[PATCH net-next v2 0/9] ibmvnic: Reuse ltb, rx, tx pools

[PATCH net-next v2 0/9] ibmvnic: Reuse ltb, rx, tx pools

[Sukadev Bhattiprolu]

It can take a long time to free and reallocate rx and tx pools and long
term buffer (LTB) during each reset of the VNIC. This is specially true
when the partition (LPAR) is heavily loaded and going through a Logical
Partition Migration (LPM). The long drawn reset causes the LPAR to lose
connectivity for extended periods of time and results in "RMC connection"
errors and the LPM failing.

What is worse is that during the LPM we could get a failover because
of the lost connectivity. At that point, the vnic driver releases
even the resources it has already allocated and starts over.

As long as the resources we have already allocated are valid/applicable,
we might as well hold on to them while trying to allocate the remaining
resources. This patch set attempts to reuse the resources previously
allocated as long as they are valid. It seems to vastly improve the
time taken for the vnic reset. We have also not seen any RMC connection
issues during our testing with this patch set.

If the backing devices for a vnic adapter are not "matched" (see "pool
parameters" in patches 8 and 9) it is possible that we will still free
all the resources and allocate them. If that becomes a common problem,
we have to address it separately.

Thanks to input and extensive testing from Brian King, Cris Forno,
Dany Madden, Rick Lindsley.

Changelog[v2]
	[Jakub Kicinski] Fix kdoc issues

Sukadev Bhattiprolu (9):
  ibmvnic: consolidate related code in replenish_rx_pool()
  ibmvnic: Fix up some comments and messages
  ibmvnic: Use/rename local vars in init_rx_pools
  ibmvnic: Use/rename local vars in init_tx_pools
  ibmvnic: init_tx_pools move loop-invariant code out
  ibmvnic: use bitmap for LTB map_ids
  ibmvnic: Reuse LTB when possible
  ibmvnic: Reuse rx pools when possible
  ibmvnic: Reuse tx pools when possible

 drivers/net/ethernet/ibm/ibmvnic.c | 640 +++++++++++++++++++----------
 drivers/net/ethernet/ibm/ibmvnic.h |  10 +-
 2 files changed, 427 insertions(+), 223 deletions(-)

-- 
2.26.2

[PATCH net-next v2 1/9] ibmvnic: Consolidate code in replenish_rx_pool()

[Sukadev Bhattiprolu]

For better readability, consolidate related code in replenish_rx_pool()
and add some comments.

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index a775c69e4fd7..e8b1231be485 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -371,6 +371,8 @@ static void replenish_rx_pool(struct ibmvnic_adapter *adapter,
 		}
 
 		index = pool->free_map[pool->next_free];
+		pool->free_map[pool->next_free] = IBMVNIC_INVALID_MAP;
+		pool->next_free = (pool->next_free + 1) % pool->size;
 
 		if (pool->rx_buff[index].skb)
 			dev_err(dev, "Inconsistent free_map!\n");
@@ -380,14 +382,15 @@ static void replenish_rx_pool(struct ibmvnic_adapter *adapter,
 		dst = pool->long_term_buff.buff + offset;
 		memset(dst, 0, pool->buff_size);
 		dma_addr = pool->long_term_buff.addr + offset;
-		pool->rx_buff[index].data = dst;
 
-		pool->free_map[pool->next_free] = IBMVNIC_INVALID_MAP;
+		/* add the skb to an rx_buff in the pool */
+		pool->rx_buff[index].data = dst;
 		pool->rx_buff[index].dma = dma_addr;
 		pool->rx_buff[index].skb = skb;
 		pool->rx_buff[index].pool_index = pool->index;
 		pool->rx_buff[index].size = pool->buff_size;
 
+		/* queue the rx_buff for the next send_subcrq_indirect */
 		sub_crq = &ind_bufp->indir_arr[ind_bufp->index++];
 		memset(sub_crq, 0, sizeof(*sub_crq));
 		sub_crq->rx_add.first = IBMVNIC_CRQ_CMD;
@@ -405,7 +408,8 @@ static void replenish_rx_pool(struct ibmvnic_adapter *adapter,
 		shift = 8;
 #endif
 		sub_crq->rx_add.len = cpu_to_be32(pool->buff_size << shift);
-		pool->next_free = (pool->next_free + 1) % pool->size;
+
+		/* if send_subcrq_indirect queue is full, flush to VIOS */
 		if (ind_bufp->index == IBMVNIC_MAX_IND_DESCS ||
 		    i == count - 1) {
 			lpar_rc =
-- 
2.26.2

[PATCH net-next v2 2/9] ibmvnic: Fix up some comments and messages

[Sukadev Bhattiprolu]

Add/update some comments/function headers and fix up some messages.

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
Changelog [v2]: [Jakub Kicinski] Fix kdoc issues
---
 drivers/net/ethernet/ibm/ibmvnic.c | 44 ++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index e8b1231be485..cd04c3eb6c41 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -243,14 +243,13 @@ static int alloc_long_term_buff(struct ibmvnic_adapter *adapter,
 
 	rc = ibmvnic_wait_for_completion(adapter, &adapter->fw_done, 10000);
 	if (rc) {
-		dev_err(dev,
-			"Long term map request aborted or timed out,rc = %d\n",
+		dev_err(dev, "LTB map request aborted or timed out, rc = %d\n",
 			rc);
 		goto out;
 	}
 
 	if (adapter->fw_done_rc) {
-		dev_err(dev, "Couldn't map long term buffer,rc = %d\n",
+		dev_err(dev, "Couldn't map LTB, rc = %d\n",
 			adapter->fw_done_rc);
 		rc = -1;
 		goto out;
@@ -281,7 +280,9 @@ static void free_long_term_buff(struct ibmvnic_adapter *adapter,
 	    adapter->reset_reason != VNIC_RESET_MOBILITY &&
 	    adapter->reset_reason != VNIC_RESET_TIMEOUT)
 		send_request_unmap(adapter, ltb->map_id);
+
 	dma_free_coherent(dev, ltb->size, ltb->buff, ltb->addr);
+
 	ltb->buff = NULL;
 	ltb->map_id = 0;
 }
@@ -574,6 +575,12 @@ static int reset_rx_pools(struct ibmvnic_adapter *adapter)
 	return 0;
 }
 
+/**
+ * release_rx_pools() - Release any rx pools attached to @adapter.
+ * @adapter: ibmvnic adapter
+ *
+ * Safe to call this multiple times - even if no pools are attached.
+ */
 static void release_rx_pools(struct ibmvnic_adapter *adapter)
 {
 	struct ibmvnic_rx_pool *rx_pool;
@@ -628,6 +635,9 @@ static int init_rx_pools(struct net_device *netdev)
 		return -1;
 	}
 
+	/* Set num_active_rx_pools early. If we fail below after partial
+	 * allocation, release_rx_pools() will know how many to look for.
+	 */
 	adapter->num_active_rx_pools = rxadd_subcrqs;
 
 	for (i = 0; i < rxadd_subcrqs; i++) {
@@ -646,6 +656,7 @@ static int init_rx_pools(struct net_device *netdev)
 		rx_pool->free_map = kcalloc(rx_pool->size, sizeof(int),
 					    GFP_KERNEL);
 		if (!rx_pool->free_map) {
+			dev_err(dev, "Couldn't alloc free_map %d\n", i);
 			release_rx_pools(adapter);
 			return -1;
 		}
@@ -739,10 +750,19 @@ static void release_one_tx_pool(struct ibmvnic_adapter *adapter,
 	free_long_term_buff(adapter, &tx_pool->long_term_buff);
 }
 
