[PATCH v2] err.h: allow IS_ERR_VALUE to handle properly more types

[Andrzej Hajda]

Current implementation of IS_ERR_VALUE works correctly only with
following types:
- unsigned long,
- short, int, long.
Other types are handled incorrectly either on 32-bit either on 64-bit
either on both architectures.
The patch fixes it by comparing argument with MAX_ERRNO casted
to argument's type for unsigned types and comparing with zero for signed
types. As a result all integer types bigger than char are handled properly.

I have analyzed usage of IS_ERR_VALUE using coccinelle and in about 35
cases it is used incorrectly, ie it can hide errors depending of 32/64 bit
architecture. Instead of fixing usage I propose to enhance the macro
to cover more types.
And just for the record: the macro is used 101 times with signed variables,
I am not sure if it should be preferred over simple comparison "ret < 0",
but the new version can do it as well.

And below list of detected potential errors:
drivers/char/mem.c:698:45-46: WARNING: incorrect argument type in IS_ERR_VALUE(( unsigned long long ) offset)
drivers/media/platform/soc_camera/atmel-isi.c:1089:21-22: WARNING: incorrect argument type in IS_ERR_VALUE(irq)
drivers/net/ethernet/freescale/fs_enet/mac-scc.c:149:36-37: WARNING: incorrect argument type in IS_ERR_VALUE(fep -> ring_mem_addr)
drivers/net/ethernet/freescale/ucc_geth.c:2237:48-49: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> tx_bd_ring_offset [ j ])
drivers/net/ethernet/freescale/ucc_geth.c:2314:48-49: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> rx_bd_ring_offset [ j ])
drivers/net/ethernet/freescale/ucc_geth.c:2524:44-45: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> tx_glbl_pram_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2544:45-46: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> thread_dat_tx_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2571:46-47: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> send_q_mem_reg_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2612:42-43: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> scheduler_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2659:54-55: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> tx_fw_statistics_pram_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2696:44-45: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> rx_glbl_pram_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2715:45-46: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> thread_dat_rx_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2736:54-55: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> rx_fw_statistics_pram_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2756:53-54: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> rx_irq_coalescing_tbl_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2822:44-45: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> rx_bd_qs_tbl_offset)
drivers/net/ethernet/freescale/ucc_geth.c:2908:47-48: WARNING: incorrect argument type in IS_ERR_VALUE(ugeth -> exf_glbl_param_offset)
drivers/net/ethernet/freescale/ucc_geth.c:292:36-37: WARNING: incorrect argument type in IS_ERR_VALUE(init_enet_offset)
drivers/net/ethernet/freescale/ucc_geth.c:3042:39-40: WARNING: incorrect argument type in IS_ERR_VALUE(init_enet_pram_offset)
drivers/soc/fsl/qe/ucc_fast.c:271:60-61: WARNING: incorrect argument type in IS_ERR_VALUE(uccf -> ucc_fast_tx_virtual_fifo_base_offset)
drivers/soc/fsl/qe/ucc_fast.c:284:60-61: WARNING: incorrect argument type in IS_ERR_VALUE(uccf -> ucc_fast_rx_virtual_fifo_base_offset)
drivers/soc/fsl/qe/ucc_slow.c:186:38-39: WARNING: incorrect argument type in IS_ERR_VALUE(uccs -> us_pram_offset)
drivers/soc/fsl/qe/ucc_slow.c:213:38-39: WARNING: incorrect argument type in IS_ERR_VALUE(uccs -> rx_base_offset)
drivers/soc/fsl/qe/ucc_slow.c:224:38-39: WARNING: incorrect argument type in IS_ERR_VALUE(uccs -> tx_base_offset)
drivers/tty/serial/clps711x.c:471:29-30: WARNING: incorrect argument type in IS_ERR_VALUE(s -> port . irq)
drivers/tty/serial/digicolor-usart.c:485:30-31: WARNING: incorrect argument type in IS_ERR_VALUE(dp -> port . irq)
drivers/usb/gadget/udc/fsl_qe_udc.c:2369:26-27: WARNING: incorrect argument type in IS_ERR_VALUE(tmp_addr)
drivers/video/fbdev/exynos/exynos_mipi_dsi.c:406:27-28: WARNING: incorrect argument type in IS_ERR_VALUE(dsim -> irq)
net/ipv4/netfilter/arp_tables.c:1427:39-40: WARNING: incorrect argument type in IS_ERR_VALUE(iter1 -> counters . pcnt)
net/ipv4/netfilter/arp_tables.c:530:34-35: WARNING: incorrect argument type in IS_ERR_VALUE(e -> counters . pcnt)
net/ipv4/netfilter/ip_tables.c:1614:34-35: WARNING: incorrect argument type in IS_ERR_VALUE(e -> counters . pcnt)
net/ipv4/netfilter/ip_tables.c:674:34-35: WARNING: incorrect argument type in IS_ERR_VALUE(e -> counters . pcnt)
net/ipv6/netfilter/ip6_tables.c:1624:34-35: WARNING: incorrect argument type in IS_ERR_VALUE(e -> counters . pcnt)
net/ipv6/netfilter/ip6_tables.c:687:34-35: WARNING: incorrect argument type in IS_ERR_VALUE(e -> counters . pcnt)
drivers/net/ethernet/freescale/fs_enet/mac-fcc.c:110:35-36: WARNING: unknown argument type in IS_ERR_VALUE(fpi -> dpram_offset)

Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
---
v2:
 - use '<= 0' instead of '< 0' to silence gcc verbose warnings,
 - expand commit message.
---
 include/linux/err.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/err.h b/include/linux/err.h
index 56762ab..43a6adb 100644
--- a/include/linux/err.h
+++ b/include/linux/err.h
@@ -18,7 +18,9 @@
 
 #ifndef __ASSEMBLY__
 
-#define IS_ERR_VALUE(x) unlikely((x) >= (unsigned long)-MAX_ERRNO)
+#define IS_ERR_VALUE(x) ((typeof(x))(-1) <= 0 \
+				? unlikely((x) < 0) \
+				: unlikely((x) >= (typeof(x))-MAX_ERRNO))
 
 static inline void * __must_check ERR_PTR(long error)
 {
-- 
1.9.1