diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-03-12 08:22:50 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-03-18 13:18:36 +0100 |
| commit | ca0359df45a55a9eb4d6dc09a481064abf78320f (patch) | |
| tree | 4a9e6bcd4806324cfaf4b4b67f0fd082d99ae4cb /net/ipv4/inet_fragment.c | |
| parent | eb0dfc0ef195a04e519b15d73cf25d8c25ee8df7 (diff) | |
inet: frags: save a pair of atomic operations in reassembly
As mentioned in commit 648700f76b03 ("inet: frags:
use rhashtables for reassembly units"):
A followup patch will even remove the refcount hold/release
left from prior implementation and save a couple of atomic
operations.
This patch implements this idea, seven years later.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250312082250.1803501-5-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/ipv4/inet_fragment.c')
| -rw-r--r-- | net/ipv4/inet_fragment.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index 5eb186050013..19fae4811ab2 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -327,7 +327,8 @@ static struct inet_frag_queue *inet_frag_alloc(struct fqdir *fqdir, timer_setup(&q->timer, f->frag_expire, 0); spin_lock_init(&q->lock); - refcount_set(&q->refcnt, 3); + /* One reference for the timer, one for the hash table. */ + refcount_set(&q->refcnt, 2); return q; } @@ -349,7 +350,11 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, *prev = rhashtable_lookup_get_insert_key(&fqdir->rhashtable, &q->key, &q->node, f->rhash_params); if (*prev) { - int refs = 2; + /* We could not insert in the hash table, + * we need to cancel what inet_frag_alloc() + * anticipated. + */ + int refs = 1; q->flags |= INET_FRAG_COMPLETE; inet_frag_kill(q, &refs); @@ -359,7 +364,6 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, return q; } -/* TODO : call from rcu_read_lock() and no longer use refcount_inc_not_zero() */ struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) { /* This pairs with WRITE_ONCE() in fqdir_pre_exit(). */ @@ -369,17 +373,11 @@ struct inet_frag_queue *inet_frag_find(struct fqdir *fqdir, void *key) if (!high_thresh || frag_mem_limit(fqdir) > high_thresh) return NULL; - rcu_read_lock(); - prev = rhashtable_lookup(&fqdir->rhashtable, key, fqdir->f->rhash_params); if (!prev) fq = inet_frag_create(fqdir, key, &prev); - if (!IS_ERR_OR_NULL(prev)) { + if (!IS_ERR_OR_NULL(prev)) fq = prev; - if (!refcount_inc_not_zero(&fq->refcnt)) - fq = NULL; - } - rcu_read_unlock(); return fq; } EXPORT_SYMBOL(inet_frag_find); |