[PATCH 009 of 19] knfsd: lockd: Change list of blocked list to list_node

NeilBrown
2006-09-01T04:40:12Z

From: Olaf Kirch <okir@suse.de>

This patch changes the nlm_blocked list to use a list_node
instead of homegrown linked list handling.

Signed-off-by: Olaf Kirch <okir@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
./fs/lockd/svclock.c | 119 +++++++++++++++++++-----------------------
./fs/lockd/svcsubs.c | 5 +
./include/linux/lockd/lockd.h | 7 +-
3 files changed, 62 insertions(+), 69 deletions(-)

diff .prev/fs/lockd/svclock.c ./fs/lockd/svclock.c
--- .prev/fs/lockd/svclock.c 2006-09-01 10:42:31.000000000 +1000
+++ ./fs/lockd/svclock.c 2006-09-01 10:44:39.000000000 +1000
@@ -40,7 +40,7 @@

static void nlmsvc_release_block(struct nlm_block *block);
static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
-static int nlmsvc_remove_block(struct nlm_block *block);
+static void nlmsvc_remove_block(struct nlm_block *block);

static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
static void nlmsvc_freegrantargs(struct nlm_rqst *call);
@@ -49,7 +49,7 @@ static const struct rpc_call_ops nlmsvc_
/*
* The list of blocked locks to retry
*/
-static struct nlm_block * nlm_blocked;
+static LIST_HEAD(nlm_blocked);

/*
* Insert a blocked lock into the global list
@@ -57,48 +57,44 @@ static struct nlm_block * nlm_blocked;
static void
nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
{
- struct nlm_block **bp, *b;
+ struct nlm_block *b;
+ struct list_head *pos;

dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
- kref_get(&block->b_count);
- if (block->b_queued)
- nlmsvc_remove_block(block);
- bp = &nlm_blocked;
+ if (list_empty(&block->b_list)) {
+ kref_get(&block->b_count);
+ } else {
+ list_del_init(&block->b_list);
+ }
+
+ pos = &nlm_blocked;
if (when != NLM_NEVER) {
if ((when += jiffies) == NLM_NEVER)
when ++;
- while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER)
- bp = &b->b_next;
- } else
- while ((b = *bp) != 0)
- bp = &b->b_next;
+ list_for_each(pos, &nlm_blocked) {
+ b = list_entry(pos, struct nlm_block, b_list);
+ if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
+ break;
+ }
+ /* On normal exit from the loop, pos == &nlm_blocked,
+ * so we will be adding to the end of the list - good
+ */
+ }

- block->b_queued = 1;
+ list_add_tail(&block->b_list, pos);
block->b_when = when;
- block->b_next = b;
- *bp = block;
}

/*
* Remove a block from the global list
*/
-static int
+static inline void
nlmsvc_remove_block(struct nlm_block *block)
{
- struct nlm_block **bp, *b;
-
- if (!block->b_queued)
- return 1;
- for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) {
- if (b == block) {
- *bp = block->b_next;
- block->b_queued = 0;
- nlmsvc_release_block(block);
- return 1;
- }
+ if (!list_empty(&block->b_list)) {
+ list_del_init(&block->b_list);
+ nlmsvc_release_block(block);
}
-
- return 0;
}

/*
@@ -107,14 +103,14 @@ nlmsvc_remove_block(struct nlm_block *bl
static struct nlm_block *
nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
{
- struct nlm_block **head, *block;
+ struct nlm_block *block;
struct file_lock *fl;

dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
file, lock->fl.fl_pid,
(long long)lock->fl.fl_start,
(long long)lock->fl.fl_end, lock->fl.fl_type);
- for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) {
+ list_for_each_entry(block, &nlm_blocked, b_list) {
fl = &block->b_call->a_args.lock.fl;
dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
block->b_file, fl->fl_pid,
@@ -147,16 +143,16 @@ nlmsvc_find_block(struct nlm_cookie *coo
{
struct nlm_block *block;

- for (block = nlm_blocked; block; block = block->b_next) {
- dprintk("cookie: head of blocked queue %p, block %p\n",
- nlm_blocked, block);
+ list_for_each_entry(block, &nlm_blocked, b_list) {
if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)
&& nlm_cmp_addr(sin, &block->b_host->h_addr))
- break;
+ goto found;
}

- if (block != NULL)
- kref_get(&block->b_count);
+ return NULL;
+
+found:
+ kref_get(&block->b_count);
return block;
}

@@ -192,6 +188,8 @@ nlmsvc_create_block(struct svc_rqst *rqs
if (block == NULL)
goto failed;
kref_init(&block->b_count);
+ INIT_LIST_HEAD(&block->b_list);
+ INIT_LIST_HEAD(&block->b_flist);

if (!nlmsvc_setgrantargs(call, lock))
goto failed_free;
@@ -210,8 +208,7 @@ nlmsvc_create_block(struct svc_rqst *rqs
file->f_count++;

/* Add to file's list of blocks */
- block->b_fnext = file->f_blocks;
- file->f_blocks = block;
+ list_add(&block->b_flist, &file->f_blocks);

/* Set up RPC arguments for callback */
block->b_call = call;
@@ -248,18 +245,12 @@ static void nlmsvc_free_block(struct kre
{
struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
struct nlm_file *file = block->b_file;
- struct nlm_block **bp;

dprintk("lockd: freeing block %p...\n", block);

