From: Jakub Kicinski <kuba@kernel.org>
To: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Cc: christopher.lee@cspi.com, davem@davemloft.net, pabeni@redhat.com,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RESEND][PATCH v2] myri10ge: remove an unneeded NULL check
Date: Tue, 5 Apr 2022 18:25:14 -0700 [thread overview]
Message-ID: <20220405182514.40fae2d0@kernel.org> (raw)
In-Reply-To: <20220405000553.21856-1-xiam0nd.tong@gmail.com>
On Tue, 5 Apr 2022 08:05:53 +0800 Xiaomeng Tong wrote:
> The define of skb_list_walk_safe(first, skb, next_skb) is:
> for ((skb) = (first), (next_skb) = (skb) ? (skb)->next : NULL; (skb); \
> (skb) = (next_skb), (next_skb) = (skb) ? (skb)->next : NULL)
>
> Thus, if the 'segs' passed as 'first' into the skb_list_walk_safe is NULL,
> the loop will exit immediately. In other words, it can be sure the 'segs'
> is non-NULL when we run inside the loop. So just remove the unnecessary
> NULL check. Also remove the unneeded assignmnets.
>
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
The existing code is pretty clearly buggy. Please fix the bugs or don't
touch it. You're obfuscating what the original intention was.
> diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> index 50ac3ee2577a..071657e3dba8 100644
> --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> @@ -2903,12 +2903,8 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
> status = myri10ge_xmit(curr, dev);
> if (status != 0) {
> dev_kfree_skb_any(curr);
> - if (segs != NULL) {
> - curr = segs;
> - segs = next;
> - curr->next = NULL;
> - dev_kfree_skb_any(segs);
> - }
> + segs->next = NULL;
> + dev_kfree_skb_any(next);
> goto drop;
> }
> }
next prev parent reply other threads:[~2022-04-06 13:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 0:05 [RESEND][PATCH v2] myri10ge: remove an unneeded NULL check Xiaomeng Tong
2022-04-06 1:25 ` Jakub Kicinski [this message]
2022-04-05 0:12 Xiaomeng Tong
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220405182514.40fae2d0@kernel.org \
--to=kuba@kernel.org \
--cc=christopher.lee@cspi.com \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=xiam0nd.tong@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).