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CIFS: Do not kmalloc under the flocks spinlock 

Reorganize the code to make the memory already allocated before
spinlock'ed loop.

Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This commit is contained in:
Pavel Shilovsky 2012-03-05 09:39:20 +03:00 committed by Steve French
parent b0f8ef202e
commit d5751469f2
1 changed files with 58 additions and 15 deletions
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73
fs/cifs/file.c
View File

@ -920,16 +920,26 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
for (lockp = &inode->i_flock; *lockp != NULL; \
lockp = &(*lockp)->fl_next)
struct lock_to_push {
struct list_head llist;
__u64 offset;
__u64 length;
__u32 pid;
__u16 netfid;
__u8 type;
};
static int
cifs_push_posix_locks(struct cifsFileInfo *cfile)
{
struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct file_lock *flock, **before;
struct cifsLockInfo *lck, *tmp;
unsigned int count = 0, i = 0;
int rc = 0, xid, type;
struct list_head locks_to_send, *el;
struct lock_to_push *lck, *tmp;
__u64 length;
struct list_head locks_to_send;
xid = GetXid();
@ -940,29 +950,55 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
return rc;
}
INIT_LIST_HEAD(&locks_to_send);
lock_flocks();
cifs_for_each_lock(cfile->dentry->d_inode, before) {
if ((*before)->fl_flags & FL_POSIX)
count++;
}
unlock_flocks();
INIT_LIST_HEAD(&locks_to_send);
/*
* Allocating count locks is enough because no locks can be added to
* the list while we are holding cinode->lock_mutex that protects
* locking operations of this inode.
*/
for (; i < count; i++) {
lck = kmalloc(sizeof(struct lock_to_push), GFP_KERNEL);
if (!lck) {
rc = -ENOMEM;
goto err_out;
}
list_add_tail(&lck->llist, &locks_to_send);
}
i = 0;
el = locks_to_send.next;
lock_flocks();
cifs_for_each_lock(cfile->dentry->d_inode, before) {
if (el == &locks_to_send) {
/* something is really wrong */
cERROR(1, "Can't push all brlocks!");
break;
}
flock = *before;
if ((flock->fl_flags & FL_POSIX) == 0)
continue;
length = 1 + flock->fl_end - flock->fl_start;
if (flock->fl_type == F_RDLCK || flock->fl_type == F_SHLCK)
type = CIFS_RDLCK;
else
type = CIFS_WRLCK;
lck = cifs_lock_init(flock->fl_start, length, type,
cfile->netfid);
if (!lck) {
rc = -ENOMEM;
goto send_locks;
}
lck = list_entry(el, struct lock_to_push, llist);
lck->pid = flock->fl_pid;
list_add_tail(&lck->llist, &locks_to_send);
lck->netfid = cfile->netfid;
lck->length = length;
lck->type = type;
lck->offset = flock->fl_start;
i++;
el = el->next;
}
send_locks:
unlock_flocks();
list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
@ -979,11 +1015,18 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile)
kfree(lck);
}
out:
cinode->can_cache_brlcks = false;
mutex_unlock(&cinode->lock_mutex);
FreeXid(xid);
return rc;
err_out:
list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
list_del(&lck->llist);
kfree(lck);
}
goto out;
}
static int