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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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f755ecfb8c
Commit a030e1e4bb 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 <nfont@linux.vnet.ibm.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
39 lines
976 B
C
39 lines
976 B
C
#include <linux/string.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include "of_helpers.h"
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/**
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* pseries_of_derive_parent - basically like dirname(1)
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* @path: the full_name of a node to be added to the tree
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*
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* Returns the node which should be the parent of the node
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* described by path. E.g., for path = "/foo/bar", returns
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* the node with full_name = "/foo".
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*/
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struct device_node *pseries_of_derive_parent(const char *path)
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{
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struct device_node *parent;
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char *parent_path = "/";
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const char *tail;
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/* We do not want the trailing '/' character */
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tail = kbasename(path) - 1;
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/* reject if path is "/" */
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if (!strcmp(path, "/"))
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return ERR_PTR(-EINVAL);
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if (tail > path) {
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parent_path = kstrndup(path, tail - path, GFP_KERNEL);
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if (!parent_path)
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return ERR_PTR(-ENOMEM);
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}
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parent = of_find_node_by_path(parent_path);
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if (strcmp(parent_path, "/"))
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kfree(parent_path);
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return parent ? parent : ERR_PTR(-EINVAL);
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}
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