_t port_id, const uint64_t owner_id)
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
-	ret = eth_dev_owner_set(port_id, owner_id, &new_owner);
+	if (eth_dev_shared_data_prepare() != NULL)
+		ret = eth_dev_owner_set(port_id, owner_id, &new_owner);
+	else
+		ret = -ENOMEM;
 
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
 
@@ -543,8 +553,9 @@ rte_eth_dev_owner_delete(const uint64_t owner_id)
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
-	if (eth_is_valid_owner_id(owner_id)) {
+	if (eth_dev_shared_data_prepare() == NULL) {
+		ret = -ENOMEM;
+	} else if (eth_is_valid_owner_id(owner_id)) {
 		for (port_id = 0; port_id < RTE_MAX_ETHPORTS; port_id++) {
 			struct rte_eth_dev_data *data =
 				rte_eth_devices[port_id].data;
@@ -573,6 +584,7 @@ int
 rte_eth_dev_owner_get(const uint16_t port_id, struct rte_eth_dev_owner *owner)
 {
 	struct rte_eth_dev *ethdev;
+	int ret;
 
 	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
 	ethdev = &rte_eth_devices[port_id];
@@ -591,14 +603,18 @@ rte_eth_dev_owner_get(const uint16_t port_id, struct rte_eth_dev_owner *owner)
 
 	rte_spinlock_lock(rte_mcfg_ethdev_get_lock());
 
-	eth_dev_shared_data_prepare();
-	rte_memcpy(owner, &ethdev->data->owner, sizeof(*owner));
+	if (eth_dev_shared_data_prepare() != NULL) {
+		rte_memcpy(owner, &ethdev->data->owner, sizeof(*owner));
+		ret = 0;
+	} else {
+		ret = -ENOMEM;
+	}
 
 	rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
 
-	rte_ethdev_trace_owner_get(port_id, owner);
+	rte_ethdev_trace_owner_get(port_id, owner, ret);
 
-	return 0;
+	return ret;
 }
 
 int
-- 
2.41.0