+/**
+ * release_tx_pools() - Release any tx pools attached to @adapter.
+ * @adapter: ibmvnic adapter
+ *
+ * Safe to call this multiple times - even if no pools are attached.
+ */
 static void release_tx_pools(struct ibmvnic_adapter *adapter)
 {
 	int i;
 
+	/* init_tx_pools() ensures that ->tx_pool and ->tso_pool are
+	 * both NULL or both non-NULL. So we only need to check one.
+	 */
 	if (!adapter->tx_pool)
 		return;
 
@@ -793,6 +813,7 @@ static int init_one_tx_pool(struct net_device *netdev,
 static int init_tx_pools(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
+	struct device *dev = &adapter->vdev->dev;
 	int tx_subcrqs;
 	u64 buff_size;
 	int i, rc;
@@ -805,17 +826,27 @@ static int init_tx_pools(struct net_device *netdev)
 
 	adapter->tso_pool = kcalloc(tx_subcrqs,
 				    sizeof(struct ibmvnic_tx_pool), GFP_KERNEL);
+	/* To simplify release_tx_pools() ensure that ->tx_pool and
+	 * ->tso_pool are either both NULL or both non-NULL.
+	 */
 	if (!adapter->tso_pool) {
 		kfree(adapter->tx_pool);
 		adapter->tx_pool = NULL;
 		return -1;
 	}
 
+	/* Set num_active_tx_pools early. If we fail below after partial
+	 * allocation, release_tx_pools() will know how many to look for.
+	 */
 	adapter->num_active_tx_pools = tx_subcrqs;
 
 	for (i = 0; i < tx_subcrqs; i++) {
 		buff_size = adapter->req_mtu + VLAN_HLEN;
 		buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
+
+		dev_dbg(dev, "Init tx pool %d [%llu, %llu]\n",
+			i, adapter->req_tx_entries_per_subcrq, buff_size);
+
 		rc = init_one_tx_pool(netdev, &adapter->tx_pool[i],
 				      adapter->req_tx_entries_per_subcrq,
 				      buff_size);
@@ -4774,9 +4805,10 @@ static void handle_query_map_rsp(union ibmvnic_crq *crq,
 		dev_err(dev, "Error %ld in QUERY_MAP_RSP\n", rc);
 		return;
 	}
-	netdev_dbg(netdev, "page_size = %d\ntot_pages = %d\nfree_pages = %d\n",
-		   crq->query_map_rsp.page_size, crq->query_map_rsp.tot_pages,
-		   crq->query_map_rsp.free_pages);
+	netdev_dbg(netdev, "page_size = %d\ntot_pages = %u\nfree_pages = %u\n",
+		   crq->query_map_rsp.page_size,
+		   __be32_to_cpu(crq->query_map_rsp.tot_pages),
+		   __be32_to_cpu(crq->query_map_rsp.free_pages));
 }
 
 static void handle_query_cap_rsp(union ibmvnic_crq *crq,
-- 
2.26.2

[PATCH net-next v2 3/9] ibmvnic: Use/rename local vars in init_rx_pools

[Sukadev Bhattiprolu]

To make the code more readable, use/rename some local variables.
Basically we have a set of pools, num_pools. Each pool has a set of
buffers, pool_size and each buffer is of size buff_size.

pool_size is a bit ambiguous (whether size in bytes or buffers). Add
a comment in the header file to make it explicit.

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 17 +++++++++--------
 drivers/net/ethernet/ibm/ibmvnic.h |  2 +-
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index cd04c3eb6c41..688489475791 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -620,14 +620,16 @@ static int init_rx_pools(struct net_device *netdev)
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
 	struct device *dev = &adapter->vdev->dev;
 	struct ibmvnic_rx_pool *rx_pool;
-	int rxadd_subcrqs;
+	u64 num_pools;
+	u64 pool_size;		/* # of buffers in one pool */
 	u64 buff_size;
 	int i, j;
 
-	rxadd_subcrqs = adapter->num_active_rx_scrqs;
+	num_pools = adapter->num_active_rx_scrqs;
+	pool_size = adapter->req_rx_add_entries_per_subcrq;
 	buff_size = adapter->cur_rx_buf_sz;
 
-	adapter->rx_pool = kcalloc(rxadd_subcrqs,
+	adapter->rx_pool = kcalloc(num_pools,
 				   sizeof(struct ibmvnic_rx_pool),
 				   GFP_KERNEL);
 	if (!adapter->rx_pool) {
@@ -638,17 +640,16 @@ static int init_rx_pools(struct net_device *netdev)
 	/* Set num_active_rx_pools early. If we fail below after partial
 	 * allocation, release_rx_pools() will know how many to look for.
 	 */
-	adapter->num_active_rx_pools = rxadd_subcrqs;
+	adapter->num_active_rx_pools = num_pools;
 
-	for (i = 0; i < rxadd_subcrqs; i++) {
+	for (i = 0; i < num_pools; i++) {
 		rx_pool = &adapter->rx_pool[i];
 
 		netdev_dbg(adapter->netdev,
 			   "Initializing rx_pool[%d], %lld buffs, %lld bytes each\n",
-			   i, adapter->req_rx_add_entries_per_subcrq,
-			   buff_size);
+			   i, pool_size, buff_size);
 
-		rx_pool->size = adapter->req_rx_add_entries_per_subcrq;
+		rx_pool->size = pool_size;
 		rx_pool->index = i;
 		rx_pool->buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
 		rx_pool->active = 1;
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 22df602323bc..5652566818fb 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -827,7 +827,7 @@ struct ibmvnic_rx_buff {
 
 struct ibmvnic_rx_pool {
 	struct ibmvnic_rx_buff *rx_buff;
-	int size;
+	int size;			/* # of buffers in the pool */
 	int index;
 	int buff_size;
 	atomic_t available;
-- 
2.26.2

[PATCH net-next v2 4/9] ibmvnic: Use/rename local vars in init_tx_pools

[Sukadev Bhattiprolu]

Use/rename local variables in init_tx_pools() for consistency with
init_rx_pools() and for readability. Also add some comments

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 688489475791..97041b319beb 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -781,31 +781,31 @@ static void release_tx_pools(struct ibmvnic_adapter *adapter)
 
 static int init_one_tx_pool(struct net_device *netdev,
 			    struct ibmvnic_tx_pool *tx_pool,
-			    int num_entries, int buf_size)
+			    int pool_size, int buf_size)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
 	int i;
 
-	tx_pool->tx_buff = kcalloc(num_entries,
+	tx_pool->tx_buff = kcalloc(pool_size,
 				   sizeof(struct ibmvnic_tx_buff),
 				   GFP_KERNEL);
 	if (!tx_pool->tx_buff)
 		return -1;
 
 	if (alloc_long_term_buff(adapter, &tx_pool->long_term_buff,
-				 num_entries * buf_size))
+				 pool_size * buf_size))
 		return -1;
 
-	tx_pool->free_map = kcalloc(num_entries, sizeof(int), GFP_KERNEL);
+	tx_pool->free_map = kcalloc(pool_size, sizeof(int), GFP_KERNEL);
 	if (!tx_pool->free_map)
 		return -1;
 
