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Commit cae1927c authored by Jakub Kicinski's avatar Jakub Kicinski Committed by Daniel Borkmann
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bpf: offload: allow netdev to disappear while verifier is running 



To allow verifier instruction callbacks without any extra locking
NETDEV_UNREGISTER notification would wait on a waitqueue for verifier
to finish.  This design decision was made when rtnl lock was providing
all the locking.  Use the read/write lock instead and remove the
workqueue.

Verifier will now call into the offload code, so dev_ops are moved
to offload structure.  Since verifier calls are all under
bpf_prog_is_dev_bound() we no longer need static inline implementations
to please builds with CONFIG_NET=n.

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 9a18eedb

drivers/net/ethernet/netronome/nfp/bpf/main.h

+1 −1
Original line number Diff line number Diff line
@@ -238,7 +238,7 @@ struct nfp_bpf_vnic { 


int nfp_bpf_jit(struct nfp_prog *prog);



extern const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops;

extern const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops;



struct netdev_bpf;

struct nfp_app;

drivers/net/ethernet/netronome/nfp/bpf/verifier.c

+1 −1
Original line number Diff line number Diff line
@@ -260,6 +260,6 @@ nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx) 
	return 0;

}



const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops = {

const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops = {

	.insn_hook = nfp_verify_insn,

};

drivers/net/netdevsim/bpf.c

+1 −1
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ nsim_bpf_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn) 
	return 0;

}



static const struct bpf_ext_analyzer_ops nsim_bpf_analyzer_ops = {

static const struct bpf_prog_offload_ops nsim_bpf_analyzer_ops = {

	.insn_hook = nsim_bpf_verify_insn,

};

include/linux/bpf.h

+7 −2
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/numa.h>

#include <linux/wait.h>



struct bpf_verifier_env;

struct perf_event;

struct bpf_prog;

struct bpf_map;
@@ -184,14 +185,18 @@ struct bpf_verifier_ops { 
				  struct bpf_prog *prog, u32 *target_size);

};



struct bpf_prog_offload_ops {

	int (*insn_hook)(struct bpf_verifier_env *env,

			 int insn_idx, int prev_insn_idx);

};



struct bpf_dev_offload {

	struct bpf_prog		*prog;

	struct net_device	*netdev;

	void			*dev_priv;

	struct list_head	offloads;

	bool			dev_state;

	bool			verifier_running;

	wait_queue_head_t	verifier_done;

	const struct bpf_prog_offload_ops *dev_ops;

};



struct bpf_prog_aux {

include/linux/bpf_verifier.h

+2 −14
Original line number Diff line number Diff line
@@ -166,12 +166,6 @@ static inline bool bpf_verifier_log_full(const struct bpf_verifer_log *log) 
	return log->len_used >= log->len_total - 1;

}



struct bpf_verifier_env;

struct bpf_ext_analyzer_ops {

	int (*insn_hook)(struct bpf_verifier_env *env,

			 int insn_idx, int prev_insn_idx);

};



#define BPF_MAX_SUBPROGS 256



/* single container for all structs
@@ -185,7 +179,6 @@ struct bpf_verifier_env { 
	bool strict_alignment;		/* perform strict pointer alignment checks */

	struct bpf_verifier_state *cur_state; /* current verifier state */

	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */

	const struct bpf_ext_analyzer_ops *dev_ops; /* device analyzer ops */

	struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */

	u32 used_map_cnt;		/* number of used maps */

	u32 id_gen;			/* used to generate unique reg IDs */
@@ -206,13 +199,8 @@ static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env) 
	return cur->frame[cur->curframe]->regs;

}



#if defined(CONFIG_NET) && defined(CONFIG_BPF_SYSCALL)

int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env);

#else

static inline int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env)

{

	return -EOPNOTSUPP;

}

#endif

int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,

				 int insn_idx, int prev_insn_idx);



#endif /* _LINUX_BPF_VERIFIER_H */