[PATCH 1/1] net: ethernet: qlogic: set error code on failure

[PATCH 1/1] net: ethernet: qlogic: set error code on failure

[Pan Bian]

From: Pan Bian <bianpan2016@163.com>

When calling dma_mapping_error(), the value of return variable rc is 0.
And when the call returns an unexpected value, rc is not set to a
negative errno. Thus, it will return 0 on the error path, and its
callers cannot detect the bug. This patch fixes the bug, assigning
"-ENOMEM" to err.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=189041

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/net/ethernet/qlogic/qed/qed_ll2.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_ll2.c b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
index f95385c..62ae55b 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_ll2.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_ll2.c
@@ -1730,6 +1730,7 @@ static int qed_ll2_start_xmit(struct qed_dev *cdev, struct sk_buff *skb)
 						       mapping))) {
 				DP_NOTICE(cdev,
 					  "Unable to map frag - dropping packet\n");
+				rc = -ENOMEM;
 				goto err;
 			}
 		} else {
-- 
1.9.1

RE: [PATCH 1/1] net: ethernet: qlogic: set error code on failure

[Mintz, Yuval]

> From: Pan Bian <bianpan2016@163.com>
> 
> When calling dma_mapping_error(), the value of return variable rc is 0.
> And when the call returns an unexpected value, rc is not set to a negative
> errno. Thus, it will return 0 on the error path, and its callers cannot detect
> the bug. This patch fixes the bug, assigning "-ENOMEM" to err.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=189041
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>

The title should have been "[PATCH net 1/1] qed: Set error code on failure".

But the fix itself is sound. Thanks.
BTW, is -ENOMEM the right return code in case of DMA mapping errors?

Acked-by: Yuval Mintz <Yuval.Mintz@cavium.com>

Re: [PATCH 1/1] net: ethernet: qlogic: set error code on failure

[David Miller]

From: "Mintz, Yuval" <Yuval.Mintz@cavium.com>
Date: Sun, 4 Dec 2016 07:29:58 +0000

>> From: Pan Bian <bianpan2016@163.com>
>> 
>> When calling dma_mapping_error(), the value of return variable rc is 0.
>> And when the call returns an unexpected value, rc is not set to a negative
>> errno. Thus, it will return 0 on the error path, and its callers cannot detect
>> the bug. This patch fixes the bug, assigning "-ENOMEM" to err.
>> 
>> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=189041
>> 
>> Signed-off-by: Pan Bian <bianpan2016@163.com>
> 
> The title should have been "[PATCH net 1/1] qed: Set error code on failure".
> 
> But the fix itself is sound. Thanks.
> BTW, is -ENOMEM the right return code in case of DMA mapping errors?
> 
> Acked-by: Yuval Mintz <Yuval.Mintz@cavium.com>

Applied.

Indeed, -ENOMEM is usually the right thing to use for DMA mapping errors.
Because usually the error is because we're run out of IOMMU resources
or similar.  And -ENOMEM is pretty much the error code which maps most
closely to that situation.