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pf: atomically increment state ids

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Rather than using a per-cpu state counter, and adding in the CPU id we
can atomically increment the number.
This has the advantage of removing the assumption that the CPU ID fits
in 8 bits.

Event:		Aberdeen Hackathon 2022
Reviewed by:	mjg
Differential Revision:	https://reviews.freebsd.org/D36915
This commit is contained in:
Kristof Provost 2022-10-07 19:17:06 +02:00
parent 5b966d7871
commit 133935d26f
3 changed files with 4 additions and 16 deletions
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2
sys/net/pfvar.h
View File

@ -1987,7 +1987,7 @@ VNET_DECLARE(void *, pf_swi_cookie);
VNET_DECLARE(struct intr_event *, pf_swi_ie);
#define V_pf_swi_ie VNET(pf_swi_ie)
VNET_DECLARE(uint64_t, pf_stateid[MAXCPU]);
VNET_DECLARE(struct unrhdr64, pf_stateid);
#define V_pf_stateid VNET(pf_stateid)
TAILQ_HEAD(pf_altqqueue, pf_altq);

12
sys/netpfil/pf/pf.c
View File

@ -249,12 +249,7 @@ uma_zone_t pf_mtag_z;
VNET_DEFINE(uma_zone_t, pf_state_z);
VNET_DEFINE(uma_zone_t, pf_state_key_z);
VNET_DEFINE(uint64_t, pf_stateid[MAXCPU]);
#define PFID_CPUBITS 8
#define PFID_CPUSHIFT (sizeof(uint64_t) * NBBY - PFID_CPUBITS)
#define PFID_CPUMASK ((uint64_t)((1 << PFID_CPUBITS) - 1) << PFID_CPUSHIFT)
#define PFID_MAXID (~PFID_CPUMASK)
CTASSERT((1 << PFID_CPUBITS) >= MAXCPU);
VNET_DEFINE(struct unrhdr64, pf_stateid);
static void pf_src_tree_remove_state(struct pf_kstate *);
static void pf_init_threshold(struct pf_threshold *, u_int32_t,
@ -1416,10 +1411,7 @@ pf_state_insert(struct pfi_kkif *kif, struct pfi_kkif *orig_kif,
s->orig_kif = orig_kif;
if (s->id == 0 && s->creatorid == 0) {
/* XXX: should be atomic, but probability of collision low */
if ((s->id = V_pf_stateid[curcpu]++) == PFID_MAXID)
V_pf_stateid[curcpu] = 1;
s->id |= (uint64_t )curcpu << PFID_CPUSHIFT;
s->id = alloc_unr64(&V_pf_stateid);
s->id = htobe64(s->id);
s->creatorid = V_pf_status.hostid;
}

6
sys/netpfil/pf/pf_ioctl.c
View File

@ -2595,16 +2595,12 @@ pfioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, struct thread *td
if (V_pf_status.running)
error = EEXIST;
else {
int cpu;
hook_pf();
if (! TAILQ_EMPTY(V_pf_keth->active.rules))
hook_pf_eth();
V_pf_status.running = 1;
V_pf_status.since = time_second;
CPU_FOREACH(cpu)
V_pf_stateid[cpu] = time_second;
new_unrhdr64(&V_pf_stateid, time_second);
DPFPRINTF(PF_DEBUG_MISC, ("pf: started\n"));
}