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Commit 54924ea3 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

ipc: convert to idr_alloc() 



Convert to the much saner new idr interface.

The new interface doesn't directly translate to the way idr_pre_get()
was used around ipc_addid() as preloading disables preemption.  From
my cursory reading, it seems like we should be able to do all
allocation from ipc_addid(), so I moved it there.  Can you please
check whether this would be okay?  If this is wrong and ipc_addid()
should be allowed to be called from non-sleepable context, I'd suggest
allocating id itself in the outer functions and later install the
pointer using idr_replace().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Reported-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
Tested-by: default avatarSedat Dilek <sedat.dilek@gmail.com>
Cc: Stanislav Kinsbursky <skinsbursky@parallels.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6b207ba3

ipc/util.c

+9 −21
Original line number Diff line number Diff line
@@ -252,7 +252,7 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) 
{

	kuid_t euid;

	kgid_t egid;

	int id, err;

	int id;

	int next_id = ids->next_id;



	if (size > IPCMNI)
@@ -261,17 +261,21 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) 
	if (ids->in_use >= size)

		return -ENOSPC;



	idr_preload(GFP_KERNEL);



	spin_lock_init(&new->lock);

	new->deleted = 0;

	rcu_read_lock();

	spin_lock(&new->lock);



	err = idr_get_new_above(&ids->ipcs_idr, new,

				(next_id < 0) ? 0 : ipcid_to_idx(next_id), &id);

	if (err) {

	id = idr_alloc(&ids->ipcs_idr, new,

		       (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,

		       GFP_NOWAIT);

	idr_preload_end();

	if (id < 0) {

		spin_unlock(&new->lock);

		rcu_read_unlock();

		return err;

		return id;

	}



	ids->in_use++;
@@ -307,19 +311,10 @@ static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, 
		struct ipc_ops *ops, struct ipc_params *params)

{

	int err;

retry:

	err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);



	if (!err)

		return -ENOMEM;



	down_write(&ids->rw_mutex);

	err = ops->getnew(ns, params);

	up_write(&ids->rw_mutex);



	if (err == -EAGAIN)

		goto retry;



	return err;

}
@@ -376,8 +371,6 @@ static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, 
	struct kern_ipc_perm *ipcp;

	int flg = params->flg;

	int err;

retry:

	err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);



	/*

	 * Take the lock as a writer since we are potentially going to add
@@ -389,8 +382,6 @@ static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, 
		/* key not used */

		if (!(flg & IPC_CREAT))

			err = -ENOENT;

		else if (!err)

			err = -ENOMEM;

		else

			err = ops->getnew(ns, params);

	} else {
@@ -413,9 +404,6 @@ static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, 
	}

	up_write(&ids->rw_mutex);



	if (err == -EAGAIN)

		goto retry;



	return err;

}