[src/trunk]: src/sys/net/npf Avoid LOCKDEBUG pserialize panic by implementing...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7227d050b8bd
branches:  trunk
changeset: 457129:7227d050b8bd
user:      christos <christos%NetBSD.org@localhost>
date:      Wed Jun 12 14:36:32 2019 +0000

description:
Avoid LOCKDEBUG pserialize panic by implementing suggestion #1 from

    http://mail-index.netbsd.org/current-users/2019/02/24/msg035220.html:

Convert the mutex to spin-lock at IPL_NET (but it is excessive) and
convert the memory allocations in that code path to KM_NOSLEEP.

diffstat:

 sys/net/npf/lpm.c          |  23 ++++++++++++++---------
 sys/net/npf/lpm.h          |   2 +-
 sys/net/npf/npf_tableset.c |   6 +++---
 3 files changed, 18 insertions(+), 13 deletions(-)

diffs (131 lines):

diff -r e71852cbc40f -r 7227d050b8bd sys/net/npf/lpm.c
--- a/sys/net/npf/lpm.c Wed Jun 12 14:28:38 2019 +0000
+++ b/sys/net/npf/lpm.c Wed Jun 12 14:36:32 2019 +0000
@@ -38,7 +38,7 @@
 
 #if defined(_KERNEL)
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lpm.c,v 1.5 2018/09/29 14:41:36 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lpm.c,v 1.6 2019/06/12 14:36:32 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -90,6 +90,7 @@
 
 struct lpm {
        uint32_t        bitmask[LPM_MAX_WORDS];
+       int             flags;
        void *          defvals[2];
        lpm_hmap_t      prefix[LPM_MAX_PREFIX + 1];
 };
@@ -97,9 +98,11 @@
 static const uint32_t zero_address[LPM_MAX_WORDS];
 
 lpm_t *
-lpm_create(void)
+lpm_create(int flags)
 {
-       return kmem_zalloc(sizeof(lpm_t), KM_SLEEP);
+       lpm_t *lpm = kmem_zalloc(sizeof(*lpm), KM_SLEEP);
+       lpm->flags = flags;
+       return lpm;
 }
 
 void
@@ -164,7 +167,7 @@
 }
 
 static bool
-hashmap_rehash(lpm_hmap_t *hmap, unsigned size)
+hashmap_rehash(lpm_hmap_t *hmap, unsigned size, int flags)
 {
        lpm_ent_t **bucket;
        unsigned hashsize;
@@ -172,7 +175,9 @@
        for (hashsize = 1; hashsize < size; hashsize <<= 1) {
                continue;
        }
-       bucket = kmem_zalloc(hashsize * sizeof(lpm_ent_t *), KM_SLEEP);
+       bucket = kmem_zalloc(hashsize * sizeof(lpm_ent_t *), flags);
+       if (bucket == NULL)
+               return false;
        for (unsigned n = 0; n < hmap->hashsize; n++) {
                lpm_ent_t *list = hmap->bucket[n];
 
@@ -194,14 +199,14 @@
 }
 
 static lpm_ent_t *
-hashmap_insert(lpm_hmap_t *hmap, const void *key, size_t len)
+hashmap_insert(lpm_hmap_t *hmap, const void *key, size_t len, int flags)
 {
        const unsigned target = hmap->nitems + LPM_HASH_STEP;
        const size_t entlen = offsetof(lpm_ent_t, key[len]);
        uint32_t hash, i;
        lpm_ent_t *entry;
 
-       if (hmap->hashsize < target && !hashmap_rehash(hmap, target)) {
+       if (hmap->hashsize < target && !hashmap_rehash(hmap, target, flags)) {
                return NULL;
        }
 
@@ -215,7 +220,7 @@
                entry = entry->next;
        }
 
-       if ((entry = kmem_alloc(entlen, KM_SLEEP)) != NULL) {
+       if ((entry = kmem_alloc(entlen, flags)) != NULL) {
                memcpy(entry->key, key, len);
                entry->next = hmap->bucket[i];
                entry->len = len;
@@ -326,7 +331,7 @@
                return 0;
        }
        compute_prefix(nwords, addr, preflen, prefix);
-       entry = hashmap_insert(&lpm->prefix[preflen], prefix, len);
+       entry = hashmap_insert(&lpm->prefix[preflen], prefix, len, lpm->flags);
        if (entry) {
                const unsigned n = --preflen >> 5;
                lpm->bitmask[n] |= 0x80000000U >> (preflen & 31);
diff -r e71852cbc40f -r 7227d050b8bd sys/net/npf/lpm.h
--- a/sys/net/npf/lpm.h Wed Jun 12 14:28:38 2019 +0000
+++ b/sys/net/npf/lpm.h Wed Jun 12 14:36:32 2019 +0000
@@ -32,7 +32,7 @@
 typedef struct lpm lpm_t;
 typedef void (*lpm_dtor_t)(void *, const void *, size_t, void *);
 
-lpm_t *                lpm_create(void);
+lpm_t *                lpm_create(int);
 void           lpm_destroy(lpm_t *);
 void           lpm_clear(lpm_t *, lpm_dtor_t, void *);
 
diff -r e71852cbc40f -r 7227d050b8bd sys/net/npf/npf_tableset.c
--- a/sys/net/npf/npf_tableset.c        Wed Jun 12 14:28:38 2019 +0000
+++ b/sys/net/npf/npf_tableset.c        Wed Jun 12 14:36:32 2019 +0000
@@ -39,7 +39,7 @@
 
 #ifdef _KERNEL
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: npf_tableset.c,v 1.29 2019/01/19 21:19:32 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: npf_tableset.c,v 1.30 2019/06/12 14:36:32 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -365,7 +365,7 @@
 
        switch (type) {
        case NPF_TABLE_LPM:
-               t->t_lpm = lpm_create();
+               t->t_lpm = lpm_create(KM_NOSLEEP);
                if (t->t_lpm == NULL) {
                        goto out;
                }
@@ -398,7 +398,7 @@
        default:
                KASSERT(false);
        }
-       mutex_init(&t->t_lock, MUTEX_DEFAULT, IPL_NONE);
+       mutex_init(&t->t_lock, MUTEX_DEFAULT, IPL_NET);
        t->t_type = type;
        t->t_id = tid;
        return t;