Refactor the nsm_get_handle() function so it uses the same lookup
helpers as the newly added nsm_reboot_lookup() function, and use
do {} while() instead of a goto; for the retry loop.
This makes it easier if some day we want to use a more sophisticated
lookup algorithm than a linked list search for finding nsm_handles
in both nsm_get_handle() and nsm_reboot_lookup().
There is an additional micro-optimization here. This change moves the
"hostname & nsm_use_hostnames" test out of the list_for_each_entry()
clause in nsm_get_handle(), since it is loop-invariant.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
fs/lockd/mon.c | 70 +++++++++++++++++++++++++++++++-------------------------
1 files changed, 39 insertions(+), 31 deletions(-)
diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 427d915..8538180 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -196,6 +196,16 @@ static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
return NULL;
}
+static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
+{
+ struct nsm_handle *nsm;
+
+ list_for_each_entry(nsm, &nsm_handles, sm_link)
+ if (nlm_cmp_addr(nsm_addr(nsm), sap))
+ return nsm;
+ return NULL;
+}
+
/*
* Construct a unique cookie to identify this nsm_handle. It is
* passed to our statd via NSMPROC_MON, and returned via
@@ -279,8 +289,7 @@ struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
const size_t salen, const char *hostname,
const size_t hostname_len)
{
- struct nsm_handle *nsm = NULL;
- struct nsm_handle *pos;
+ struct nsm_handle *new, *cached;
if (!sap)
return NULL;
@@ -294,39 +303,38 @@ struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
return NULL;
}
-retry:
- spin_lock(&nsm_lock);
- list_for_each_entry(pos, &nsm_handles, sm_link) {
- if (hostname && nsm_use_hostnames) {
- if (strlen(pos->sm_name) != hostname_len
- || memcmp(pos->sm_name, hostname, hostname_len))
- continue;
- } else if (!nlm_cmp_addr(nsm_addr(pos), sap))
- continue;
-
- atomic_inc(&pos->sm_count);
- spin_unlock(&nsm_lock);
- kfree(nsm);
- dprintk("lockd: found nsm_handle for %s (%s), cnt %d\n",
- pos->sm_name, pos->sm_addrbuf,
- atomic_read(&pos->sm_count));
- return pos;
- }
+ new = NULL;
+ do {
+ spin_lock(&nsm_lock);
+
+ if (nsm_use_hostnames && hostname)
+ cached = nsm_lookup_hostname(hostname, hostname_len);
+ else
+ cached = nsm_lookup_addr(sap);
+
+ if (cached) {
+ atomic_inc(&cached->sm_count);
+ spin_unlock(&nsm_lock);
+ kfree(new);
+ dprintk("lockd: found nsm_handle for %s (%s), "
+ "cnt %d\n", cached->sm_name,
+ cached->sm_addrbuf,
+ atomic_read(&cached->sm_count));
+ return cached;
+ } else if (new) {
+ list_add(&new->sm_link, &nsm_handles);
+ spin_unlock(&nsm_lock);
+ dprintk("lockd: created nsm_handle for %s (%s)\n",
+ new->sm_name, new->sm_addrbuf);
+ return new;
+ }
- if (nsm) {
- list_add(&nsm->sm_link, &nsm_handles);
spin_unlock(&nsm_lock);
- dprintk("lockd: created nsm_handle for %s (%s)\n",
- nsm->sm_name, nsm->sm_addrbuf);
- return nsm;
- }
- spin_unlock(&nsm_lock);
+ new = nsm_init_handle(sap, salen, hostname, hostname_len);
+ } while (new);
- nsm = nsm_init_handle(sap, salen, hostname, hostname_len);
- if (nsm == NULL)
- return NULL;
- goto retry;
+ return NULL;
}
/**
--
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