Patchwork [06/10] drivers:ethernet: return -ENOMEM on allocation failure.

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Submitter Allen
Date Sept. 13, 2017, 7:32 a.m.
Message ID <1505287939-14106-6-git-send-email-allen.lkml@gmail.com>
Download mbox | patch
Permalink /patch/9950495/
State Not Applicable
Delegated to: Herbert Xu
Headers show

Comments

Allen - Sept. 13, 2017, 7:32 a.m.
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
---
 drivers/net/ethernet/sun/cassini.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Andrew Lunn - Sept. 13, 2017, 12:16 p.m.
On Wed, Sep 13, 2017 at 01:02:15PM +0530, Allen Pais wrote:
> Signed-off-by: Allen Pais <allen.lkml@gmail.com>
> ---
>  drivers/net/ethernet/sun/cassini.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
> index 382993c..fc0ea3a 100644
> --- a/drivers/net/ethernet/sun/cassini.c
> +++ b/drivers/net/ethernet/sun/cassini.c
> @@ -3984,7 +3984,7 @@ static inline int cas_alloc_rx_desc(struct cas *cp, int ring)
>  	size = RX_DESC_RINGN_SIZE(ring);
>  	for (i = 0; i < size; i++) {
>  		if ((page[i] = cas_page_alloc(cp, GFP_KERNEL)) == NULL)
> -			return -1;
> +			return -ENOMEM;
>  	}
>  	return 0;
>  }

static int cas_alloc_rxds(struct cas *cp)
{
	int i;

	for (i = 0; i < N_RX_DESC_RINGS; i++) {
		if (cas_alloc_rx_desc(cp, i) < 0) {
	       		cas_free_rxds(cp);
			return -1;
		}
	}
	return 0;
}

Again, your change is correct, but in the end the value is not used.
And if you fix it at the cas_alloc_rxds level, you also need a fix at
the next level up:

	err = -ENOMEM;
	if (cas_tx_tiny_alloc(cp) < 0)
		goto err_unlock;

	/* alloc rx descriptors */
	if (cas_alloc_rxds(cp) < 0)
		goto err_tx_tiny;

again, the return value is discarded.

       Andrew
Allen - Sept. 13, 2017, 1:04 p.m.
>
> static int cas_alloc_rxds(struct cas *cp)
> {
>         int i;
>
>         for (i = 0; i < N_RX_DESC_RINGS; i++) {
>                 if (cas_alloc_rx_desc(cp, i) < 0) {
>                         cas_free_rxds(cp);
>                         return -1;
>                 }
>         }
>         return 0;
> }
>
> Again, your change is correct, but in the end the value is not used.
> And if you fix it at the cas_alloc_rxds level, you also need a fix at
> the next level up:
>
>         err = -ENOMEM;
>         if (cas_tx_tiny_alloc(cp) < 0)
>                 goto err_unlock;
>
>         /* alloc rx descriptors */
>         if (cas_alloc_rxds(cp) < 0)
>                 goto err_tx_tiny;
>
> again, the return value is discarded.

 I agree. I could send out v2 with fixes at both level.

- Allen
David Miller - Sept. 13, 2017, 4:20 p.m.
From: Allen Pais <allen.lkml@gmail.com>
Date: Wed, 13 Sep 2017 13:02:15 +0530

> Signed-off-by: Allen Pais <allen.lkml@gmail.com>

This is quite pointless as the caller doesn't do anything with
the value, it just tests whether a negative value is returned
or not.

Patch

diff --git a/drivers/net/ethernet/sun/cassini.c b/drivers/net/ethernet/sun/cassini.c
index 382993c..fc0ea3a 100644
--- a/drivers/net/ethernet/sun/cassini.c
+++ b/drivers/net/ethernet/sun/cassini.c
@@ -3984,7 +3984,7 @@  static inline int cas_alloc_rx_desc(struct cas *cp, int ring)
 	size = RX_DESC_RINGN_SIZE(ring);
 	for (i = 0; i < size; i++) {
 		if ((page[i] = cas_page_alloc(cp, GFP_KERNEL)) == NULL)
-			return -1;
+			return -ENOMEM;
 	}
 	return 0;
 }