linux-kernel - [PATCH 2/2] ntb: ntb_transport: Replace GFP_ATOMIC with GFP_KERNEL in ntb_transport_create

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Date:   Tue, 10 Apr 2018 21:17:54 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     jdmason@...zu.us, dave.jiang@...el.com, Allen.Hubbe@....com
Cc:     linux-ntb@...glegroups.com, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH 2/2] ntb: ntb_transport: Replace GFP_ATOMIC with GFP_KERNEL in ntb_transport_create_queue

ntb_transport_create_queue() is never called in atomic context.

ntb_transport_create_queue() is only called by ntb_netdev_probe(),
which is set as ".probe" in struct ntb_transport_client.

Despite never getting called from atomic context,
ntb_transport_create_queue() calls kzalloc_node() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/ntb/ntb_transport.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index f58d8e3..2c0c8bc 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1825,7 +1825,7 @@ struct ntb_transport_qp *
 		qp->rx_dma_chan ? "DMA" : "CPU");

 	for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
-		entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
+		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
 		if (!entry)
 			goto err1;

@@ -1836,7 +1836,7 @@ struct ntb_transport_qp *
 	qp->rx_alloc_entry = NTB_QP_DEF_NUM_ENTRIES;

 	for (i = 0; i < qp->tx_max_entry; i++) {
-		entry = kzalloc_node(sizeof(*entry), GFP_ATOMIC, node);
+		entry = kzalloc_node(sizeof(*entry), GFP_KERNEL, node);
 		if (!entry)
 			goto err2;

-- 
1.9.1