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srcu: Fix error handling in init_srcu_struct_fields()

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The current error handling in init_srcu_struct_fields() is a bit
inconsistent.  If init_srcu_struct_nodes() fails, the function either
returns -ENOMEM or 0 depending on whether ssp->sda_is_static is true or
false. This can make init_srcu_struct_fields() return 0 even if memory
allocation failed!

Simplify the error handling by always returning -ENOMEM if either
init_srcu_struct_nodes() or the per-CPU allocation fails. This makes the
control flow easier to follow and avoids the inconsistent return values.

Add goto labels to avoid duplicating the error cleanup code.

Link: https://lore.kernel.org/r/20230404003508.GA254019@google.com
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit is contained in:
Joel Fernandes (Google) 2023-07-29 14:27:32 +00:00 committed by Frederic Weisbecker
parent ff18cb8164
commit f0a31b26be
1 changed files with 17 additions and 15 deletions
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32
kernel/rcu/srcutree.c
View file

@ -255,29 +255,31 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
ssp->srcu_sup->sda_is_static = is_static;
if (!is_static)
ssp->sda = alloc_percpu(struct srcu_data);
if (!ssp->sda) {
if (!is_static)
kfree(ssp->srcu_sup);
return -ENOMEM;
}
if (!ssp->sda)
goto err_free_sup;
init_srcu_struct_data(ssp);
ssp->srcu_sup->srcu_gp_seq_needed_exp = 0;
ssp->srcu_sup->srcu_last_gp_end = ktime_get_mono_fast_ns();
if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && SRCU_SIZING_IS_INIT()) {
if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC)) {
if (!ssp->srcu_sup->sda_is_static) {
free_percpu(ssp->sda);
ssp->sda = NULL;
kfree(ssp->srcu_sup);
return -ENOMEM;
}
} else {
WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG);
}
if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC))
goto err_free_sda;
WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG);
}
ssp->srcu_sup->srcu_ssp = ssp;
smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, 0); /* Init done. */
return 0;
err_free_sda:
if (!is_static) {
free_percpu(ssp->sda);
ssp->sda = NULL;
}
err_free_sup:
if (!is_static) {
kfree(ssp->srcu_sup);
ssp->srcu_sup = NULL;
}
return -ENOMEM;
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC