[bpf-next V1-RFC PATCH 05/14] xdp/qede: setup xdp_rxq_info and intro xdp_rxq_info_is_reg

[Jesper Dangaard Brouer <brouer@redhat.com>]

The driver code qede_free_fp_array() depend on kfree() can be called
with a NULL pointer. This stems from the qede_alloc_fp_array()
function which either (kz)alloc memory for fp->txq or fp->rxq.
This also simplifies error handling code in case of memory allocation
failures, but xdp_rxq_info_unreg need to know the difference.

Introduce xdp_rxq_info_is_reg() to handle if a memory allocation fails
and detect this is the failure path by seeing that xdp_rxq_info was
not registred yet, which first happens after successful alloaction in
qede_init_fp().

Driver hook points for xdp_rxq_info:
 * init+reg: qede_init_fp
 * unreg   : qede_free_fp_array

Tested on actual hardware with samples/bpf program.

Cc: everest-linux-l2@cavium.com
Cc: Ariel Elior <Ariel.Elior@cavium.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
---
 drivers/net/ethernet/qlogic/qede/qede.h      |    2 ++
 drivers/net/ethernet/qlogic/qede/qede_fp.c   |    1 +
 drivers/net/ethernet/qlogic/qede/qede_main.c |   12 ++++++++++++
 include/net/xdp.h                            |    1 +
 net/core/xdp.c                               |   11 +++++++++++
 5 files changed, 27 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qede/qede.h b/drivers/net/ethernet/qlogic/qede/qede.h
index a3a70ade411f..62f47736511b 100644
--- a/drivers/net/ethernet/qlogic/qede/qede.h
+++ b/drivers/net/ethernet/qlogic/qede/qede.h
@@ -40,6 +40,7 @@
 #include <linux/kernel.h>
 #include <linux/mutex.h>
 #include <linux/bpf.h>
+#include <net/xdp.h>
 #include <linux/qed/qede_rdma.h>
 #include <linux/io.h>
 #ifdef CONFIG_RFS_ACCEL
@@ -345,6 +346,7 @@ struct qede_rx_queue {
 	u64 xdp_no_pass;
 
 	void *handle;
+	struct xdp_rxq_info xdp_rxq;
 };
 
 union db_prod {
diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c
index 48ec4c56cddf..dafc079ab6b9 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_fp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c
@@ -1006,6 +1006,7 @@ static bool qede_rx_xdp(struct qede_dev *edev,
 	xdp.data = xdp.data_hard_start + *data_offset;
 	xdp_set_data_meta_invalid(&xdp);
 	xdp.data_end = xdp.data + *len;
+	xdp.rxq = &rxq->xdp_rxq;
 
 	/* Queues always have a full reset currently, so for the time
 	 * being until there's atomic program replace just mark read
diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c
index 57332b3e5e64..a7264fdf4112 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_main.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
@@ -762,6 +762,12 @@ static void qede_free_fp_array(struct qede_dev *edev)
 			fp = &edev->fp_array[i];
 
 			kfree(fp->sb_info);
+			/* Handle mem alloc failure case where qede_init_fp
+			 * didn't register xdp_rxq_info yet.
+			 * Implicit only (fp->type & QEDE_FASTPATH_RX)
+			 */
+			if (fp->rxq && xdp_rxq_info_is_reg(&fp->rxq->xdp_rxq))
+				xdp_rxq_info_unreg(&fp->rxq->xdp_rxq);
 			kfree(fp->rxq);
 			kfree(fp->xdp_tx);
 			kfree(fp->txq);
@@ -1498,6 +1504,12 @@ static void qede_init_fp(struct qede_dev *edev)
 			else
 				fp->rxq->data_direction = DMA_FROM_DEVICE;
 			fp->rxq->dev = &edev->pdev->dev;
+
+			/* XDP RX-queue info */
+			xdp_rxq_info_init(&fp->rxq->xdp_rxq);
+			fp->rxq->xdp_rxq.dev = edev->ndev;
+			fp->rxq->xdp_rxq.queue_index = fp->rxq->rxq_id;
+			xdp_rxq_info_reg(&fp->rxq->xdp_rxq);
 		}
 
 		if (fp->type & QEDE_FASTPATH_TX) {
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 5be560d943e1..106ec8ed4db5 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -42,6 +42,7 @@ struct xdp_rxq_info {
 void xdp_rxq_info_init(struct xdp_rxq_info *xdp_rxq);
 void xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq);
 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
+bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
 
 /**
  * DOC: XDP RX-queue type
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 2a111f5987f6..f0203b8fc04c 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -44,3 +44,14 @@ void xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq)
 	xdp_rxq->reg_state = REG_STATE_REGISTRED;
 }
 EXPORT_SYMBOL_GPL(xdp_rxq_info_reg);
+
+bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq)
+{
+	if (!xdp_rxq) {
+		WARN(1, "API violation, xdp_rxq is NULL");
+		return false;
+	}
+
+	return (xdp_rxq->reg_state == REG_STATE_REGISTRED);
+}
+EXPORT_SYMBOL_GPL(xdp_rxq_info_is_reg);