-	for (i = 0; i < num_entries; i++)
+	for (i = 0; i < pool_size; i++)
 		tx_pool->free_map[i] = i;
 
 	tx_pool->consumer_index = 0;
 	tx_pool->producer_index = 0;
-	tx_pool->num_buffers = num_entries;
+	tx_pool->num_buffers = pool_size;
 	tx_pool->buf_size = buf_size;
 
 	return 0;
@@ -815,17 +815,20 @@ static int init_tx_pools(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
 	struct device *dev = &adapter->vdev->dev;
-	int tx_subcrqs;
+	int num_pools;
+	u64 pool_size;		/* # of buffers in pool */
 	u64 buff_size;
 	int i, rc;
 
-	tx_subcrqs = adapter->num_active_tx_scrqs;
-	adapter->tx_pool = kcalloc(tx_subcrqs,
+	pool_size = adapter->req_tx_entries_per_subcrq;
+	num_pools = adapter->num_active_tx_scrqs;
+
+	adapter->tx_pool = kcalloc(num_pools,
 				   sizeof(struct ibmvnic_tx_pool), GFP_KERNEL);
 	if (!adapter->tx_pool)
 		return -1;
 
-	adapter->tso_pool = kcalloc(tx_subcrqs,
+	adapter->tso_pool = kcalloc(num_pools,
 				    sizeof(struct ibmvnic_tx_pool), GFP_KERNEL);
 	/* To simplify release_tx_pools() ensure that ->tx_pool and
 	 * ->tso_pool are either both NULL or both non-NULL.
@@ -839,9 +842,9 @@ static int init_tx_pools(struct net_device *netdev)
 	/* Set num_active_tx_pools early. If we fail below after partial
 	 * allocation, release_tx_pools() will know how many to look for.
 	 */
-	adapter->num_active_tx_pools = tx_subcrqs;
+	adapter->num_active_tx_pools = num_pools;
 
-	for (i = 0; i < tx_subcrqs; i++) {
+	for (i = 0; i < num_pools; i++) {
 		buff_size = adapter->req_mtu + VLAN_HLEN;
 		buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
 
@@ -849,8 +852,7 @@ static int init_tx_pools(struct net_device *netdev)
 			i, adapter->req_tx_entries_per_subcrq, buff_size);
 
 		rc = init_one_tx_pool(netdev, &adapter->tx_pool[i],
-				      adapter->req_tx_entries_per_subcrq,
-				      buff_size);
+				      pool_size, buff_size);
 		if (rc) {
 			release_tx_pools(adapter);
 			return rc;
-- 
2.26.2

[PATCH net-next v2 5/9] ibmvnic: init_tx_pools move loop-invariant code

[Sukadev Bhattiprolu]

In init_tx_pools() move some loop-invariant code out of the loop.

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 97041b319beb..bb9b8aec9c9b 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -843,11 +843,10 @@ static int init_tx_pools(struct net_device *netdev)
 	 * allocation, release_tx_pools() will know how many to look for.
 	 */
 	adapter->num_active_tx_pools = num_pools;
+	buff_size = adapter->req_mtu + VLAN_HLEN;
+	buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
 
 	for (i = 0; i < num_pools; i++) {
-		buff_size = adapter->req_mtu + VLAN_HLEN;
-		buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
-
 		dev_dbg(dev, "Init tx pool %d [%llu, %llu]\n",
 			i, adapter->req_tx_entries_per_subcrq, buff_size);
 
-- 
2.26.2

[PATCH net-next v2 6/9] ibmvnic: Use bitmap for LTB map_ids

[Sukadev Bhattiprolu]

In a follow-on patch, we will reuse long term buffers when possible.
When doing so we have to be careful to properly assign map ids. We
can no longer assign them sequentially because a lower map id may be
available and we could wrap at 255 and collide with an in-use map id.

Instead, use a bitmap to track active map ids and to find a free map id.
Don't need to take locks here since the map_id only changes during reset
and at that time only the reset worker thread should be using the adapter.

Noticed this when analyzing an error Dany Madden ran into with the
patch set.

Reported-by: Dany Madden <drt@linux.ibm.com>
Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 12 ++++++++----
 drivers/net/ethernet/ibm/ibmvnic.h |  3 ++-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index bb9b8aec9c9b..4603597a9c10 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -228,8 +228,9 @@ static int alloc_long_term_buff(struct ibmvnic_adapter *adapter,
 		dev_err(dev, "Couldn't alloc long term buffer\n");
 		return -ENOMEM;
 	}
-	ltb->map_id = adapter->map_id;
-	adapter->map_id++;
+	ltb->map_id = find_first_zero_bit(adapter->map_ids,
+					  MAX_MAP_ID);
+	bitmap_set(adapter->map_ids, ltb->map_id, 1);
 
 	mutex_lock(&adapter->fw_lock);
 	adapter->fw_done_rc = 0;
@@ -284,6 +285,8 @@ static void free_long_term_buff(struct ibmvnic_adapter *adapter,
 	dma_free_coherent(dev, ltb->size, ltb->buff, ltb->addr);
 
 	ltb->buff = NULL;
+	/* mark this map_id free */
+	bitmap_clear(adapter->map_ids, ltb->map_id, 1);
 	ltb->map_id = 0;
 }
 
@@ -1235,8 +1238,6 @@ static int init_resources(struct ibmvnic_adapter *adapter)
 		return rc;
 	}
 
-	adapter->map_id = 1;
-
 	rc = init_napi(adapter);
 	if (rc)
 		return rc;
@@ -5557,6 +5558,9 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	adapter->vdev = dev;
 	adapter->netdev = netdev;
 	adapter->login_pending = false;
+	memset(&adapter->map_ids, 0, sizeof(adapter->map_ids));
+	/* map_ids start at 1, so ensure map_id 0 is always "in-use" */
+	bitmap_set(adapter->map_ids, 0, 1);
 
 	ether_addr_copy(adapter->mac_addr, mac_addr_p);
 	ether_addr_copy(netdev->dev_addr, adapter->mac_addr);
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 5652566818fb..e97f1aa98c05 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -979,7 +979,8 @@ struct ibmvnic_adapter {
 	u64 opt_tx_entries_per_subcrq;
 	u64 opt_rxba_entries_per_subcrq;
 	__be64 tx_rx_desc_req;
-	u8 map_id;
+#define MAX_MAP_ID	255
+	DECLARE_BITMAP(map_ids, MAX_MAP_ID);
 	u32 num_active_rx_scrqs;
 	u32 num_active_rx_pools;
 	u32 num_active_rx_napi;
-- 
2.26.2

[PATCH net-next v2 7/9] ibmvnic: Reuse LTB when possible

[Sukadev Bhattiprolu]

Reuse the long term buffer during a reset as long as its size has
not changed. If the size has changed, free it and allocate a new
one of the appropriate size.

When we do this, alloc_long_term_buff() and reset_long_term_buff()
become identical. Drop reset_long_term_buff().

