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Subject[PATCH 1/1] rapidio/rio_cm: avoid GFP_KERNEL in atomic context
Date
As reported by Alexey Khoroshilov <khoroshilov@ispras.ru>
(see https://lkml.org/lkml/2016/9/9/737):
riocm_send_close() is called from rio_cm_shutdown() under
spin_lock_bh(idr_lock), but riocm_send_close() uses a GFP_KERNEL
allocation.

Fix by taking riocm_send_close() outside of spinlock protected code.

Reported-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: Alexey Khoroshilov <khoroshilov@ispras.ru>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
---
drivers/rapidio/rio_cm.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/rapidio/rio_cm.c b/drivers/rapidio/rio_cm.c
index 3226983..0e91335 100644
--- a/drivers/rapidio/rio_cm.c
+++ b/drivers/rapidio/rio_cm.c
@@ -2242,17 +2242,31 @@ static int rio_cm_shutdown(struct notifier_block *nb, unsigned long code,
{
struct rio_channel *ch;
unsigned int i;
+ LIST_HEAD(list);

riocm_debug(EXIT, ".");

+ /*
+ * If there are any channels left in connected state send
+ * close notification to the connection partner.
+ * First build a list of channels that require a closing
+ * notification because function riocm_send_close() should
+ * be called outside of spinlock protected code.
+ */
spin_lock_bh(&idr_lock);
idr_for_each_entry(&ch_idr, ch, i) {
- riocm_debug(EXIT, "close ch %d", ch->id);
- if (ch->state == RIO_CM_CONNECTED)
- riocm_send_close(ch);
+ if (ch->state == RIO_CM_CONNECTED) {
+ riocm_debug(EXIT, "close ch %d", ch->id);
+ idr_remove(&ch_idr, ch->id);
+ list_add(&ch->ch_node, &list);
+ }
}
spin_unlock_bh(&idr_lock);

+ if (!list_empty(&list))
+ list_for_each_entry(ch, &list, ch_node)
+ riocm_send_close(ch);
+
return NOTIFY_DONE;
}

--
2.9.0
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