Re: [PATCH][V2] scsi: cxgbi: remove redundant __kfree_skb call on skb and free cst->atid

From: Dan Carpenter
Date: Wed Apr 10 2019 - 15:52:41 EST


On Wed, Apr 10, 2019 at 04:54:31PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> The error return path via label rel_resource checks for a non-null
> skb before free'ing it. However, skb is always null at this exit
> path, so the null check and the free are redundant and can be removed.
> Removing this allows the original goto's to rel_resource to be cleaned
> up; the first can be replaced by a return of -EINVAL, the second can
> be replaced by a more appropriate -ENOMEM return and fix a memory
> leak by freeing csk->atid
>
> Addresses-Coverity: ("Logically Dead Code")
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>
> V2: Ensure cst->atid is free'd to fix memory leak, thanks to
> Walter Harms for spotting this mistake in V1.
> ---
> drivers/scsi/cxgbi/cxgb3i/cxgb3i.c | 13 +++++--------
> 1 file changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
> index 75e1273a44b3..15a48c2ac536 100644
> --- a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
> +++ b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c
> @@ -979,14 +979,16 @@ static int init_act_open(struct cxgbi_sock *csk)
> csk->atid = cxgb3_alloc_atid(t3dev, &t3_client, csk);
> if (csk->atid < 0) {
> pr_err("NO atid available.\n");
> - goto rel_resource;
> + return -EINVAL;
> }
> cxgbi_sock_set_flag(csk, CTPF_HAS_ATID);
> cxgbi_sock_get(csk);
^^^^^^^^^^^^^^^^^^^
Don't we need to a put for this as well?

>
> skb = alloc_wr(sizeof(struct cpl_act_open_req), 0, GFP_KERNEL);
> - if (!skb)
> - goto rel_resource;
> + if (!skb) {
> + cxgb3_free_atid(t3dev, csk->atid);
> + return -ENOMEM;
> + }


regards,
dan carpenter