From: Jani Nikula <jani.nikula@xxxxxxxxx> Subject: relay: require non-NULL callbacks in relay_open() There are no clients passing NULL callbacks, which makes sense as it wouldn't even create a file. Require non-NULL callbacks, and throw away the handling for NULL callbacks. Link: https://lkml.kernel.org/r/e40642f3b027d2bb6bc851ddb60e0a61ea51f5f8.1606153547.git.jani.nikula@xxxxxxxxx Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/relay.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) --- a/kernel/relay.c~relay-require-non-null-callbacks-in-relay_open +++ a/kernel/relay.c @@ -291,13 +291,6 @@ static int remove_buf_file_default_callb return -EINVAL; } -/* relay channel default callbacks */ -static struct rchan_callbacks default_channel_callbacks = { - .subbuf_start = subbuf_start_default_callback, - .create_buf_file = create_buf_file_default_callback, - .remove_buf_file = remove_buf_file_default_callback, -}; - /** * wakeup_readers - wake up readers waiting on a channel * @work: contains the channel buffer @@ -472,11 +465,6 @@ static void relay_close_buf(struct rchan static void setup_callbacks(struct rchan *chan, struct rchan_callbacks *cb) { - if (!cb) { - chan->cb = &default_channel_callbacks; - return; - } - if (!cb->subbuf_start) cb->subbuf_start = subbuf_start_default_callback; if (!cb->create_buf_file) @@ -542,6 +530,8 @@ struct rchan *relay_open(const char *bas return NULL; if (subbuf_size > UINT_MAX / n_subbufs) return NULL; + if (!cb) + return NULL; chan = kzalloc(sizeof(struct rchan), GFP_KERNEL); if (!chan) _
