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IB/qib: Correct reference counting in debugfs qp_stats 

This particular reference count is not needed with the rcu protection,
and the current code leaks a reference count, causing a hang in
qib_qp_destroy().

Cc: <stable@vger.kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Mike Marciniszyn 2014-09-19 08:32:19 -04:00 committed by Roland Dreier
parent f5c4984e06
commit 85cbb7c728
2 changed files with 2 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/infiniband/hw/qib/qib_debugfs.c
View File

@ -193,6 +193,7 @@ static void *_qp_stats_seq_start(struct seq_file *s, loff_t *pos)
struct qib_qp_iter *iter;
loff_t n = *pos;
rcu_read_lock();
iter = qib_qp_iter_init(s->private);
if (!iter)
return NULL;
@ -224,7 +225,7 @@ static void *_qp_stats_seq_next(struct seq_file *s, void *iter_ptr,
static void _qp_stats_seq_stop(struct seq_file *s, void *iter_ptr)
{
/* nothing for now */
rcu_read_unlock();
}
static int _qp_stats_seq_show(struct seq_file *s, void *iter_ptr)

8
drivers/infiniband/hw/qib/qib_qp.c
View File

@ -1325,7 +1325,6 @@ int qib_qp_iter_next(struct qib_qp_iter *iter)
struct qib_qp *pqp = iter->qp;
struct qib_qp *qp;
rcu_read_lock();
for (; n < dev->qp_table_size; n++) {
if (pqp)
qp = rcu_dereference(pqp->next);
@ -1333,18 +1332,11 @@ int qib_qp_iter_next(struct qib_qp_iter *iter)
qp = rcu_dereference(dev->qp_table[n]);
pqp = qp;
if (qp) {
if (iter->qp)
atomic_dec(&iter->qp->refcount);
atomic_inc(&qp->refcount);
rcu_read_unlock();
iter->qp = qp;
iter->n = n;
return 0;
}
}
rcu_read_unlock();
if (iter->qp)
atomic_dec(&iter->qp->refcount);
return ret;
}