From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Ilya Dryomov <idryomov@gmail.com>, "Yan, Zheng" <zyan@redhat.com>,
Sage Weil <sage@redhat.com>,
"David S. Miller" <davem@davemloft.net>
Cc: ceph-devel@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH net-next] libceph, ceph: use struct_size() in kmalloc()
Date: Tue, 15 Jan 2019 13:41:53 -0600 [thread overview]
Message-ID: <20190115194153.GA9565@embeddedor> (raw)
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>
---
net/ceph/osdmap.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 98c0ff3d6441..48a31dc9161c 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -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);
--
2.20.1
next reply other threads:[~2019-01-15 20:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-15 19:41 Gustavo A. R. Silva [this message]
2019-01-17 14:17 ` [PATCH net-next] libceph, ceph: use struct_size() in kmalloc() Ilya Dryomov
2019-01-25 3:50 ` Gustavo A. R. Silva
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