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cifs: convert cifsFileInfo->count to non-atomic counter

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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>
This commit is contained in:
Jeff Layton 2010-10-15 15:34:06 -04:00 committed by Steve French
parent 229aebb873
commit 5f6dbc9e4a
2 changed files with 11 additions and 6 deletions
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9
fs/cifs/cifsglob.h
View File

@ -395,16 +395,19 @@ struct cifsFileInfo {
struct list_head llist; /* list of byte range locks we have. */ struct list_head llist; /* list of byte range locks we have. */
bool invalidHandle:1; /* file closed via session abend */ bool invalidHandle:1; /* file closed via session abend */
bool oplock_break_cancelled:1; 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 mutex fh_mutex; /* prevents reopen race after dead ses*/
struct cifs_search_info srch_inf; struct cifs_search_info srch_inf;
struct work_struct oplock_break; /* work for oplock breaks */ 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) static inline void cifsFileInfo_get(struct cifsFileInfo *cifs_file)
{ {
atomic_inc(&cifs_file->count); ++cifs_file->count;
} }
void cifsFileInfo_put(struct cifsFileInfo *cifs_file); void cifsFileInfo_put(struct cifsFileInfo *cifs_file);

8
fs/cifs/file.c
View File

@ -232,6 +232,7 @@ cifs_new_fileinfo(__u16 fileHandle, struct file *file,
if (pCifsFile == NULL) if (pCifsFile == NULL)
return pCifsFile; return pCifsFile;
pCifsFile->count = 1;
pCifsFile->netfid = fileHandle; pCifsFile->netfid = fileHandle;
pCifsFile->pid = current->tgid; pCifsFile->pid = current->tgid;
pCifsFile->uid = current_fsuid(); pCifsFile->uid = current_fsuid();
@ -242,7 +243,6 @@ cifs_new_fileinfo(__u16 fileHandle, struct file *file,
mutex_init(&pCifsFile->fh_mutex); mutex_init(&pCifsFile->fh_mutex);
mutex_init(&pCifsFile->lock_mutex); mutex_init(&pCifsFile->lock_mutex);
INIT_LIST_HEAD(&pCifsFile->llist); INIT_LIST_HEAD(&pCifsFile->llist);
atomic_set(&pCifsFile->count, 1);
INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break); INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);
spin_lock(&cifs_file_list_lock); spin_lock(&cifs_file_list_lock);
@ -267,7 +267,8 @@ cifs_new_fileinfo(__u16 fileHandle, struct file *file,
/* /*
* Release a reference on the file private data. This may involve closing * 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) void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
{ {
@ -276,7 +277,7 @@ void cifsFileInfo_put(struct cifsFileInfo *cifs_file)
struct cifsLockInfo *li, *tmp; struct cifsLockInfo *li, *tmp;
spin_lock(&cifs_file_list_lock); 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); spin_unlock(&cifs_file_list_lock);
return; return;
} }
@ -2322,6 +2323,7 @@ void cifs_oplock_break(struct work_struct *work)
cifs_oplock_break_put(cfile); cifs_oplock_break_put(cfile);
} }
/* must be called while holding cifs_file_list_lock */
void cifs_oplock_break_get(struct cifsFileInfo *cfile) void cifs_oplock_break_get(struct cifsFileInfo *cfile)
{ {
cifs_sb_active(cfile->dentry->d_sb); cifs_sb_active(cfile->dentry->d_sb);