Commit 2a916f2f authored by David Miller's avatar David Miller Committed by Alexei Starovoitov
Browse files

bpf: Use migrate_disable/enable in array macros and cgroup/lirc code. 



Replace the preemption disable/enable with migrate_disable/enable() to
reflect the actual requirement and to allow PREEMPT_RT to substitute it
with an actual migration disable mechanism which does not disable
preemption.

Including the code paths that go via __bpf_prog_run_save_cb().

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200224145643.998293311@linutronix.de
parent 02ad0596

include/linux/bpf.h

+4 −4
Original line number Diff line number Diff line
@@ -885,7 +885,7 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array, 
		struct bpf_prog *_prog;			\

		struct bpf_prog_array *_array;		\

		u32 _ret = 1;				\

		preempt_disable();			\

		migrate_disable();			\

		rcu_read_lock();			\

		_array = rcu_dereference(array);	\

		if (unlikely(check_non_null && !_array))\
@@ -898,7 +898,7 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array, 
		}					\

_out:							\

		rcu_read_unlock();			\

		preempt_enable();			\

		migrate_enable();			\

		_ret;					\

	 })
@@ -932,7 +932,7 @@ _out: \ 
		u32 ret;				\

		u32 _ret = 1;				\

		u32 _cn = 0;				\

		preempt_disable();			\

		migrate_disable();			\

		rcu_read_lock();			\

		_array = rcu_dereference(array);	\

		_item = &_array->items[0];		\
@@ -944,7 +944,7 @@ _out: \ 
			_item++;			\

		}					\

		rcu_read_unlock();			\

		preempt_enable();			\

		migrate_enable();			\

		if (_ret)				\

			_ret = (_cn ? NET_XMIT_CN : NET_XMIT_SUCCESS);	\

		else					\

include/linux/filter.h

+3 −2
Original line number Diff line number Diff line
@@ -677,6 +677,7 @@ static inline u8 *bpf_skb_cb(struct sk_buff *skb) 
	return qdisc_skb_cb(skb)->data;

}



/* Must be invoked with migration disabled */

static inline u32 __bpf_prog_run_save_cb(const struct bpf_prog *prog,

					 struct sk_buff *skb)

{
@@ -702,9 +703,9 @@ static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog, 
{

	u32 res;



	preempt_disable();

	migrate_disable();

	res = __bpf_prog_run_save_cb(prog, skb);

	preempt_enable();

	migrate_enable();

	return res;

}

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