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
Changelog[v2]: [Jakub Kicinski] Fix kdoc issues
---
 drivers/net/ethernet/ibm/ibmvnic.c | 137 ++++++++++++++++-------------
 1 file changed, 74 insertions(+), 63 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 4603597a9c10..dafb36690fdc 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -108,6 +108,8 @@ static int init_crq_queue(struct ibmvnic_adapter *adapter);
 static int send_query_phys_parms(struct ibmvnic_adapter *adapter);
 static void ibmvnic_tx_scrq_clean_buffer(struct ibmvnic_adapter *adapter,
 					 struct ibmvnic_sub_crq_queue *tx_scrq);
+static void free_long_term_buff(struct ibmvnic_adapter *adapter,
+				struct ibmvnic_long_term_buff *ltb);
 
 struct ibmvnic_stat {
 	char name[ETH_GSTRING_LEN];
@@ -214,23 +216,77 @@ static int ibmvnic_wait_for_completion(struct ibmvnic_adapter *adapter,
 	return -ETIMEDOUT;
 }
 
+/**
+ * reuse_ltb() - Check if a long term buffer can be reused
+ * @ltb:  The long term buffer to be checked
+ * @size: The size of the long term buffer.
+ *
+ * An LTB can be reused unless its size has changed.
+ *
+ * Return: Return true if the LTB can be reused, false otherwise.
+ */
+static bool reuse_ltb(struct ibmvnic_long_term_buff *ltb, int size)
+{
+	return (ltb->buff && ltb->size == size);
+}
+
+/**
+ * alloc_long_term_buff() - Allocate a long term buffer (LTB)
+ *
+ * @adapter: ibmvnic adapter associated to the LTB
+ * @ltb:     container object for the LTB
+ * @size:    size of the LTB
+ *
+ * Allocate an LTB of the specified size and notify VIOS.
+ *
+ * If the given @ltb already has the correct size, reuse it. Otherwise if
+ * its non-NULL, free it. Then allocate a new one of the correct size.
+ * Notify the VIOS either way since we may now be working with a new VIOS.
+ *
+ * Allocating larger chunks of memory during resets, specially LPM or under
+ * low memory situations can cause resets to fail/timeout and for LPAR to
+ * lose connectivity. So hold onto the LTB even if we fail to communicate
+ * with the VIOS and reuse it on next open. Free LTB when adapter is closed.
+ *
+ * Return: 0 if we were able to allocate the LTB and notify the VIOS and
+ *	   a negative value otherwise.
+ */
 static int alloc_long_term_buff(struct ibmvnic_adapter *adapter,
 				struct ibmvnic_long_term_buff *ltb, int size)
 {
 	struct device *dev = &adapter->vdev->dev;
 	int rc;
 
-	ltb->size = size;
-	ltb->buff = dma_alloc_coherent(dev, ltb->size, &ltb->addr,
-				       GFP_KERNEL);
+	if (!reuse_ltb(ltb, size)) {
+		dev_dbg(dev,
+			"LTB size changed from 0x%llx to 0x%x, reallocating\n",
+			 ltb->size, size);
+		free_long_term_buff(adapter, ltb);
+	}
 
-	if (!ltb->buff) {
-		dev_err(dev, "Couldn't alloc long term buffer\n");
-		return -ENOMEM;
+	if (ltb->buff) {
+		dev_dbg(dev, "Reusing LTB [map %d, size 0x%llx]\n",
+			ltb->map_id, ltb->size);
+	} else {
+		ltb->buff = dma_alloc_coherent(dev, size, &ltb->addr,
+					       GFP_KERNEL);
+		if (!ltb->buff) {
+			dev_err(dev, "Couldn't alloc long term buffer\n");
+			return -ENOMEM;
+		}
+		ltb->size = size;
+
+		ltb->map_id = find_first_zero_bit(adapter->map_ids,
+						  MAX_MAP_ID);
+		bitmap_set(adapter->map_ids, ltb->map_id, 1);
+
+		dev_dbg(dev,
+			"Allocated new LTB [map %d, size 0x%llx]\n",
+			 ltb->map_id, ltb->size);
 	}
-	ltb->map_id = find_first_zero_bit(adapter->map_ids,
-					  MAX_MAP_ID);
-	bitmap_set(adapter->map_ids, ltb->map_id, 1);
+
+	/* Ensure ltb is zeroed - specially when reusing it. */
+	memset(ltb->buff, 0, ltb->size);
 
 	mutex_lock(&adapter->fw_lock);
 	adapter->fw_done_rc = 0;
@@ -257,10 +313,7 @@ static int alloc_long_term_buff(struct ibmvnic_adapter *adapter,
 	}
 	rc = 0;
 out:
-	if (rc) {
-		dma_free_coherent(dev, ltb->size, ltb->buff, ltb->addr);
-		ltb->buff = NULL;
-	}
+	/* don't free LTB on communication error - see function header */
 	mutex_unlock(&adapter->fw_lock);
 	return rc;
 }
@@ -290,43 +343,6 @@ static void free_long_term_buff(struct ibmvnic_adapter *adapter,
 	ltb->map_id = 0;
 }
 
-static int reset_long_term_buff(struct ibmvnic_adapter *adapter,
-				struct ibmvnic_long_term_buff *ltb)
-{
-	struct device *dev = &adapter->vdev->dev;
-	int rc;
-
-	memset(ltb->buff, 0, ltb->size);
-
-	mutex_lock(&adapter->fw_lock);
-	adapter->fw_done_rc = 0;
-
-	reinit_completion(&adapter->fw_done);
-	rc = send_request_map(adapter, ltb->addr, ltb->size, ltb->map_id);
-	if (rc) {
-		mutex_unlock(&adapter->fw_lock);
-		return rc;
-	}
-
-	rc = ibmvnic_wait_for_completion(adapter, &adapter->fw_done, 10000);
-	if (rc) {
-		dev_info(dev,
-			 "Reset failed, long term map request timed out or aborted\n");
-		mutex_unlock(&adapter->fw_lock);
-		return rc;
-	}
-
-	if (adapter->fw_done_rc) {
-		dev_info(dev,
-			 "Reset failed, attempting to free and reallocate buffer\n");
-		free_long_term_buff(adapter, ltb);
-		mutex_unlock(&adapter->fw_lock);
-		return alloc_long_term_buff(adapter, ltb, ltb->size);
-	}
-	mutex_unlock(&adapter->fw_lock);
-	return 0;
-}
-
 static void deactivate_rx_pools(struct ibmvnic_adapter *adapter)
 {
 	int i;
@@ -548,18 +564,10 @@ static int reset_rx_pools(struct ibmvnic_adapter *adapter)
 
 		netdev_dbg(adapter->netdev, "Re-setting rx_pool[%d]\n", i);
 
-		if (rx_pool->buff_size != buff_size) {
-			free_long_term_buff(adapter, &rx_pool->long_term_buff);
-			rx_pool->buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
-			rc = alloc_long_term_buff(adapter,
-						  &rx_pool->long_term_buff,
-						  rx_pool->size *
-						  rx_pool->buff_size);
-		} else {
-			rc = reset_long_term_buff(adapter,
-						  &rx_pool->long_term_buff);
-		}
-
+		rx_pool->buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
+		rc = alloc_long_term_buff(adapter,
+					  &rx_pool->long_term_buff,
+					  rx_pool->size * rx_pool->buff_size);
 		if (rc)
 			return rc;
 
@@ -694,9 +702,12 @@ static int init_rx_pools(struct net_device *netdev)
 static int reset_one_tx_pool(struct ibmvnic_adapter *adapter,
 			     struct ibmvnic_tx_pool *tx_pool)
 {
+	struct ibmvnic_long_term_buff *ltb;
 	int rc, i;
 
-	rc = reset_long_term_buff(adapter, &tx_pool->long_term_buff);
+	ltb = &tx_pool->long_term_buff;
+
+	rc = alloc_long_term_buff(adapter, ltb, ltb->size);
 	if (rc)
 		return rc;
 
-- 
2.26.2

[PATCH net-next v2 8/9] ibmvnic: Reuse rx pools when possible

[Sukadev Bhattiprolu]

Rather than releasing the rx pools on and reallocating them on every
reset, reuse the rx pools unless the pool parameters (number of pools,
size of each pool or size of each buffer in a pool) have changed.

