[PATCH 010 of 19] knfsd: Change nlm_file to use a hlist

NeilBrown
2006-09-01T04:39:42Z

From: Olaf Kirch <okir@suse.de>

This changes struct nlm_file and the nlm_files hash table
to use a hlist instead of the home-grown lists.

This allows us to remove f_hash which was only used to find the right
hash chain to delete an entry from.

It also increases the size of the nlm_files hash table from
32 to 128.

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

### Diffstat output
./fs/lockd/svcsubs.c | 42 ++++++++++++++++--------------------------
./include/linux/lockd/lockd.h | 3 +--
2 files changed, 17 insertions(+), 28 deletions(-)

diff .prev/fs/lockd/svcsubs.c ./fs/lockd/svcsubs.c
--- .prev/fs/lockd/svcsubs.c 2006-09-01 10:42:51.000000000 +1000
+++ ./fs/lockd/svcsubs.c 2006-09-01 10:45:16.000000000 +1000
@@ -25,9 +25,9 @@
/*
* Global file hash table
*/
-#define FILE_HASH_BITS 5
+#define FILE_HASH_BITS 7
#define FILE_NRHASH (1<<FILE_HASH_BITS)
-static struct nlm_file * nlm_files[FILE_NRHASH];
+static struct hlist_head nlm_files[FILE_NRHASH];
static DEFINE_MUTEX(nlm_file_mutex);

#ifdef NFSD_DEBUG
@@ -82,6 +82,7 @@ u32
nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result,
struct nfs_fh *f)
{
+ struct hlist_node *pos;
struct nlm_file *file;
unsigned int hash;
u32 nfserr;
@@ -93,7 +94,7 @@ nlm_lookup_file(struct svc_rqst *rqstp,
/* Lock file table */
mutex_lock(&nlm_file_mutex);

- for (file = nlm_files[hash]; file; file = file->f_next)
+ hlist_for_each_entry(file, pos, &nlm_files[hash], f_list)
if (!nfs_compare_fh(&file->f_handle, f))
goto found;

@@ -105,8 +106,8 @@ nlm_lookup_file(struct svc_rqst *rqstp,
goto out_unlock;

memcpy(&file->f_handle, f, sizeof(struct nfs_fh));
- file->f_hash = hash;
init_MUTEX(&file->f_sema);
+ INIT_HLIST_NODE(&file->f_list);
INIT_LIST_HEAD(&file->f_blocks);

/* Open the file. Note that this must not sleep for too long, else
@@ -120,8 +121,7 @@ nlm_lookup_file(struct svc_rqst *rqstp,
goto out_free;
}

- file->f_next = nlm_files[hash];
- nlm_files[hash] = file;
+ hlist_add_head(&file->f_list, &nlm_files[hash]);

found:
dprintk("lockd: found file %p (count %d)\n", file, file->f_count);
@@ -150,22 +150,14 @@ out_free:
static inline void
nlm_delete_file(struct nlm_file *file)
{
- struct nlm_file **fp, *f;
-
nlm_debug_print_file("closing file", file);
-
- fp = nlm_files + file->f_hash;
- while ((f = *fp) != NULL) {
- if (f == file) {
- *fp = file->f_next;
- nlmsvc_ops->fclose(file->f_file);
- kfree(file);
- return;
- }
- fp = &f->f_next;
+ if (!hlist_unhashed(&file->f_list)) {
+ hlist_del(&file->f_list);
+ nlmsvc_ops->fclose(file->f_file);
+ kfree(file);
+ } else {
+ printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
}
-
- printk(KERN_WARNING "lockd: attempt to release unknown file!\n");
}

/*
@@ -236,13 +228,13 @@ nlm_inspect_file(struct nlm_host *host,
static int
nlm_traverse_files(struct nlm_host *host, int action)
{
- struct nlm_file *file, **fp;
+ struct hlist_node *pos, *next;
+ struct nlm_file *file;
int i, ret = 0;

mutex_lock(&nlm_file_mutex);
for (i = 0; i < FILE_NRHASH; i++) {
- fp = nlm_files + i;
- while ((file = *fp) != NULL) {
+ hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
file->f_count++;
mutex_unlock(&nlm_file_mutex);

@@ -256,11 +248,9 @@ nlm_traverse_files(struct nlm_host *host
/* No more references to this file. Let go of it. */
if (list_empty(&file->f_blocks) && !file->f_locks
&& !file->f_shares && !file->f_count) {
- *fp = file->f_next;
+ hlist_del(&file->f_list);
nlmsvc_ops->fclose(file->f_file);
kfree(file);
- } else {
- fp = &file->f_next;
}
}
}

diff .prev/include/linux/lockd/lockd.h ./include/linux/lockd/lockd.h
--- .prev/include/linux/lockd/lockd.h 2006-09-01 10:42:51.000000000 +1000
+++ ./include/linux/lockd/lockd.h 2006-09-01 10:45:16.000000000 +1000
@@ -105,7 +105,7 @@ struct nlm_rqst {
* an NFS client.
*/
struct nlm_file {
- struct nlm_file * f_next; /* linked list */
+ struct hlist_node f_list; /* linked list */
struct nfs_fh f_handle; /* NFS file handle */
struct file * f_file; /* VFS file pointer */
struct nlm_share * f_shares; /* DOS shares */
@@ -113,7 +113,6 @@ struct nlm_file {
unsigned int f_locks; /* guesstimate # of locks */
unsigned int f_count; /* reference count */
struct semaphore f_sema; /* avoid concurrent access */
- int f_hash; /* hash of f_handle */
};

/*