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libceph: use struct_size() for kmalloc() in crush_decode() 

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;
    struct boo entry[];
};

instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);

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

instance = kmalloc(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>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
hifive-unleashed-5.1
Gustavo A. R. Silva 2019-01-15 13:41:53 -06:00 committed by Ilya Dryomov
parent e3ec8d6898
commit 6b41d4d9cb
1 changed files with 2 additions and 3 deletions
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5
net/ceph/osdmap.c
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@ -495,9 +495,8 @@ static struct crush_map *crush_decode(void *pbyval, void *end)
/ sizeof(struct crush_rule_step))
goto bad;
#endif
r = c->rules[i] = kmalloc(sizeof(*r) +
yes*sizeof(struct crush_rule_step),
GFP_NOFS);
r = kmalloc(struct_size(r, steps, yes), GFP_NOFS);
c->rules[i] = r;
if (r == NULL)
goto badmem;
dout(" rule %d is at %p\n", i, r);