If the pool parameters changed, then release the old pools (if any)
and allocate new ones.

Specifically release rx pools, if:
	- adapter is removed,
	- pool parameters change during reset,
	- we encounter an error when opening the adapter in response
	  to a user request (in ibmvnic_open()).

and don't release them:
	- in __ibmvnic_close() or
	- on errors in __ibmvnic_open()

in the hope that we can reuse them on the next reset.

With these, reset_rx_pools() can be dropped because its optimzation is
now included in init_rx_pools() itself.

cleanup_rx_pools() releases all the skbs associated with the pool and
is called from ibmvnic_cleanup(), which is called on every reset. Since
we want to reuse skbs across resets, move cleanup_rx_pools() out of
ibmvnic_cleanup() and call it only when user closes the adapter.

Add two new adapter fields, ->prev_rx_buf_sz, ->prev_rx_pool_size to
keep track of the previous values and use them to decide whether to
reuse or realloc the pools.

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
Changelog[v2]: [Jakub Kicinski] Fix kdoc issues
---
 drivers/net/ethernet/ibm/ibmvnic.c | 198 +++++++++++++++++++----------
 drivers/net/ethernet/ibm/ibmvnic.h |   3 +
 2 files changed, 137 insertions(+), 64 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index dafb36690fdc..05aabb0effef 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -383,20 +383,27 @@ static void replenish_rx_pool(struct ibmvnic_adapter *adapter,
 	 * be 0.
 	 */
 	for (i = ind_bufp->index; i < count; ++i) {
-		skb = netdev_alloc_skb(adapter->netdev, pool->buff_size);
+		index = pool->free_map[pool->next_free];
+
+		/* We maybe reusing the skb from earlier resets. Allocate
+		 * only if necessary. But since the LTB may have changed
+		 * during reset (see init_rx_pools()), update LTB below
+		 * even if reusing skb.
+		 */
+		skb = pool->rx_buff[index].skb;
 		if (!skb) {
-			dev_err(dev, "Couldn't replenish rx buff\n");
-			adapter->replenish_no_mem++;
-			break;
+			skb = netdev_alloc_skb(adapter->netdev,
+					       pool->buff_size);
+			if (!skb) {
+				dev_err(dev, "Couldn't replenish rx buff\n");
+				adapter->replenish_no_mem++;
+				break;
+			}
 		}
 
-		index = pool->free_map[pool->next_free];
 		pool->free_map[pool->next_free] = IBMVNIC_INVALID_MAP;
 		pool->next_free = (pool->next_free + 1) % pool->size;
 
-		if (pool->rx_buff[index].skb)
-			dev_err(dev, "Inconsistent free_map!\n");
-
 		/* Copy the skb to the long term mapped DMA buffer */
 		offset = index * pool->buff_size;
 		dst = pool->long_term_buff.buff + offset;
@@ -547,45 +554,6 @@ static int init_stats_token(struct ibmvnic_adapter *adapter)
 	return 0;
 }
 
-static int reset_rx_pools(struct ibmvnic_adapter *adapter)
-{
-	struct ibmvnic_rx_pool *rx_pool;
-	u64 buff_size;
-	int rx_scrqs;
-	int i, j, rc;
-
-	if (!adapter->rx_pool)
-		return -1;
-
-	buff_size = adapter->cur_rx_buf_sz;
-	rx_scrqs = adapter->num_active_rx_pools;
-	for (i = 0; i < rx_scrqs; i++) {
-		rx_pool = &adapter->rx_pool[i];
-
-		netdev_dbg(adapter->netdev, "Re-setting rx_pool[%d]\n", i);
-
-		rx_pool->buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
-		rc = alloc_long_term_buff(adapter,
-					  &rx_pool->long_term_buff,
-					  rx_pool->size * rx_pool->buff_size);
-		if (rc)
-			return rc;
-
-		for (j = 0; j < rx_pool->size; j++)
-			rx_pool->free_map[j] = j;
-
-		memset(rx_pool->rx_buff, 0,
-		       rx_pool->size * sizeof(struct ibmvnic_rx_buff));
-
-		atomic_set(&rx_pool->available, 0);
-		rx_pool->next_alloc = 0;
-		rx_pool->next_free = 0;
-		rx_pool->active = 1;
-	}
-
-	return 0;
-}
-
 /**
  * release_rx_pools() - Release any rx pools attached to @adapter.
  * @adapter: ibmvnic adapter
@@ -606,6 +574,7 @@ static void release_rx_pools(struct ibmvnic_adapter *adapter)
 		netdev_dbg(adapter->netdev, "Releasing rx_pool[%d]\n", i);
 
 		kfree(rx_pool->free_map);
+
 		free_long_term_buff(adapter, &rx_pool->long_term_buff);
 
 		if (!rx_pool->rx_buff)
@@ -624,8 +593,68 @@ static void release_rx_pools(struct ibmvnic_adapter *adapter)
 	kfree(adapter->rx_pool);
 	adapter->rx_pool = NULL;
 	adapter->num_active_rx_pools = 0;
+	adapter->prev_rx_pool_size = 0;
+}
+
+/**
+ * reuse_rx_pools() - Check if the existing rx pools can be reused.
+ * @adapter: ibmvnic adapter
+ *
+ * Check if the existing rx pools in the adapter can be reused. The
+ * pools can be reused if the pool parameters (number of pools,
+ * number of buffers in the pool and size of each buffer) have not
+ * changed.
+ *
+ * NOTE: This assumes that all pools have the same number of buffers
+ *       which is the case currently. If that changes, we must fix this.
+ *
+ * Return: true if the rx pools can be reused, false otherwise.
+ */
+static bool reuse_rx_pools(struct ibmvnic_adapter *adapter)
+{
+	u64 old_num_pools, new_num_pools;
+	u64 old_pool_size, new_pool_size;
+	u64 old_buff_size, new_buff_size;
+
+	if (!adapter->rx_pool)
+		return false;
+
+	old_num_pools = adapter->num_active_rx_pools;
+	new_num_pools = adapter->req_rx_queues;
+
+	old_pool_size = adapter->prev_rx_pool_size;
+	new_pool_size = adapter->req_rx_add_entries_per_subcrq;
+
+	old_buff_size = adapter->prev_rx_buf_sz;
+	new_buff_size = adapter->cur_rx_buf_sz;
+
+	/* Require buff size to be exactly same for now */
+	if (old_buff_size != new_buff_size)
+		return false;
+
+	if (old_num_pools == new_num_pools && old_pool_size == new_pool_size)
+		return true;
+
+	if (old_num_pools < adapter->min_rx_queues ||
+	    old_num_pools > adapter->max_rx_queues ||
+	    old_pool_size < adapter->min_rx_add_entries_per_subcrq ||
+	    old_pool_size > adapter->max_rx_add_entries_per_subcrq)
+		return false;
+
+	return true;
 }
 
