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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sagi Grimberg <sagi@grimberg.me>,
        Saeed Mahameed <saeedm@mellanox.com>
Subject: [PATCH 4.14 41/71] net/mlx5: Fix get vector affinity helper function
Date:   Mon, 29 Jan 2018 13:57:09 +0100
Message-Id: <20180129123830.004669484@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Saeed Mahameed <saeedm@mellanox.com>


[ Upstream commit 05e0cc84e00c54fb152d1f4b86bc211823a83d0c ]

mlx5_get_vector_affinity used to call pci_irq_get_affinity and after
reverting the patch that sets the device affinity via PCI_IRQ_AFFINITY
API, calling pci_irq_get_affinity becomes useless and it breaks RDMA
mlx5 users.  To fix this, this patch provides an alternative way to
retrieve IRQ vector affinity using legacy IRQ API, following
smp_affinity read procfs implementation.

Fixes: 231243c82793 ("Revert mlx5: move affinity hints assignments to generic code")
Fixes: a435393acafb ("mlx5: move affinity hints assignments to generic code")
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/mlx5/driver.h |   19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -36,6 +36,7 @@
 #include <linux/kernel.h>
 #include <linux/completion.h>
 #include <linux/pci.h>
+#include <linux/irq.h>
 #include <linux/spinlock_types.h>
 #include <linux/semaphore.h>
 #include <linux/slab.h>
@@ -1194,7 +1195,23 @@ enum {
 static inline const struct cpumask *
 mlx5_get_vector_affinity(struct mlx5_core_dev *dev, int vector)
 {
-	return pci_irq_get_affinity(dev->pdev, MLX5_EQ_VEC_COMP_BASE + vector);
+	const struct cpumask *mask;
+	struct irq_desc *desc;
+	unsigned int irq;
+	int eqn;
+	int err;
+
+	err = mlx5_vector2eqn(dev, vector, &eqn, &irq);
+	if (err)
+		return NULL;
+
+	desc = irq_to_desc(irq);
+#ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
+	mask = irq_data_get_effective_affinity_mask(&desc->irq_data);
+#else
+	mask = desc->irq_common_data.affinity;
+#endif
+	return mask;
 }
 
 #endif /* MLX5_DRIVER_H */