Re: [Linux-nvdimm] [PATCH v2 10/20] pmem: use ida

From: Toshi Kani
Date: Wed Apr 29 2015 - 14:44:39 EST

Hi Dan,

Thanks for the update. This version of the patchset enumerates our NFIT
table properly. :-)

On Tue, 2015-04-28 at 14:25 -0400, Dan Williams wrote:
> In preparation for the pmem driver attaching to pmem-namespaces emitted
> by libnd, convert it to use an ida instead of an always increasing
> atomic index. This provides a bit of stability to pmem device names in
> the presence of driver re-bind events.
> @@ -122,20 +123,26 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
> {
> struct pmem_device *pmem;
> struct gendisk *disk;
> - int idx, err;
> + int err;
> err = -ENOMEM;
> pmem = kzalloc(sizeof(*pmem), GFP_KERNEL);
> if (!pmem)
> goto out;
> + pmem->id = ida_simple_get(&pmem_ida, 0, 0, GFP_KERNEL);

nd_pmem_probe() is called asynchronously via async_schedule_domain
(). We have seen a case that the region#->pmem# binding becomes
inconsistent across a reboot when there are 8 NVDIMM cards (reported by
Robert Elliott). This leads user to access a wrong device.

I think pmem id needs to be assigned before async_schedule_domain(), and
cascaded to nd_pmem_probe().


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at