From fe785f56ad5886c08d1cadd9e8b4e1ff6a1866f6 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Thu, 18 Nov 2021 15:21:02 +0100
Subject: [PATCH] iwlwifi: pcie: fix constant-conversion warning
Git-commit: fe785f56ad5886c08d1cadd9e8b4e1ff6a1866f6
Patch-mainline: v5.16-rc4
References: bsc#1202131
Both gcc-11 and clang point out a potential issue with integer overflow when
the iwl_dev_info_table[] array is empty. This is what clang warns:
drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1344:42: error: implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1 [-Werror,-Wconstant-conversion]
for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
This is still harmless, as the loop correctly terminates, but adding
an extra range check makes that obvious to both readers and to the
compiler.
Fixes: 3f7320428fa4 ("iwlwifi: pcie: simplify iwl_pci_find_dev_info()")
Reported-by: kernel test robot <lkp@intel.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211118142124.526901-1-arnd@kernel.org
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/wireless/intel/iwlwifi/pcie/drv.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
index c574f041f096..395e328c6a07 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
@@ -1339,9 +1339,13 @@ iwl_pci_find_dev_info(u16 device, u16 subsystem_device,
u16 mac_type, u8 mac_step,
u16 rf_type, u8 cdb, u8 rf_id, u8 no_160, u8 cores)
{
+ int num_devices = ARRAY_SIZE(iwl_dev_info_table);
int i;
- for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
+ if (!num_devices)
+ return NULL;
+
+ for (i = num_devices - 1; i >= 0; i--) {
const struct iwl_dev_info *dev_info = &iwl_dev_info_table[i];
if (dev_info->device != (u16)IWL_CFG_ANY &&
--
2.35.3