Messages in this thread | | | Subject | Re: [PATCH] net: stmmac: ensure jumbo_frm error return is correctly checked for -ve value | From | Colin Ian King <> | Date | Sat, 3 Jun 2017 17:35:22 +0100 |
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On 03/06/17 16:55, Andy Shevchenko wrote: > On Fri, Jun 2, 2017 at 5:58 PM, Colin King <colin.king@canonical.com> wrote: >> The current comparison of entry < 0 will never be true since entry is an >> unsigned integer. Cast entry to an int to ensure -ve error return values >> from the call to jumbo_frm are correctly being caught. > >> if (unlikely(is_jumbo) && likely(priv->synopsys_id < >> DWMAC_CORE_4_00)) { >> entry = priv->hw->mode->jumbo_frm(tx_q, skb, csum_insertion); >> - if (unlikely(entry < 0)) >> + if (unlikely((int)entry < 0)) > > It feels like a hiding some other issue. >
The alternative is:
int rc = priv->hw->mode->jumbo_frm(tx_q, skb, csum_insertion); if (unlikely(rc < 0)) goto dma_map_err;
entry = rc;
however, that is effectively the same. The cast I'm using is a well used idiom in the kernel, it used in almost a hundred similar cases.
git grep "< 0" | grep "(int)" | wc -l 95
Colin
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