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().
Only compile tested.
v2: The v1 conversion of ipcget_public() was incorrect. As
idr_pre_get() returns 0 for -ENOMEM failure, @err should have been
initialized to 1 not 0. As the function doesn't do preloading
itself anymore, there's no point in the error handling path.
Simply remove the -ENOMEM path.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Sedat Dilek <sedat.dilek@xxxxxxxxx>
Cc: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
---
Yeah, I messed up the ipcget_public() conversion. Can you please test
this one?
Thanks.
ipc/util.c | 30 +++++++++---------------------
1 file changed, 9 insertions(+), 21 deletions(-)
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -252,7 +252,7 @@ int ipc_addid(struct ipc_ids* ids, struc
{
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, struc
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_namespa
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_name
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 @@ retry:
/* 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 @@ retry:
}
up_write(&ids->rw_mutex);
- if (err == -EAGAIN)
- goto retry;
-
return err;
}
--
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