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

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>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 62 insertions, 69 deletions

diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 3127ae9e435c..7209712f3832 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -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_grant_ops;
 /*
  * 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 *block)
 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 *cookie,  struct sockaddr_in *sin)
 {
         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 *rqstp, struct nlm_file *file,
         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 *rqstp, struct nlm_file *file,
         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 kref *kref)
 {
         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_host *host, struct nlm_file *file)
         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 *file, struct nlm_lock *lock)
 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 *rqstp, struct nlm_cookie *cookie, u32 status
 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 --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index c8308bccd319..a92fc5813144 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -107,6 +107,7 @@ nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
         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, struct nlm_file *file, int action)
 {
         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, int action)
                         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 --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index c8635d84d5d2..2e740f6a2f77 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -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 */
 };