RE: [PATCH v3 14/21] libnd: blk labels and namespace instantiation

From: Elliott, Robert (Server Storage)
Date: Fri May 22 2015 - 14:38:56 EST



> -----Original Message-----
> From: Linux-nvdimm [mailto:linux-nvdimm-bounces@xxxxxxxxxxxx] On Behalf Of
> Dan Williams
> Sent: Wednesday, May 20, 2015 3:57 PM
> To: axboe@xxxxxxxxx
> Cc: linux-nvdimm@xxxxxxxxxxxx; neilb@xxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; hch@xxxxxx; linux-acpi@xxxxxxxxxxxxxxx;
> mingo@xxxxxxxxxx
> Subject: [PATCH v3 14/21] libnd: blk labels and namespace instantiation
>
...
> @@ -1029,6 +1244,173 @@ static struct device **create_namespace_pmem(struct
> nd_region *nd_region)
> return NULL;
> }
>
> +struct resource *nsblk_add_resource(struct nd_region *nd_region,
> + struct nd_dimm_drvdata *ndd, struct nd_namespace_blk *nsblk,
> + resource_size_t start)
> +{
> + struct nd_label_id label_id;
> + struct resource *res;
> +
> + nd_label_gen_id(&label_id, nsblk->uuid, NSLABEL_FLAG_LOCAL);
> + nsblk->res = krealloc(nsblk->res,
> + sizeof(void *) * (nsblk->num_resources + 1),
> + GFP_KERNEL);
> + if (!nsblk->res)
> + return NULL;

scripts/checkpatch.pl doesn't like that:
WARNING: Reusing the krealloc arg is almost always a bug
#1411: FILE: drivers/block/nd/namespace_devs.c:1411:
+ nsblk->res = krealloc(nsblk->res,

The reasoning (https://lkml.org/lkml/2013/3/14/558) is:

"If krealloc() returns NULL, it *doesn't* free the original. So any
code of the form 'foo = krealloc(foo, …);' is almost certainly a bug."


---
Robert Elliott, HP Server Storage
--
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