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author | Jason Gunthorpe <jgg@mellanox.com> | 2020-03-10 11:25:31 +0200 |
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committer | Jason Gunthorpe <jgg@mellanox.com> | 2020-03-17 17:05:51 -0300 |
commit | e8dc4e885c459343970b25acd9320fe9ee5492e7 (patch) | |
tree | b288f5ba4ab604be52dd2744cbd889f47fd43d56 /drivers/infiniband/core | |
parent | 9e57a9aa694cfc28f9549d2ce587309fdac15bfb (diff) | |
download | linux-e8dc4e885c459343970b25acd9320fe9ee5492e7.tar.gz linux-e8dc4e885c459343970b25acd9320fe9ee5492e7.tar.bz2 linux-e8dc4e885c459343970b25acd9320fe9ee5492e7.zip |
RDMA/cm: Fix ordering of xa_alloc_cyclic() in ib_create_cm_id()
xa_alloc_cyclic() is a SMP release to be paired with some later acquire
during xa_load() as part of cm_acquire_id().
As such, xa_alloc_cyclic() must be done after the cm_id is fully
initialized, in particular, it absolutely must be after the
refcount_set(), otherwise the refcount_inc() in cm_acquire_id() may not
see the set.
As there are several cases where a reader will be able to use the
id.local_id after cm_acquire_id in the IB_CM_IDLE state there needs to be
an unfortunate split into a NULL allocate and a finalizing xa_store.
Fixes: a977049dacde ("[PATCH] IB: Add the kernel CM implementation")
Link: https://lore.kernel.org/r/20200310092545.251365-2-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'drivers/infiniband/core')
-rw-r--r-- | drivers/infiniband/core/cm.c | 27 |
1 files changed, 11 insertions, 16 deletions
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index 21ede1c08eea..db627fa3cd39 100644 --- a/drivers/infiniband/core/cm.c +++ b/drivers/infiniband/core/cm.c @@ -571,18 +571,6 @@ static int cm_init_av_by_path(struct sa_path_rec *path, return 0; } -static int cm_alloc_id(struct cm_id_private *cm_id_priv) -{ - int err; - u32 id; - - err = xa_alloc_cyclic_irq(&cm.local_id_table, &id, cm_id_priv, - xa_limit_32b, &cm.local_id_next, GFP_KERNEL); - - cm_id_priv->id.local_id = (__force __be32)id ^ cm.random_id_operand; - return err; -} - static u32 cm_local_id(__be32 local_id) { return (__force u32) (local_id ^ cm.random_id_operand); @@ -824,6 +812,7 @@ struct ib_cm_id *ib_create_cm_id(struct ib_device *device, void *context) { struct cm_id_private *cm_id_priv; + u32 id; int ret; cm_id_priv = kzalloc(sizeof *cm_id_priv, GFP_KERNEL); @@ -835,9 +824,6 @@ struct ib_cm_id *ib_create_cm_id(struct ib_device *device, cm_id_priv->id.cm_handler = cm_handler; cm_id_priv->id.context = context; cm_id_priv->id.remote_cm_qpn = 1; - ret = cm_alloc_id(cm_id_priv); - if (ret) - goto error; spin_lock_init(&cm_id_priv->lock); init_completion(&cm_id_priv->comp); @@ -846,11 +832,20 @@ struct ib_cm_id *ib_create_cm_id(struct ib_device *device, INIT_LIST_HEAD(&cm_id_priv->altr_list); atomic_set(&cm_id_priv->work_count, -1); refcount_set(&cm_id_priv->refcount, 1); + + ret = xa_alloc_cyclic_irq(&cm.local_id_table, &id, NULL, xa_limit_32b, + &cm.local_id_next, GFP_KERNEL); + if (ret) + goto error; + cm_id_priv->id.local_id = (__force __be32)id ^ cm.random_id_operand; + xa_store_irq(&cm.local_id_table, cm_local_id(cm_id_priv->id.local_id), + cm_id_priv, GFP_KERNEL); + return &cm_id_priv->id; error: kfree(cm_id_priv); - return ERR_PTR(-ENOMEM); + return ERR_PTR(ret); } EXPORT_SYMBOL(ib_create_cm_id); |