FAILED: patch "[PATCH] net: mana: Reserve extra CQ slot for the fence completion CQE" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 80dd7e754b3aa9637a0758ad93fa209f9650ec48
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091623-upstairs-protrude-105f@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 80dd7e754b3aa9637a0758ad93fa209f9650ec48 Mon Sep 17 00:00:00 2001
From: Sahil Chandna <[email protected]>
Date: Tue, 1 Sep 2026 07:17:58 -0500
Subject: [PATCH] net: mana: Reserve extra CQ slot for the fence completion CQE

The RX completion queue is sized to hold exactly one CQE per posted RX WQE. MANA_FENCE_RQ makes hardware post an additional CQE_RX_OBJECT_FENCE after the packet CQEs. The current sizing reserves no extra slot for it and in rare cases, CQ has no guaranteed slot for the fence CQE when it is full of packet CQEs. This can lead to dropping the fence completion while the driver waits holding RTNL lock throughout the timeout duration. Reserve one extra CQE slot for CQE_RX_OBJECT_FENCE. mana_gd_alloc_memory() requires queue_size to be a power-of-two and at least MANA_PAGE_SIZE; the reservation pushes cq_size past a power-of-two, so round up the CQ size in mana_create_rxq().

index 7a1ac853e3ab..45a7520491a6 100644
@@ -2986,6 +2986,10 @@ static int mana_alloc_rx_wqe(struct mana_port_context *apc,
 		*cq_size += COMP_ENTRY_SIZE;
 	}
 
+	/* Reserve an extra slot for Fence completion
+	 * event (CQE_RX_OBJECT_FENCE) in case RX CQ is full.
+	 */
+	*cq_size += COMP_ENTRY_SIZE;
 	return 0;
 }
 

@@ -3080,7 +3084,7 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 		goto out;
 
 	rq_size = MANA_PAGE_ALIGN(rq_size);
-	cq_size = MANA_PAGE_ALIGN(cq_size);
+	cq_size = MANA_PAGE_ALIGN(roundup_pow_of_two(cq_size));
 
 	/* Create RQ */
 	memset(&spec, 0, sizeof(spec));

From: Sahil Chandna <[email protected]>

[ Upstream commit 80dd7e754b3aa9637a0758ad93fa209f9650ec48 ]

The RX completion queue is sized to hold exactly one CQE per posted RX WQE. MANA_FENCE_RQ makes hardware post an additional CQE_RX_OBJECT_FENCE after the packet CQEs. The current sizing reserves no extra slot for it and in rare cases, CQ has no guaranteed slot for the fence CQE when it is full of packet CQEs. This can lead to dropping the fence completion while the driver waits holding RTNL lock throughout the timeout duration. Reserve one extra CQE slot for CQE_RX_OBJECT_FENCE. mana_gd_alloc_memory() requires queue_size to be a power-of-two and at least MANA_PAGE_SIZE; the reservation pushes cq_size past a power-of-two, so round up the CQ size in mana_create_rxq().

---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

index 4afcb202e3509..2d1e5b83a0769 100644
@@ -1662,6 +1662,10 @@ static int mana_alloc_rx_wqe(struct mana_port_context *apc,
 		*cq_size += COMP_ENTRY_SIZE;
 	}
 
+	/* Reserve an extra slot for Fence completion
+	 * event (CQE_RX_OBJECT_FENCE) in case RX CQ is full.
+	 */
+	*cq_size += COMP_ENTRY_SIZE;
 	return 0;
 }
 

@@ -1715,7 +1719,7 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 		goto out;
 
 	rq_size = PAGE_ALIGN(rq_size);
-	cq_size = PAGE_ALIGN(cq_size);
+	cq_size = PAGE_ALIGN(roundup_pow_of_two(cq_size));
 
 	/* Create RQ */
 	memset(&spec, 0, sizeof(spec));

2.53.0