On 02/11/18 22:27, frowand.list@xxxxxxxxx wrote:
> From: Frank Rowand <frank.rowand@xxxxxxxx>
>
> Create a cache of the nodes that contain a phandle property. Use this
> cache to find the node for a given phandle value instead of scanning
> the devicetree to find the node. If the phandle value is not found
> in the cache, of_find_node_by_phandle() will fall back to the tree
> scan algorithm.
>
> The cache is initialized in of_core_init().
>
> The cache is freed via a late_initcall_sync() if modules are not
> enabled.
>
> Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxx>
> ---
>
> Changes since v1:
> - change short description from
> of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
> - rebase on v4.16-rc1
> - reorder new functions in base.c to avoid forward declaration
> - add locking around kfree(phandle_cache) for memory ordering
> - add explicit check for non-null of phandle_cache in
> of_find_node_by_phandle(). There is already a check for !handle,
> which prevents accessing a null phandle_cache, but that dependency
> is not obvious, so this check makes it more apparent.
> - do not free phandle_cache if modules are enabled, so that
> cached phandles will be available when modules are loaded
>
> drivers/of/base.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++---
> drivers/of/of_private.h | 5 +++
> drivers/of/resolver.c | 21 -----------
> 3 files changed, 94 insertions(+), 25 deletions(-)
>
< snip >
Hi Chintan,
Just as in the previous version, this part of the patch will not apply
on older kernel versions, and can just be deleted:
> diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
> index 740d19bde601..a7580c24737a 100644
> --- a/drivers/of/resolver.c
> +++ b/drivers/of/resolver.c
> @@ -19,27 +19,6 @@
>
> #include "of_private.h"
>
> -/* illegal phandle value (set when unresolved) */
> -#define OF_PHANDLE_ILLEGAL 0xdeadbeef
> -
> -static phandle live_tree_max_phandle(void)
> -{
> - struct device_node *node;
> - phandle phandle;
> - unsigned long flags;
> -
> - raw_spin_lock_irqsave(&devtree_lock, flags);
> - phandle = 0;
> - for_each_of_allnodes(node) {
> - if (node->phandle != OF_PHANDLE_ILLEGAL &&
> - node->phandle > phandle)
> - phandle = node->phandle;
> - }
> - raw_spin_unlock_irqrestore(&devtree_lock, flags);
> -
> - return phandle;
> -}
> -
> static void adjust_overlay_phandles(struct device_node *overlay,
> int phandle_delta)
> {
>
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