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| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2020-02-13 10:00:04 -0600 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2020-03-30 12:42:40 +0200 |
| commit | f682dc713c0af79effde49209f3895072579791b (patch) | |
| tree | 4e3bce7dba6d3ce7513eb154baae49221f53921e /fs/ceph | |
| parent | f9b6b98d24f7cec5b8269217f9d4fdec1ca43218 (diff) | |
| download | linux-f682dc713c0af79effde49209f3895072579791b.tar.bz2 | |
ceph: replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'fs/ceph')
| -rw-r--r-- | fs/ceph/cache.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c index 270b769607a2..2f5cb6bc78e1 100644 --- a/fs/ceph/cache.c +++ b/fs/ceph/cache.c @@ -32,7 +32,7 @@ struct ceph_fscache_entry { size_t uniq_len; /* The following members must be last */ struct ceph_fsid fsid; - char uniquifier[0]; + char uniquifier[]; }; static const struct fscache_cookie_def ceph_fscache_fsid_object_def = { |