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ucounts: Remove unnecessary test for NULL ucount in get_ucounts

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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 <yuzhao@google.com>
Reviewed-by: Alexey Gladkov <legion@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2021-10-16 13:50:48 -05:00
parent 99c31f9fed
commit 5fc9e37cd5
1 changed files with 1 additions and 1 deletions
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2
kernel/ucount.c
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@ -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;
}