On Wed, 6 May 2020 09:25:54 +0300 Vasily Averin <[email protected]> wrote:
> new_pos should jump through hole of unused ids, > pos can be updated inside "for" cycle. > > Cc: [email protected] > Fixes: 89163f93c6f9 ("ipc/util.c: sysvipc_find_ipc() should increase position > index") This: > --- a/ipc/util.c > +++ b/ipc/util.c > @@ -764,21 +764,21 @@ static struct kern_ipc_perm *sysvipc_find_ipc(struct > ipc_ids *ids, loff_t pos, > total++; > } > > - *new_pos = pos + 1; > + ipc = NULL; > if (total >= ids->in_use) > - return NULL; > + goto out; > > for (; pos < ipc_mni; pos++) { > ipc = idr_find(&ids->ipcs_idr, pos); > if (ipc != NULL) { > rcu_read_lock(); > ipc_lock_object(ipc); > - return ipc; > + break; > } > } > - > - /* Out of range - return NULL to terminate iteration */ > - return NULL; > +out: > + *new_pos = pos + 1; > + return ipc; > } > > static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) Messes up Matthew's "ipc: convert ipcs_idr to XArray" (http://lkml.kernel.org/r/[email protected]). Here's how I resolved things. Please check? static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, loff_t *new_pos) { unsigned long index = pos; struct kern_ipc_perm *ipc; rcu_read_lock(); ipc = xa_find(&ids->ipcs, &index, ULONG_MAX, XA_PRESENT); if (ipc) ipc_lock_object(ipc); else rcu_read_unlock(); *new_pos = pos + 1; return ipc; }
