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authorElena Reshetova <elena.reshetova@intel.com>2017-10-20 10:23:39 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-22 04:22:38 +0300
commit17ac99b2b8d08ed40f4525491d6eff330329a6d2 (patch)
tree1610c1f3c19209b8eaaaccfe4b7ecc40543e4db4
parent0068895ff845c38e9e2b65c002c53c623379e436 (diff)
downloadlinux-17ac99b2b8d08ed40f4525491d6eff330329a6d2.tar.xz
drivers, net, mlx4: convert mlx4_srq.refcount from atomic_t to refcount_t
atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable mlx4_srq.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ethernet/mellanox/mlx4/srq.c8
-rw-r--r--include/linux/mlx4/device.h2
2 files changed, 5 insertions, 5 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx4/srq.c b/drivers/net/ethernet/mellanox/mlx4/srq.c
index bedf52126824..cbe4d9746ddf 100644
--- a/drivers/net/ethernet/mellanox/mlx4/srq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/srq.c
@@ -49,7 +49,7 @@ void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type)
srq = radix_tree_lookup(&srq_table->tree, srqn & (dev->caps.num_srqs - 1));
rcu_read_unlock();
if (srq)
- atomic_inc(&srq->refcount);
+ refcount_inc(&srq->refcount);
else {
mlx4_warn(dev, "Async event for bogus SRQ %08x\n", srqn);
return;
@@ -57,7 +57,7 @@ void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type)
srq->event(srq, event_type);
- if (atomic_dec_and_test(&srq->refcount))
+ if (refcount_dec_and_test(&srq->refcount))
complete(&srq->free);
}
@@ -203,7 +203,7 @@ int mlx4_srq_alloc(struct mlx4_dev *dev, u32 pdn, u32 cqn, u16 xrcd,
if (err)
goto err_radix;
- atomic_set(&srq->refcount, 1);
+ refcount_set(&srq->refcount, 1);
init_completion(&srq->free);
return 0;
@@ -232,7 +232,7 @@ void mlx4_srq_free(struct mlx4_dev *dev, struct mlx4_srq *srq)
radix_tree_delete(&srq_table->tree, srq->srqn);
spin_unlock_irq(&srq_table->lock);
- if (atomic_dec_and_test(&srq->refcount))
+ if (refcount_dec_and_test(&srq->refcount))
complete(&srq->free);
wait_for_completion(&srq->free);
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index b8e19c4d6caa..a9b5fed8f7c6 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -781,7 +781,7 @@ struct mlx4_srq {
int max_gs;
int wqe_shift;
- atomic_t refcount;
+ refcount_t refcount;
struct completion free;
};