+/**
+ * init_rx_pools(): Initialize the set of receiver pools in the adapter.
+ * @netdev: net device associated with the vnic interface
+ *
+ * Initialize the set of receiver pools in the ibmvnic adapter associated
+ * with the net_device @netdev. If possible, reuse the existing rx pools.
+ * Otherwise free any existing pools and  allocate a new set of pools
+ * before initializing them.
+ *
+ * Return: 0 on success and negative value on error.
+ */
 static int init_rx_pools(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
@@ -636,10 +665,18 @@ static int init_rx_pools(struct net_device *netdev)
 	u64 buff_size;
 	int i, j;
 
-	num_pools = adapter->num_active_rx_scrqs;
 	pool_size = adapter->req_rx_add_entries_per_subcrq;
+	num_pools = adapter->req_rx_queues;
 	buff_size = adapter->cur_rx_buf_sz;
 
+	if (reuse_rx_pools(adapter)) {
+		dev_dbg(dev, "Reusing rx pools\n");
+		goto update_ltb;
+	}
+
+	/* Allocate/populate the pools. */
+	release_rx_pools(adapter);
+
 	adapter->rx_pool = kcalloc(num_pools,
 				   sizeof(struct ibmvnic_rx_pool),
 				   GFP_KERNEL);
@@ -663,14 +700,12 @@ static int init_rx_pools(struct net_device *netdev)
 		rx_pool->size = pool_size;
 		rx_pool->index = i;
 		rx_pool->buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
-		rx_pool->active = 1;
 
 		rx_pool->free_map = kcalloc(rx_pool->size, sizeof(int),
 					    GFP_KERNEL);
 		if (!rx_pool->free_map) {
 			dev_err(dev, "Couldn't alloc free_map %d\n", i);
-			release_rx_pools(adapter);
-			return -1;
+			goto out_release;
 		}
 
 		rx_pool->rx_buff = kcalloc(rx_pool->size,
@@ -678,25 +713,58 @@ static int init_rx_pools(struct net_device *netdev)
 					   GFP_KERNEL);
 		if (!rx_pool->rx_buff) {
 			dev_err(dev, "Couldn't alloc rx buffers\n");
-			release_rx_pools(adapter);
-			return -1;
+			goto out_release;
 		}
+	}
+
+	adapter->prev_rx_pool_size = pool_size;
+	adapter->prev_rx_buf_sz = adapter->cur_rx_buf_sz;
+
+update_ltb:
+	for (i = 0; i < num_pools; i++) {
+		rx_pool = &adapter->rx_pool[i];
+		dev_dbg(dev, "Updating LTB for rx pool %d [%d, %d]\n",
+			i, rx_pool->size, rx_pool->buff_size);
 
 		if (alloc_long_term_buff(adapter, &rx_pool->long_term_buff,
-					 rx_pool->size * rx_pool->buff_size)) {
-			release_rx_pools(adapter);
-			return -1;
-		}
+					 rx_pool->size * rx_pool->buff_size))
+			goto out;
+
+		for (j = 0; j < rx_pool->size; ++j) {
+			struct ibmvnic_rx_buff *rx_buff;
 
-		for (j = 0; j < rx_pool->size; ++j)
 			rx_pool->free_map[j] = j;
 
+			/* NOTE: Don't clear rx_buff->skb here - will leak
+			 * memory! replenish_rx_pool() will reuse skbs or
+			 * allocate as necessary.
+			 */
+			rx_buff = &rx_pool->rx_buff[j];
+			rx_buff->dma = 0;
+			rx_buff->data = 0;
+			rx_buff->size = 0;
+			rx_buff->pool_index = 0;
+		}
+
+		/* Mark pool "empty" so replenish_rx_pools() will
+		 * update the LTB info for each buffer
+		 */
 		atomic_set(&rx_pool->available, 0);
 		rx_pool->next_alloc = 0;
 		rx_pool->next_free = 0;
+		/* replenish_rx_pool() may have called deactivate_rx_pools()
+		 * on failover. Ensure pool is active now.
+		 */
+		rx_pool->active = 1;
 	}
-
 	return 0;
+out_release:
+	release_rx_pools(adapter);
+out:
+	/* We failed to allocate one or more LTBs or map them on the VIOS.
+	 * Hold onto the pools and any LTBs that we did allocate/map.
+	 */
+	return -1;
 }
 
 static int reset_one_tx_pool(struct ibmvnic_adapter *adapter,
@@ -1072,7 +1140,6 @@ static void release_resources(struct ibmvnic_adapter *adapter)
 	release_vpd_data(adapter);
 
 	release_tx_pools(adapter);
-	release_rx_pools(adapter);
 
 	release_napi(adapter);
 	release_login_buffer(adapter);
@@ -1345,6 +1412,7 @@ static int ibmvnic_open(struct net_device *netdev)
 		if (rc) {
 			netdev_err(netdev, "failed to initialize resources\n");
 			release_resources(adapter);
+			release_rx_pools(adapter);
 			goto out;
 		}
 	}
@@ -1474,7 +1542,6 @@ static void ibmvnic_cleanup(struct net_device *netdev)
 	ibmvnic_napi_disable(adapter);
 	ibmvnic_disable_irqs(adapter);
 
-	clean_rx_pools(adapter);
 	clean_tx_pools(adapter);
 }
 
@@ -1509,6 +1576,7 @@ static int ibmvnic_close(struct net_device *netdev)
 
 	rc = __ibmvnic_close(netdev);
 	ibmvnic_cleanup(netdev);
+	clean_rx_pools(adapter);
 
 	return rc;
 }
@@ -2237,7 +2305,6 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 		    !adapter->rx_pool ||
 		    !adapter->tso_pool ||
 		    !adapter->tx_pool) {
-			release_rx_pools(adapter);
 			release_tx_pools(adapter);
 			release_napi(adapter);
 			release_vpd_data(adapter);
@@ -2254,9 +2321,10 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 				goto out;
 			}
 
-			rc = reset_rx_pools(adapter);
+			rc = init_rx_pools(netdev);
 			if (rc) {
-				netdev_dbg(adapter->netdev, "reset rx pools failed (%d)\n",
+				netdev_dbg(netdev,
+					   "init rx pools failed (%d)\n",
 					   rc);
 				goto out;
 			}
@@ -5592,6 +5660,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	init_completion(&adapter->reset_done);
 	init_completion(&adapter->stats_done);
 	clear_bit(0, &adapter->resetting);
+	adapter->prev_rx_buf_sz = 0;
 
 	init_success = false;
 	do {
@@ -5692,6 +5761,7 @@ static void ibmvnic_remove(struct vio_dev *dev)
 	unregister_netdevice(netdev);
 
 	release_resources(adapter);
+	release_rx_pools(adapter);
 	release_sub_crqs(adapter, 1);
 	release_crq_queue(adapter);
 
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index e97f1aa98c05..b73a1b812368 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -986,7 +986,10 @@ struct ibmvnic_adapter {
 	u32 num_active_rx_napi;
 	u32 num_active_tx_scrqs;
 	u32 num_active_tx_pools;
+
+	u32 prev_rx_pool_size;
 	u32 cur_rx_buf_sz;
+	u32 prev_rx_buf_sz;
 
 	struct tasklet_struct tasklet;
 	enum vnic_state state;
-- 
2.26.2

[PATCH net-next v2 9/9] ibmvnic: Reuse tx pools when possible

[Sukadev Bhattiprolu]

Rather than releasing the tx pools on every close and reallocating
them on open, reuse the tx pools unless the pool parameters (number
of pools, size of each pool or size of each buffer in a pool) have
changed.

If the pool parameters changed, then release the old pools (if
any) and allocate new ones.

