Hello Benjamin Berg,
Commit 7f5e3038f029 ("wifi: iwlwifi: map entire SKB when sending
AMSDUs") from Jul 3, 2024 (linux-next), leads to the following Smatch
static checker warning:
drivers/net/wireless/intel/iwlwifi/pcie/tx.c:1879 iwl_pcie_prep_tso()
warn: error code type promoted to positive: 'sgt->orig_nents'
drivers/net/wireless/intel/iwlwifi/pcie/tx.c
1855 struct sg_table *iwl_pcie_prep_tso(struct iwl_trans *trans, struct sk_buff *skb,
1856 struct iwl_cmd_meta *cmd_meta,
1857 u8 **hdr, unsigned int hdr_room)
1858 {
1859 struct sg_table *sgt;
1860
1861 if (WARN_ON_ONCE(skb_has_frag_list(skb)))
1862 return NULL;
1863
1864 *hdr = iwl_pcie_get_page_hdr(trans,
1865 hdr_room + __alignof__(struct sg_table) +
1866 sizeof(struct sg_table) +
1867 (skb_shinfo(skb)->nr_frags + 1) *
1868 sizeof(struct scatterlist),
1869 skb);
1870 if (!*hdr)
1871 return NULL;
1872
1873 sgt = (void *)PTR_ALIGN(*hdr + hdr_room, __alignof__(struct sg_table));
1874 sgt->sgl = (void *)(sgt + 1);
1875
1876 sg_init_table(sgt->sgl, skb_shinfo(skb)->nr_frags + 1);
1877
1878 sgt->orig_nents = skb_to_sgvec(skb, sgt->sgl, 0, skb->len);
--> 1879 if (WARN_ON_ONCE(sgt->orig_nents <= 0))
skb_to_sgvec() returns negative error codes but sgt->orig_nents is a u32 so
the error handling doesn't work. Need to either change the type or add a cast.
1880 return NULL;
1881
1882 /* And map the entire SKB */
1883 if (dma_map_sgtable(trans->dev, sgt, DMA_TO_DEVICE, 0) < 0)
1884 return NULL;
1885
1886 /* Store non-zero (i.e. valid) offset for unmapping */
1887 cmd_meta->sg_offset = (unsigned long) sgt & ~PAGE_MASK;
1888
1889 return sgt;
1890 }
regards,
dan carpenter
