Subject: [net V2 14/15] net/mlx5e: kTLS, Avoid kzalloc(GFP_KERNEL) under spinlock

From: [email-masked]
Date: Mon, 21 Sep 2020 17:31:00 -0700

From: Saeed Mahameed <[email-masked]>

The spinlock only needed when accessing the channel's icosq, grab the lock
after the buf allocation in resync_post_get_progress_params() to avoid
kzalloc(GFP_KERNEL) in atomic context.

Fixes: 0419d8c9d8f8 ("net/mlx5e: kTLS, Add kTLS RX resync support")
Reported-by: YueHaibing <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
Reviewed-by: Tariq Toukan <[email-masked]>
---
 .../mellanox/mlx5/core/en_accel/ktls_rx.c     | 25 ++++++++-----------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c
index e85411bd1fed..6bbfcf18107d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_rx.c
@@ -234,7 +234,7 @@ mlx5e_get_ktls_rx_priv_ctx(struct tls_context *tls_ctx)
 
 /* Re-sync */
 /* Runs in work context */
-static struct mlx5_wqe_ctrl_seg *
+static int
 resync_post_get_progress_params(struct mlx5e_icosq *sq,
 				struct mlx5e_ktls_offload_context_rx *priv_rx)
 {
@@ -264,7 +264,11 @@ resync_post_get_progress_params(struct mlx5e_icosq *sq,
 	buf->priv_rx = priv_rx;
 
 	BUILD_BUG_ON(MLX5E_KTLS_GET_PROGRESS_WQEBBS != 1);
+
+	spin_lock(&sq->channel->async_icosq_lock);
+
 	if (unlikely(!mlx5e_wqc_has_room_for(&sq->wq, sq->cc, sq->pc, 1))) {
+		spin_unlock(&sq->channel->async_icosq_lock);
 		err = -ENOSPC;
 		goto err_dma_unmap;
 	}
@@ -294,8 +298,10 @@ resync_post_get_progress_params(struct mlx5e_icosq *sq,
 	};
 	icosq_fill_wi(sq, pi, &wi);
 	sq->pc++;
+	mlx5e_notify_hw(&sq->wq, sq->pc, sq->uar_map, cseg);
+	spin_unlock(&sq->channel->async_icosq_lock);
 
-	return cseg;
+	return 0;
 
 err_dma_unmap:
 	dma_unmap_single(pdev, buf->dma_addr, PROGRESS_PARAMS_PADDED_SIZE, DMA_FROM_DEVICE);
@@ -303,7 +309,7 @@ resync_post_get_progress_params(struct mlx5e_icosq *sq,
 	kfree(buf);
 err_out:
 	priv_rx->stats->tls_resync_req_skip++;
-	return ERR_PTR(err);
+	return err;
 }
 
 /* Function is called with elevated refcount.
@@ -313,10 +319,8 @@ static void resync_handle_work(struct work_struct *work)
 {
 	struct mlx5e_ktls_offload_context_rx *priv_rx;
 	struct mlx5e_ktls_rx_resync_ctx *resync;
-	struct mlx5_wqe_ctrl_seg *cseg;
 	struct mlx5e_channel *c;
 	struct mlx5e_icosq *sq;
-	struct mlx5_wq_cyc *wq;
 
 	resync = container_of(work, struct mlx5e_ktls_rx_resync_ctx, work);
 	priv_rx = container_of(resync, struct mlx5e_ktls_offload_context_rx, resync);
@@ -328,18 +332,9 @@ static void resync_handle_work(struct work_struct *work)
 
 	c = resync->priv->channels.c[priv_rx->rxq];
 	sq = &c->async_icosq;
-	wq = &sq->wq;
 
-	spin_lock(&c->async_icosq_lock);
-
-	cseg = resync_post_get_progress_params(sq, priv_rx);
-	if (IS_ERR(cseg)) {
+	if (resync_post_get_progress_params(sq, priv_rx))
 		refcount_dec(&resync->refcnt);
-		goto unlock;
-	}
-	mlx5e_notify_hw(wq, sq->pc, sq->uar_map, cseg);
-unlock:
-	spin_unlock(&c->async_icosq_lock);
 }
 
 static void resync_init(struct mlx5e_ktls_rx_resync_ctx *resync,
-- 
2.26.2