[PATCH][next] net: aquantia: fix unsigned numvecs comparison with less than zero

[PATCH][next] net: aquantia: fix unsigned numvecs comparison with less than zero

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

The comparison of numvecs < 0 is always false because numvecs is a u32
and hence the error return from a failed call to pci_alloc_irq_vectores
is never detected.  Fix this by using the signed int ret to handle the
error return and assign numvecs to err.

Detected by CoverityScan, CID#1468650 ("Unsigned compared against 0")

Fixes: a09bd81b5413 ("net: aquantia: Limit number of vectors to actually allocated irqs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c b/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c
index a50e08bb4748..750007513f9d 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c
@@ -267,14 +267,13 @@ static int aq_pci_probe(struct pci_dev *pdev,
 	numvecs = min(numvecs, num_online_cpus());
 	/*enable interrupts */
 #if !AQ_CFG_FORCE_LEGACY_INT
-	numvecs = pci_alloc_irq_vectors(self->pdev, 1, numvecs,
-					PCI_IRQ_MSIX | PCI_IRQ_MSI |
-					PCI_IRQ_LEGACY);
+	err = pci_alloc_irq_vectors(self->pdev, 1, numvecs,
+				    PCI_IRQ_MSIX | PCI_IRQ_MSI |
+				    PCI_IRQ_LEGACY);
 
-	if (numvecs < 0) {
-		err = numvecs;
+	if (err < 0)
 		goto err_hwinit;
-	}
+	numvecs = err;
 #endif
 	self->irqvecs = numvecs;
 
-- 
2.17.0

Re: [PATCH][next] net: aquantia: fix unsigned numvecs comparison with less than zero

[Igor Russkikh]

Thanks, Colin!

> The comparison of numvecs < 0 is always false because numvecs is a u32
> and hence the error return from a failed call to pci_alloc_irq_vectores
> is never detected.  Fix this by using the signed int ret to handle the
> error return and assign numvecs to err.
> 
> Detected by CoverityScan, CID#1468650 ("Unsigned compared against 0")
> 
> Fixes: a09bd81b5413 ("net: aquantia: Limit number of vectors to actually allocated irqs")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---

Acked-by: Igor Russkikh <igor.russkikh@aquantia.com>

Re: [PATCH][next] net: aquantia: fix unsigned numvecs comparison with less than zero

[David Miller]

From: Colin King <colin.king@canonical.com>
Date: Thu, 10 May 2018 13:52:01 +0100

> From: Colin Ian King <colin.king@canonical.com>
> 
> The comparison of numvecs < 0 is always false because numvecs is a u32
> and hence the error return from a failed call to pci_alloc_irq_vectores
> is never detected.  Fix this by using the signed int ret to handle the
> error return and assign numvecs to err.
> 
> Detected by CoverityScan, CID#1468650 ("Unsigned compared against 0")
> 
> Fixes: a09bd81b5413 ("net: aquantia: Limit number of vectors to actually allocated irqs")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

This doesn't apply to net-next.

Re: [PATCH][next] net: aquantia: fix unsigned numvecs comparison with less than zero

[Igor Russkikh]

>> Fixes: a09bd81b5413 ("net: aquantia: Limit number of vectors to actually allocated irqs")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> 
> This doesn't apply to net-next.
> 

Colin, believe thats because you should target to net, not net-next.

BR, Igor