- down(&file->f_sema);
/* Remove block from file's list of blocks */
- for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) {
- if (*bp == block) {
- *bp = block->b_fnext;
- break;
- }
- }
+ down(&file->f_sema);
+ list_del_init(&block->b_flist);
up(&file->f_sema);

nlmsvc_freegrantargs(block->b_call);
@@ -279,21 +270,23 @@ static void nlmsvc_act_mark(struct nlm_h
struct nlm_block *block;

down(&file->f_sema);
- for (block = file->f_blocks; block != NULL; block = block->b_fnext)
+ list_for_each_entry(block, &file->f_blocks, b_flist)
block->b_host->h_inuse = 1;
up(&file->f_sema);
}

static void nlmsvc_act_unlock(struct nlm_host *host, struct nlm_file *file)
{
- struct nlm_block *block;
+ struct nlm_block *block, *next;

restart:
down(&file->f_sema);
- for (block = file->f_blocks; block != NULL; block = block->b_fnext) {
+ list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
if (host != NULL && host != block->b_host)
continue;
- if (!block->b_queued)
+ /* Do not destroy blocks that are not on
+ * the global retry list - why? */
+ if (list_empty(&block->b_list))
continue;
kref_get(&block->b_count);
up(&file->f_sema);
@@ -528,10 +521,10 @@ nlmsvc_cancel_blocked(struct nlm_file *f
static void
nlmsvc_notify_blocked(struct file_lock *fl)
{
- struct nlm_block **bp, *block;
+ struct nlm_block *block;

dprintk("lockd: VFS unblock notification for block %p\n", fl);
- for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) {
+ list_for_each_entry(block, &nlm_blocked, b_list) {
if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
nlmsvc_insert_block(block, 0);
svc_wake_up(block->b_daemon);
@@ -697,16 +690,19 @@ nlmsvc_grant_reply(struct svc_rqst *rqst
unsigned long
nlmsvc_retry_blocked(void)
{
- struct nlm_block *block;
+ unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
+ struct nlm_block *block;
+
+ while (!list_empty(&nlm_blocked)) {
+ block = list_entry(nlm_blocked.next, struct nlm_block, b_list);

- dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
- nlm_blocked,
- nlm_blocked? nlm_blocked->b_when : 0);
- while ((block = nlm_blocked) != 0) {
if (block->b_when == NLM_NEVER)
break;
- if (time_after(block->b_when,jiffies))
+ if (time_after(block->b_when,jiffies)) {
+ timeout = block->b_when - jiffies;
break;
+ }
+
dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
block, block->b_when);
kref_get(&block->b_count);
@@ -714,8 +710,5 @@ nlmsvc_retry_blocked(void)
nlmsvc_release_block(block);
}

- if ((block = nlm_blocked) && block->b_when != NLM_NEVER)
- return (block->b_when - jiffies);
-
- return MAX_SCHEDULE_TIMEOUT;
+ return timeout;
}

diff .prev/fs/lockd/svcsubs.c ./fs/lockd/svcsubs.c
--- .prev/fs/lockd/svcsubs.c 2006-09-01 10:42:31.000000000 +1000
+++ ./fs/lockd/svcsubs.c 2006-09-01 10:42:51.000000000 +1000
@@ -107,6 +107,7 @@ nlm_lookup_file(struct svc_rqst *rqstp,
memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
file->f_hash = hash;
init_MUTEX(&file->f_sema);
+ INIT_LIST_HEAD(&file->f_blocks);

/* Open the file. Note that this must not sleep for too long, else
* we would lock up lockd:-) So no NFS re-exports, folks.
@@ -220,7 +221,7 @@ nlm_inspect_file(struct nlm_host *host,
{
if (action == NLM_ACT_CHECK) {
/* Fast path for mark and sweep garbage collection */
- if (file->f_count || file->f_blocks || file->f_shares)
+ if (file->f_count || list_empty(&file->f_blocks) || file->f_shares)
return 1;
} else {
nlmsvc_traverse_blocks(host, file, action);
@@ -253,7 +254,7 @@ nlm_traverse_files(struct nlm_host *host
mutex_lock(&nlm_file_mutex);
file->f_count--;
/* No more references to this file. Let go of it. */
- if (!file->f_blocks && !file->f_locks
+ if (list_empty(&file->f_blocks) && !file->f_locks
&& !file->f_shares && !file->f_count) {
*fp = file->f_next;
nlmsvc_ops->fclose(file->f_file);

diff .prev/include/linux/lockd/lockd.h ./include/linux/lockd/lockd.h
--- .prev/include/linux/lockd/lockd.h 2006-09-01 10:42:31.000000000 +1000
+++ ./include/linux/lockd/lockd.h 2006-09-01 10:42:51.000000000 +1000
@@ -109,7 +109,7 @@ struct nlm_file {
struct nfs_fh f_handle; /* NFS file handle */
struct file * f_file; /* VFS file pointer */
struct nlm_share * f_shares; /* DOS shares */
- struct nlm_block * f_blocks; /* blocked locks */
+ struct list_head f_blocks; /* blocked locks */
unsigned int f_locks; /* guesstimate # of locks */
unsigned int f_count; /* reference count */
struct semaphore f_sema; /* avoid concurrent access */
@@ -123,14 +123,13 @@ struct nlm_file {
#define NLM_NEVER (~(unsigned long) 0)
struct nlm_block {
struct kref b_count; /* Reference count */
- struct nlm_block * b_next; /* linked list (all blocks) */
- struct nlm_block * b_fnext; /* linked list (per file) */
+ struct list_head b_list; /* linked list of all blocks */
+ struct list_head b_flist; /* linked list (per file) */
struct nlm_rqst * b_call; /* RPC args & callback info */
struct svc_serv * b_daemon; /* NLM service */
struct nlm_host * b_host; /* host handle for RPC clnt */
unsigned long b_when; /* next re-xmit */
unsigned int b_id; /* block id */
- unsigned char b_queued; /* re-queued */
unsigned char b_granted; /* VFS granted lock */
struct nlm_file * b_file; /* file in question */
};