On Tue, 2015-10-27 at 10:46 -0500, Nathan Fontenot wrote:
> Commit a030e1e4bbd085bbcfd0a23f8d355fcd41f39bed make a change to use
> kstrndup() instead of kmalloc() + strlcpy() in the
> pseries_of_derive_parent()
> routine that introduces a subtle change in the parent path name
> generated.
> The kstrndup() routine will copy n characters followed by a
> terminating null,
> whereas strlcpy() will copy n-1 characters and add a terminating
> null.
>
> This slight difference results in having a parent path that includes
> the
> tailing '/' character, "/cpus/" vs. "/cpus". This then causes the
> subsequent
> call to of_find_node_by_path() to fail, and in the case of DLPAR add
> operations the DLPAR request fails.
>
> This patch decrements the pointer returned from kbasename() to point
> to the
> '/' character before the base name instead of the base name. This
> then
> adjusts the string length calculations to not include the trailing
> '/'
> in the parent path name.
>
> Signed-off-by: Nathan Fontenot <nf...@linux.vnet.ibm.com>
Reviewed-by: Andy Shevchenko <andriy.shevche...@linux.intel.com>
> ---
>
> Updates for v2: Decrement the pointer returned from kbasename()
> instead
> of subtracting 1 when calculating the string length.
>
> arch/powerpc/platforms/pseries/of_helpers.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/of_helpers.c
> b/arch/powerpc/platforms/pseries/of_helpers.c
> index 4417afe..2798933 100644
> --- a/arch/powerpc/platforms/pseries/of_helpers.c
> +++ b/arch/powerpc/platforms/pseries/of_helpers.c
> @@ -17,13 +17,16 @@ struct device_node
> *pseries_of_derive_parent(const char *path)
> {
> struct device_node *parent;
> char *parent_path = "/";
> - const char *tail = kbasename(path);
> + const char *tail;
> +
> + /* We do not want the trailing '/' character */
> + tail = kbasename(path) - 1;
>
> /* reject if path is "/" */
> if (!strcmp(path, "/"))
> return ERR_PTR(-EINVAL);
>
> - if (tail > path + 1) {
> + if (tail > path) {
> parent_path = kstrndup(path, tail - path,
> GFP_KERNEL);
> if (!parent_path)
> return ERR_PTR(-ENOMEM);
>
--
Andy Shevchenko <andriy.shevche...@linux.intel.com>
Intel Finland Oy
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