From: "Matthew Wilcox (Oracle)" <wi...@infradead.org>

This XArray appears to be modifiable from interrupt context, so we have
to be a little more careful with the locking.  However, the lookup can
be done without the spinlock held.  I cannot determine whether
mlx4_qp_alloc() is allowed to sleep, so I've retained the GFP_ATOMIC
there, but it could be turned into GFP_KERNEL if the callers can
tolerate it sleeping.

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 drivers/net/ethernet/mellanox/mlx4/mlx4.h |  3 +-
 drivers/net/ethernet/mellanox/mlx4/qp.c   | 37 ++++++-----------------
 include/linux/mlx4/device.h               |  4 +--
 include/linux/mlx4/qp.h                   |  2 +-
 4 files changed, 14 insertions(+), 32 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h 
b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
index b6fe22bee9f4..aaece8480da7 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
@@ -38,7 +38,7 @@
 #define MLX4_H
 
 #include <linux/mutex.h>
-#include <linux/radix-tree.h>
+#include <linux/xarray.h>
 #include <linux/rbtree.h>
 #include <linux/timer.h>
 #include <linux/semaphore.h>
@@ -716,7 +716,6 @@ struct mlx4_qp_table {
        u32                     zones_uids[MLX4_QP_TABLE_ZONE_NUM];
        u32                     rdmarc_base;
        int                     rdmarc_shift;
-       spinlock_t              lock;
        struct mlx4_icm_table   qp_table;
        struct mlx4_icm_table   auxc_table;
        struct mlx4_icm_table   altc_table;
diff --git a/drivers/net/ethernet/mellanox/mlx4/qp.c 
b/drivers/net/ethernet/mellanox/mlx4/qp.c
index 427e7a31862c..4659ecec12c1 100644
--- a/drivers/net/ethernet/mellanox/mlx4/qp.c
+++ b/drivers/net/ethernet/mellanox/mlx4/qp.c
@@ -48,16 +48,13 @@
 
 void mlx4_qp_event(struct mlx4_dev *dev, u32 qpn, int event_type)
 {
-       struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table;
        struct mlx4_qp *qp;
 
-       spin_lock(&qp_table->lock);
-
+       xa_lock(&dev->qp_table);
        qp = __mlx4_qp_lookup(dev, qpn);
        if (qp)
                refcount_inc(&qp->refcount);
-
-       spin_unlock(&qp_table->lock);
+       xa_unlock(&dev->qp_table);
 
        if (!qp) {
                mlx4_dbg(dev, "Async event for none existent QP %08x\n", qpn);
@@ -390,21 +387,11 @@ static void mlx4_qp_free_icm(struct mlx4_dev *dev, int 
qpn)
 
 struct mlx4_qp *mlx4_qp_lookup(struct mlx4_dev *dev, u32 qpn)
 {
-       struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table;
-       struct mlx4_qp *qp;
-
-       spin_lock_irq(&qp_table->lock);
-
-       qp = __mlx4_qp_lookup(dev, qpn);
-
-       spin_unlock_irq(&qp_table->lock);
-       return qp;
+       return __mlx4_qp_lookup(dev, qpn);
 }
 
 int mlx4_qp_alloc(struct mlx4_dev *dev, int qpn, struct mlx4_qp *qp)
 {
-       struct mlx4_priv *priv = mlx4_priv(dev);
-       struct mlx4_qp_table *qp_table = &priv->qp_table;
        int err;
 
        if (!qpn)
@@ -416,10 +403,9 @@ int mlx4_qp_alloc(struct mlx4_dev *dev, int qpn, struct 
mlx4_qp *qp)
        if (err)
                return err;
 
-       spin_lock_irq(&qp_table->lock);
-       err = radix_tree_insert(&dev->qp_table_tree, qp->qpn &
-                               (dev->caps.num_qps - 1), qp);
-       spin_unlock_irq(&qp_table->lock);
+       err = xa_err(xa_store_irq(&dev->qp_table,
+                               qp->qpn & (dev->caps.num_qps - 1),
+                               qp, GFP_ATOMIC));
        if (err)
                goto err_icm;
 
@@ -512,12 +498,11 @@ EXPORT_SYMBOL_GPL(mlx4_update_qp);
 
 void mlx4_qp_remove(struct mlx4_dev *dev, struct mlx4_qp *qp)
 {
-       struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table;
        unsigned long flags;
 
-       spin_lock_irqsave(&qp_table->lock, flags);
-       radix_tree_delete(&dev->qp_table_tree, qp->qpn & (dev->caps.num_qps - 
1));
-       spin_unlock_irqrestore(&qp_table->lock, flags);
+       xa_lock_irqsave(&dev->qp_table, flags);
+       __xa_erase(&dev->qp_table, qp->qpn & (dev->caps.num_qps - 1));
+       xa_unlock_irqrestore(&dev->qp_table, flags);
 }
 EXPORT_SYMBOL_GPL(mlx4_qp_remove);
 
@@ -760,7 +745,6 @@ static void mlx4_cleanup_qp_zones(struct mlx4_dev *dev)
 
 int mlx4_init_qp_table(struct mlx4_dev *dev)
 {
-       struct mlx4_qp_table *qp_table = &mlx4_priv(dev)->qp_table;
        int err;
        int reserved_from_top = 0;
        int reserved_from_bot;
@@ -770,8 +754,7 @@ int mlx4_init_qp_table(struct mlx4_dev *dev)
        u32 max_table_offset = dev->caps.dmfs_high_rate_qpn_base +
                        dev->caps.dmfs_high_rate_qpn_range;
 
-       spin_lock_init(&qp_table->lock);
-       INIT_RADIX_TREE(&dev->qp_table_tree, GFP_ATOMIC);
+       xa_init_flags(&dev->qp_table, XA_FLAGS_LOCK_IRQ);
        if (mlx4_is_slave(dev))
                return 0;
 
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 36e412c3d657..acffca7d9f00 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -36,7 +36,7 @@
 #include <linux/if_ether.h>
 #include <linux/pci.h>
 #include <linux/completion.h>
-#include <linux/radix-tree.h>
+#include <linux/xarray.h>
 #include <linux/cpu_rmap.h>
 #include <linux/crash_dump.h>
 
@@ -889,7 +889,7 @@ struct mlx4_dev {
        struct mlx4_caps        caps;
        struct mlx4_phys_caps   phys_caps;
        struct mlx4_quotas      quotas;
-       struct radix_tree_root  qp_table_tree;
+       struct xarray           qp_table;
        u8                      rev_id;
        u8                      port_random_macs;
        char                    board_id[MLX4_BOARD_ID_LEN];
diff --git a/include/linux/mlx4/qp.h b/include/linux/mlx4/qp.h
index 8e2828d48d7f..6c3ec3197a10 100644
--- a/include/linux/mlx4/qp.h
+++ b/include/linux/mlx4/qp.h
@@ -488,7 +488,7 @@ int mlx4_qp_to_ready(struct mlx4_dev *dev, struct mlx4_mtt 
*mtt,
 
 static inline struct mlx4_qp *__mlx4_qp_lookup(struct mlx4_dev *dev, u32 qpn)
 {
-       return radix_tree_lookup(&dev->qp_table_tree, qpn & (dev->caps.num_qps 
- 1));
+       return xa_load(&dev->qp_table, qpn & (dev->caps.num_qps - 1));
 }
 
 void mlx4_qp_remove(struct mlx4_dev *dev, struct mlx4_qp *qp);
-- 
2.23.0.rc1

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