Specifically release tx pools, if:
	- adapter is removed,
	- pool parameters change during reset,
	- we encounter an error when opening the adapter in response
	  to a user request (in ibmvnic_open()).

and don't release them:
	- in __ibmvnic_close() or
	- on errors in __ibmvnic_open()

in the hope that we can reuse them during this or next reset.

With these changes reset_tx_pools() can be dropped because its
optimization is now included in init_tx_pools() itself.

cleanup_tx_pools() releases all the skbs associated with the pool and
is called from ibmvnic_cleanup(), which is called on every reset. Since
we want to reuse skbs across resets, move cleanup_tx_pools() out of
ibmvnic_cleanup() and call it only when user closes the adapter.

Add two new adapter fields, ->prev_mtu, ->prev_tx_pool_size to track the
previous values and use them to decide whether to reuse or realloc the
pools.

Reviewed-by: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
Changelog[v2]: [Jakub Kicinski] Fix kdoc issues
---
 drivers/net/ethernet/ibm/ibmvnic.c | 215 +++++++++++++++++++----------
 drivers/net/ethernet/ibm/ibmvnic.h |   2 +
 2 files changed, 147 insertions(+), 70 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 05aabb0effef..d1be883f933a 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -767,53 +767,6 @@ static int init_rx_pools(struct net_device *netdev)
 	return -1;
 }
 
-static int reset_one_tx_pool(struct ibmvnic_adapter *adapter,
-			     struct ibmvnic_tx_pool *tx_pool)
-{
-	struct ibmvnic_long_term_buff *ltb;
-	int rc, i;
-
-	ltb = &tx_pool->long_term_buff;
-
-	rc = alloc_long_term_buff(adapter, ltb, ltb->size);
-	if (rc)
-		return rc;
-
-	memset(tx_pool->tx_buff, 0,
-	       tx_pool->num_buffers *
-	       sizeof(struct ibmvnic_tx_buff));
-
-	for (i = 0; i < tx_pool->num_buffers; i++)
-		tx_pool->free_map[i] = i;
-
-	tx_pool->consumer_index = 0;
-	tx_pool->producer_index = 0;
-
-	return 0;
-}
-
-static int reset_tx_pools(struct ibmvnic_adapter *adapter)
-{
-	int tx_scrqs;
-	int i, rc;
-
-	if (!adapter->tx_pool)
-		return -1;
-
-	tx_scrqs = adapter->num_active_tx_pools;
-	for (i = 0; i < tx_scrqs; i++) {
-		ibmvnic_tx_scrq_clean_buffer(adapter, adapter->tx_scrq[i]);
-		rc = reset_one_tx_pool(adapter, &adapter->tso_pool[i]);
-		if (rc)
-			return rc;
-		rc = reset_one_tx_pool(adapter, &adapter->tx_pool[i]);
-		if (rc)
-			return rc;
-	}
-
-	return 0;
-}
-
 static void release_vpd_data(struct ibmvnic_adapter *adapter)
 {
 	if (!adapter->vpd)
@@ -859,13 +812,13 @@ static void release_tx_pools(struct ibmvnic_adapter *adapter)
 	kfree(adapter->tso_pool);
 	adapter->tso_pool = NULL;
 	adapter->num_active_tx_pools = 0;
+	adapter->prev_tx_pool_size = 0;
 }
 
 static int init_one_tx_pool(struct net_device *netdev,
 			    struct ibmvnic_tx_pool *tx_pool,
 			    int pool_size, int buf_size)
 {
-	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
 	int i;
 
 	tx_pool->tx_buff = kcalloc(pool_size,
@@ -874,13 +827,12 @@ static int init_one_tx_pool(struct net_device *netdev,
 	if (!tx_pool->tx_buff)
 		return -1;
 
-	if (alloc_long_term_buff(adapter, &tx_pool->long_term_buff,
-				 pool_size * buf_size))
-		return -1;
-
 	tx_pool->free_map = kcalloc(pool_size, sizeof(int), GFP_KERNEL);
-	if (!tx_pool->free_map)
+	if (!tx_pool->free_map) {
+		kfree(tx_pool->tx_buff);
+		tx_pool->tx_buff = NULL;
 		return -1;
+	}
 
 	for (i = 0; i < pool_size; i++)
 		tx_pool->free_map[i] = i;
@@ -893,6 +845,62 @@ static int init_one_tx_pool(struct net_device *netdev,
 	return 0;
 }
 
+/**
+ * reuse_tx_pools() - Check if the existing tx pools can be reused.
+ * @adapter: ibmvnic adapter
+ *
+ * Check if the existing tx pools in the adapter can be reused. The
+ * pools can be reused if the pool parameters (number of pools,
+ * number of buffers in the pool and mtu) have not changed.
+ *
+ * NOTE: This assumes that all pools have the same number of buffers
+ *       which is the case currently. If that changes, we must fix this.
+ *
+ * Return: true if the tx pools can be reused, false otherwise.
+ */
+static bool reuse_tx_pools(struct ibmvnic_adapter *adapter)
+{
+	u64 old_num_pools, new_num_pools;
+	u64 old_pool_size, new_pool_size;
+	u64 old_mtu, new_mtu;
+
+	if (!adapter->tx_pool)
+		return false;
+
+	old_num_pools = adapter->num_active_tx_pools;
+	new_num_pools = adapter->num_active_tx_scrqs;
+	old_pool_size = adapter->prev_tx_pool_size;
+	new_pool_size = adapter->req_tx_entries_per_subcrq;
+	old_mtu = adapter->prev_mtu;
+	new_mtu = adapter->req_mtu;
+
+	/* Require MTU to be exactly same to reuse pools for now */
+	if (old_mtu != new_mtu)
+		return false;
+
+	if (old_num_pools == new_num_pools && old_pool_size == new_pool_size)
+		return true;
+
+	if (old_num_pools < adapter->min_tx_queues ||
+	    old_num_pools > adapter->max_tx_queues ||
+	    old_pool_size < adapter->min_tx_entries_per_subcrq ||
+	    old_pool_size > adapter->max_tx_entries_per_subcrq)
+		return false;
+
+	return true;
+}
+
+/**
+ * init_tx_pools(): Initialize the set of transmit pools in the adapter.
+ * @netdev: net device associated with the vnic interface
+ *
+ * Initialize the set of transmit pools in the ibmvnic adapter associated
+ * with the net_device @netdev. If possible, reuse the existing tx pools.
+ * Otherwise free any existing pools and  allocate a new set of pools
+ * before initializing them.
+ *
+ * Return: 0 on success and negative value on error.
+ */
 static int init_tx_pools(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
@@ -900,7 +908,21 @@ static int init_tx_pools(struct net_device *netdev)
 	int num_pools;
 	u64 pool_size;		/* # of buffers in pool */
 	u64 buff_size;
-	int i, rc;
+	int i, j, rc;
+
+	num_pools = adapter->req_tx_queues;
+
+	/* We must notify the VIOS about the LTB on all resets - but we only
+	 * need to alloc/populate pools if either the number of buffers or
+	 * size of each buffer in the pool has changed.
+	 */
+	if (reuse_tx_pools(adapter)) {
+		netdev_dbg(netdev, "Reusing tx pools\n");
+		goto update_ltb;
+	}
+
+	/* Allocate/populate the pools. */
+	release_tx_pools(adapter);
 
 	pool_size = adapter->req_tx_entries_per_subcrq;
 	num_pools = adapter->num_active_tx_scrqs;
@@ -925,6 +947,7 @@ static int init_tx_pools(struct net_device *netdev)
 	 * allocation, release_tx_pools() will know how many to look for.
 	 */
 	adapter->num_active_tx_pools = num_pools;
+
 	buff_size = adapter->req_mtu + VLAN_HLEN;
 	buff_size = ALIGN(buff_size, L1_CACHE_BYTES);
 
