[PATCH] libcxgbi: do not print a message when memory allocation fails

-----Original Message-----
From: Thadeu Lima de Souza Cascardo [mailto:cascardo@linux.vnet.ibm.com]

Sent: Wednesday, December 14, 2011 7:46 AM
To: linux-scsi@vger.kernel.org
Cc: netdev@vger.kernel.org; Karen Xie; michaelc@cs.wisc.edu;
davem@davemloft.net; JBottomley@parallels.com;
linux-kernel@vger.kernel.org; Thadeu Lima de Souza Cascardo
Subject: [PATCH] libcxgbi: do not print a message when memory allocation
fails

In alloc_pdu, libcxgbi tries to allocate a skb with GFP_ATOMIC, which
may potentially fail. When it happens, the current code prints a warning
message.

When the system is under IO stress, this failure may happen lots of
times and it usually scares users.

Instead of printing the warning message, the code now increases the
tx_dropped statistics for the ethernet interface wich is doing the iscsi
task.

Signed-off-by: Thadeu Lima de Souza Cascardo
[off-list ref]
---
 drivers/scsi/cxgbi/libcxgbi.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/cxgbi/libcxgbi.c

b/drivers/scsi/cxgbi/libcxgbi.c
index c10f74a..3422bc2 100644

--- a/drivers/scsi/cxgbi/libcxgbi.c
+++ b/drivers/scsi/cxgbi/libcxgbi.c

@@ -1862,8 +1862,9 @@ int cxgbi_conn_alloc_pdu(struct iscsi_task *task,

u8 opcode)
 
 	tdata->skb = alloc_skb(cdev->skb_tx_rsvd + headroom,
GFP_ATOMIC);
 	if (!tdata->skb) {
-		pr_warn("alloc skb %u+%u, opcode 0x%x failed.\n",
-			cdev->skb_tx_rsvd, headroom, opcode);
+		struct cxgbi_sock *csk = cconn->cep->csk;
+		struct net_device *ndev = cdev->ports[csk->port_id];
+		ndev->stats.tx_dropped++;
 		return -ENOMEM;
 	}
 
-- 
1.7.4.4

In alloc_pdu, libcxgbi tries to allocate a skb with GFP_ATOMIC, which
may potentially fail. When it happens, the current code prints a warning
message.

When the system is under IO stress, this failure may happen lots of
times and it usually scares users.

Instead of printing the warning message, the code now increases the
tx_dropped statistics for the ethernet interface wich is doing the iscsi
task.

Signed-off-by: Thadeu Lima de Souza Cascardo <redacted>
---
 drivers/scsi/cxgbi/libcxgbi.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c
index c10f74a..3422bc2 100644
--- a/drivers/scsi/cxgbi/libcxgbi.c
+++ b/drivers/scsi/cxgbi/libcxgbi.c

@@ -1862,8 +1862,9 @@ int cxgbi_conn_alloc_pdu(struct iscsi_task *task, u8 opcode)
 
 	tdata->skb = alloc_skb(cdev->skb_tx_rsvd + headroom, GFP_ATOMIC);
 	if (!tdata->skb) {
-		pr_warn("alloc skb %u+%u, opcode 0x%x failed.\n",
-			cdev->skb_tx_rsvd, headroom, opcode);
+		struct cxgbi_sock *csk = cconn->cep->csk;
+		struct net_device *ndev = cdev->ports[csk->port_id];
+		ndev->stats.tx_dropped++;
 		return -ENOMEM;
 	}