From: Eric W. Biederman Date: Sat, 16 Oct 2021 18:50:48 +0000 (-0500) Subject: ucounts: Remove unnecessary test for NULL ucount in get_ucounts X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5fc9e37cd5ae762b856912cdedb226a884b3c3e0;p=linux.git ucounts: Remove unnecessary test for NULL ucount in get_ucounts All of the callers of get_ucounts are passeds a non-NULL value so stop handling a NULL ucounts pointer in get_ucounts. It is guaranteed that ever valid fully formed cred that is passed to commit_cred contains a non-NULL ucounts pointer. This in turn gurantees that current_ucounts() never returns NULL. The call of get_ucounts in user_shm_lock is always passed current_ucounts(). The call of get_ucounts in mqueue_get_inode is always passed current_ucounts(). The call of get_ucounts in inc_rlmit_get_ucounts is always passed iter, after iter has been verified to be non-NULL. The call of get_ucounts in key_change_session_keyring is always passed current_ucounts(). The call of get_ucounts in prepare_cred is always passed current_ucounts(). The call of get_ucounts in prepare_kernel_cred is always passed task->cred->ucounts or init_cred->ucounts which being on tasks are guaranteed to have a non-NULL ucounts field. Link: https://lkml.kernel.org/r/87v91uqksg.fsf_-_@disp2133 Tested-by: Yu Zhao Reviewed-by: Alexey Gladkov Signed-off-by: "Eric W. Biederman" --- diff --git a/kernel/ucount.c b/kernel/ucount.c index eb03f3c68375d..708d05164a7dd 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -152,7 +152,7 @@ static void hlist_add_ucounts(struct ucounts *ucounts) struct ucounts *get_ucounts(struct ucounts *ucounts) { - if (ucounts && atomic_add_negative(1, &ucounts->count)) { + if (atomic_add_negative(1, &ucounts->count)) { put_ucounts(ucounts); ucounts = NULL; }