@@ -934,21 +957,73 @@ static int init_tx_pools(struct net_device *netdev)
 
 		rc = init_one_tx_pool(netdev, &adapter->tx_pool[i],
 				      pool_size, buff_size);
-		if (rc) {
-			release_tx_pools(adapter);
-			return rc;
-		}
+		if (rc)
+			goto out_release;
 
 		rc = init_one_tx_pool(netdev, &adapter->tso_pool[i],
 				      IBMVNIC_TSO_BUFS,
 				      IBMVNIC_TSO_BUF_SZ);
-		if (rc) {
-			release_tx_pools(adapter);
-			return rc;
-		}
+		if (rc)
+			goto out_release;
+	}
+
+	adapter->prev_tx_pool_size = pool_size;
+	adapter->prev_mtu = adapter->req_mtu;
+
+update_ltb:
+	/* NOTE: All tx_pools have the same number of buffers (which is
+	 *       same as pool_size). All tso_pools have IBMVNIC_TSO_BUFS
+	 *       buffers (see calls init_one_tx_pool() for these).
+	 *       For consistency, we use tx_pool->num_buffers and
+	 *       tso_pool->num_buffers below.
+	 */
+	rc = -1;
+	for (i = 0; i < num_pools; i++) {
+		struct ibmvnic_tx_pool *tso_pool;
+		struct ibmvnic_tx_pool *tx_pool;
+		u32 ltb_size;
+
+		tx_pool = &adapter->tx_pool[i];
+		ltb_size = tx_pool->num_buffers * tx_pool->buf_size;
+		if (alloc_long_term_buff(adapter, &tx_pool->long_term_buff,
+					 ltb_size))
+			goto out;
+
+		dev_dbg(dev, "Updated LTB for tx pool %d [%p, %d, %d]\n",
+			i, tx_pool->long_term_buff.buff,
+			tx_pool->num_buffers, tx_pool->buf_size);
+
+		tx_pool->consumer_index = 0;
+		tx_pool->producer_index = 0;
+
+		for (j = 0; j < tx_pool->num_buffers; j++)
+			tx_pool->free_map[j] = j;
+
+		tso_pool = &adapter->tso_pool[i];
+		ltb_size = tso_pool->num_buffers * tso_pool->buf_size;
+		if (alloc_long_term_buff(adapter, &tso_pool->long_term_buff,
+					 ltb_size))
+			goto out;
+
+		dev_dbg(dev, "Updated LTB for tso pool %d [%p, %d, %d]\n",
+			i, tso_pool->long_term_buff.buff,
+			tso_pool->num_buffers, tso_pool->buf_size);
+
+		tso_pool->consumer_index = 0;
+		tso_pool->producer_index = 0;
+
+		for (j = 0; j < tso_pool->num_buffers; j++)
+			tso_pool->free_map[j] = j;
 	}
 
 	return 0;
+out_release:
+	release_tx_pools(adapter);
+out:
+	/* We failed to allocate one or more LTBs or map them on the VIOS.
+	 * Hold onto the pools and any LTBs that we did allocate/map.
+	 */
+	return rc;
 }
 
 static void ibmvnic_napi_enable(struct ibmvnic_adapter *adapter)
@@ -1139,8 +1214,6 @@ static void release_resources(struct ibmvnic_adapter *adapter)
 {
 	release_vpd_data(adapter);
 
-	release_tx_pools(adapter);
-
 	release_napi(adapter);
 	release_login_buffer(adapter);
 	release_login_rsp_buffer(adapter);
@@ -1413,6 +1486,7 @@ static int ibmvnic_open(struct net_device *netdev)
 			netdev_err(netdev, "failed to initialize resources\n");
 			release_resources(adapter);
 			release_rx_pools(adapter);
+			release_tx_pools(adapter);
 			goto out;
 		}
 	}
@@ -1541,8 +1615,6 @@ static void ibmvnic_cleanup(struct net_device *netdev)
 
 	ibmvnic_napi_disable(adapter);
 	ibmvnic_disable_irqs(adapter);
-
-	clean_tx_pools(adapter);
 }
 
 static int __ibmvnic_close(struct net_device *netdev)
@@ -1577,6 +1649,7 @@ static int ibmvnic_close(struct net_device *netdev)
 	rc = __ibmvnic_close(netdev);
 	ibmvnic_cleanup(netdev);
 	clean_rx_pools(adapter);
+	clean_tx_pools(adapter);
 
 	return rc;
 }
@@ -2153,9 +2226,9 @@ static const char *reset_reason_to_string(enum ibmvnic_reset_reason reason)
 static int do_reset(struct ibmvnic_adapter *adapter,
 		    struct ibmvnic_rwi *rwi, u32 reset_state)
 {
+	struct net_device *netdev = adapter->netdev;
 	u64 old_num_rx_queues, old_num_tx_queues;
 	u64 old_num_rx_slots, old_num_tx_slots;
-	struct net_device *netdev = adapter->netdev;
 	int rc;
 
 	netdev_dbg(adapter->netdev,
@@ -2305,7 +2378,6 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 		    !adapter->rx_pool ||
 		    !adapter->tso_pool ||
 		    !adapter->tx_pool) {
-			release_tx_pools(adapter);
 			release_napi(adapter);
 			release_vpd_data(adapter);
 
@@ -2314,9 +2386,10 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 				goto out;
 
 		} else {
-			rc = reset_tx_pools(adapter);
+			rc = init_tx_pools(netdev);
 			if (rc) {
-				netdev_dbg(adapter->netdev, "reset tx pools failed (%d)\n",
+				netdev_dbg(netdev,
+					   "init tx pools failed (%d)\n",
 					   rc);
 				goto out;
 			}
@@ -5661,6 +5734,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
 	init_completion(&adapter->stats_done);
 	clear_bit(0, &adapter->resetting);
 	adapter->prev_rx_buf_sz = 0;
+	adapter->prev_mtu = 0;
 
 	init_success = false;
 	do {
@@ -5762,6 +5836,7 @@ static void ibmvnic_remove(struct vio_dev *dev)
 
 	release_resources(adapter);
 	release_rx_pools(adapter);
+	release_tx_pools(adapter);
 	release_sub_crqs(adapter, 1);
 	release_crq_queue(adapter);
 
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index b73a1b812368..b8e42f67d897 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -967,6 +967,7 @@ struct ibmvnic_adapter {
 	u64 min_mtu;
 	u64 max_mtu;
 	u64 req_mtu;
+	u64 prev_mtu;
 	u64 max_multicast_filters;
 	u64 vlan_header_insertion;
 	u64 rx_vlan_header_insertion;
@@ -988,6 +989,7 @@ struct ibmvnic_adapter {
 	u32 num_active_tx_pools;
 
 	u32 prev_rx_pool_size;
+	u32 prev_tx_pool_size;
 	u32 cur_rx_buf_sz;
 	u32 prev_rx_buf_sz;
 
-- 
2.26.2

Re: [PATCH net-next v2 0/9] ibmvnic: Reuse ltb, rx, tx pools

[David Miller]

net-next is closed, please resubmit when it opens back up.

Thank you.