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clk: fix parent validation in __clk_set_parent() 

The below commit introduced a bug in __clk_set_parent()
which could cause it to *skip* the parent validation
which makes sure the parent passed to the api is a valid
one.

    commit 7975059db5
    Author: Rajendra Nayak <rnayak@ti.com>
    Date:   Wed Jun 6 14:41:31 2012 +0530

        clk: Allow late cache allocation for clk->parents

This was identified by the following compiler warning..

    drivers/clk/clk.c: In function '__clk_set_parent':
    drivers/clk/clk.c:1083:5: warning: 'i' may be used uninitialized in this function [-Wuninitialized]

.. as reported by Marc Kleine-Budde.

There were various options discussed on how to fix this, one
being initing 'i' to clk->num_parents, but the below approach
was found to be more appropriate as it also makes the 'parent
validation' code simpler to read.

Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: stable@kernel.org
This commit is contained in:
Rajendra Nayak 2012-07-03 12:11:41 +05:30 committed by Mike Turquette
parent 6887a4131d
commit 863b13271f
1 changed files with 13 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/clk/clk.c
View File

@ -1067,26 +1067,24 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
old_parent = clk->parent;
/* find index of new parent clock using cached parent ptrs */
if (clk->parents)
for (i = 0; i < clk->num_parents; i++)
if (clk->parents[i] == parent)
break;
else
if (!clk->parents)
clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
GFP_KERNEL);
/*
* find index of new parent clock using string name comparison
* also try to cache the parent to avoid future calls to __clk_lookup
* find index of new parent clock using cached parent ptrs,
* or if not yet cached, use string name comparison and cache
* them now to avoid future calls to __clk_lookup.
*/
if (i == clk->num_parents)
for (i = 0; i < clk->num_parents; i++)
if (!strcmp(clk->parent_names[i], parent->name)) {
if (clk->parents)
clk->parents[i] = __clk_lookup(parent->name);
break;
}
for (i = 0; i < clk->num_parents; i++) {
if (clk->parents && clk->parents[i] == parent)
break;
else if (!strcmp(clk->parent_names[i], parent->name)) {
if (clk->parents)
clk->parents[i] = __clk_lookup(parent->name);
break;
}
}
if (i == clk->num_parents) {
pr_debug("%s: clock %s is not a possible parent of clock %s\n",