cifs: convert cifsFileInfo->count to non-atomic counter
The count for cifsFileInfo is currently an atomic, but that just adds
complexity for little value. We generally need to hold cifs_file_list_lock
to traverse the lists anyway so we might as well make this counter
non-atomic and simply use the cifs_file_list_lock to protect it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 3365e77f..6319db0 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -395,16 +395,19 @@
struct list_head llist; /* list of byte range locks we have. */
bool invalidHandle:1; /* file closed via session abend */
bool oplock_break_cancelled:1;
- atomic_t count; /* reference count */
+ int count; /* refcount -- protected by cifs_file_list_lock */
struct mutex fh_mutex; /* prevents reopen race after dead ses*/
struct cifs_search_info srch_inf;
struct work_struct oplock_break; /* work for oplock breaks */
};
-/* Take a reference on the file private data */
+/*
+ * Take a reference on the file private data. Must be called with
+ * cifs_file_list_lock held.
+ */
static inline void cifsFileInfo_get(struct cifsFileInfo *cifs_file)
{
- atomic_inc(&cifs_file->count);
+ ++cifs_file->count;
}
void cifsFileInfo_put(struct cifsFileInfo *cifs_file);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8c81e7b..baf4b506 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -232,6 +232,7 @@
if (pCifsFile == NULL)
return pCifsFile;
+ pCifsFile->count = 1;
pCifsFile->netfid = fileHandle;
pCifsFile->pid = current->tgid;
pCifsFile->uid = current_fsuid();
@@ -242,7 +243,6 @@
mutex_init(&pCifsFile->fh_mutex);
mutex_init(&pCifsFile->lock_mutex);
INIT_LIST_HEAD(&pCifsFile->llist);
- atomic_set(&pCifsFile->count, 1);
INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
spin_lock(&cifs_file_list_lock);
@@ -267,7 +267,8 @@
/*
* Release a reference on the file private data. This may involve closing
- * the filehandle out on the server.
+ * the filehandle out on the server. Must be called without holding
+ * cifs_file_list_lock.
*/
void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
{
@@ -276,7 +277,7 @@
struct cifsLockInfo *li, *tmp;
spin_lock(&cifs_file_list_lock);
- if (!atomic_dec_and_test(&cifs_file->count)) {
+ if (--cifs_file->count > 0) {
spin_unlock(&cifs_file_list_lock);
return;
}
@@ -2322,6 +2323,7 @@
cifs_oplock_break_put(cfile);
}
+/* must be called while holding cifs_file_list_lock */
void cifs_oplock_break_get(struct cifsFileInfo *cfile)
{
cifs_sb_active(cfile->dentry->d_sb);