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* [PATCH] iwlwifi: eeprom-parse: use struct_size() in kzalloc()
@ 2019-01-08 17:17 Gustavo A. R. Silva
  0 siblings, 0 replies; 1+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-08 17:17 UTC (permalink / raw)
  To: Johannes Berg, Emmanuel Grumbach, Luca Coelho,
	Intel Linux Wireless, Kalle Valo, David S. Miller
  Cc: linux-wireless, netdev, linux-kernel, Gustavo A. R. Silva

One of the more common cases of allocation size calculations is finding the
size of a structure that has a zero-sized array at the end, along with memory
for some number of elements for that array. For example:

struct foo {
    int stuff;
    void *entry[];
};

instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can now
use the new struct_size() helper:

instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/net/wireless/intel/iwlwifi/iwl-eeprom-parse.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-eeprom-parse.c b/drivers/net/wireless/intel/iwlwifi/iwl-eeprom-parse.c
index 75940ac406b9..04338c3a6205 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-eeprom-parse.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-eeprom-parse.c
@@ -850,8 +850,7 @@ iwl_parse_eeprom_data(struct device *dev, const struct iwl_cfg *cfg,
 	if (WARN_ON(!cfg || !cfg->eeprom_params))
 		return NULL;
 
-	data = kzalloc(sizeof(*data) +
-		       sizeof(struct ieee80211_channel) * IWL_NUM_CHANNELS,
+	data = kzalloc(struct_size(data, channels, IWL_NUM_CHANNELS),
 		       GFP_KERNEL);
 	if (!data)
 		return NULL;
-- 
2.20.1


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2019-01-08 17:17 [PATCH] iwlwifi: eeprom-parse: use struct_size() in kzalloc() Gustavo A. R. Silva

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