Returning a difference from a comparison functions is usually wrong (see acbbe6fbb240 "kcmp: fix standard comparison bug" for the long story). Here there is the additional twist that if the void pointers ns and kn->ns happen to differ by a multiple of 2^32, kernfs_name_compare returns 0, falsely reporting a match to the caller.
Technically 'hash - kn->hash' is ok since the hashes are restricted to 31 bits, but it's better to avoid that subtlety. Signed-off-by: Rasmus Villemoes <[email protected]> --- Notes: v2: Also use explicit < > comparisons of the hashes. fs/kernfs/dir.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 1c771931bb60..bf9e2f44c3df 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -201,10 +201,14 @@ static unsigned int kernfs_name_hash(const char *name, const void *ns) static int kernfs_name_compare(unsigned int hash, const char *name, const void *ns, const struct kernfs_node *kn) { - if (hash != kn->hash) - return hash - kn->hash; - if (ns != kn->ns) - return ns - kn->ns; + if (hash < kn->hash) + return -1; + if (hash > kn->hash) + return 1; + if (ns < kn->ns) + return -1; + if (ns > kn->ns) + return 1; return strcmp(name, kn->name); } -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
