[linux-yocto] [PATCH 4.18-rt] of: phandle_cache merge fixup for preempt-rt
Bruce Ashfield
bruce.ashfield at gmail.com
Thu Mar 21 13:07:53 PDT 2019
Thanks Paul, this is now merged.
Bruce
On Thu, Mar 21, 2019 at 3:12 PM Paul Gortmaker
<paul.gortmaker at windriver.com> wrote:
>
> In yocto merge 5cc3fddf0e2a ("Merge branch 'v4.18/standard/base' into
> v4.18/standard/preempt-rt/base") there was a conflict between the
> backport of upstream b8a9ac1a5b99 ("of: of_node_get()/of_node_put() nodes
> held in phandle cache") and the rt-specific commit b75caf08b721 ("of:
> allocate / free phandle cache outside of the devtree_lock")
>
> Unfortunately the conflict resolution left a shadow variable introduced
> by the rt patch as undefined, resulting in:
>
> drivers/of/base.c:120:2: error: 'shadow' undeclared (first use in this function)
> shadow = phandle_cache;
> ^~~~~~
>
> drivers/of/base.c: In function 'of_populate_phandle_cache':
> drivers/of/base.c:182:7: warning: 'shadow' is used uninitialized in this function [-Wuninitialized]
>
> Here we create a merge fix-up that basically aligns the impacted code to
> match what is currently found in the 4.19-rt (as of v4.19.15-rt12).
>
> Reported-by: Yue Tao <Yue.Tao at windriver.com>
> Signed-off-by: Paul Gortmaker <paul.gortmaker at windriver.com>
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 904c7686f9d7..4a33ef482bcc 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -106,31 +106,34 @@ static u32 phandle_cache_mask;
> /*
> * Caller must hold devtree_lock.
> */
> -static void __of_free_phandle_cache(void)
> +static struct device_node** __of_free_phandle_cache(void)
> {
> u32 cache_entries = phandle_cache_mask + 1;
> u32 k;
> + struct device_node **shadow;
>
> if (!phandle_cache)
> - return;
> + return NULL;
>
> for (k = 0; k < cache_entries; k++)
> of_node_put(phandle_cache[k]);
>
> shadow = phandle_cache;
> phandle_cache = NULL;
> + return shadow;
> }
>
> int of_free_phandle_cache(void)
> {
> unsigned long flags;
> + struct device_node **shadow;
>
> raw_spin_lock_irqsave(&devtree_lock, flags);
>
> - __of_free_phandle_cache();
> + shadow = __of_free_phandle_cache();
>
> raw_spin_unlock_irqrestore(&devtree_lock, flags);
> -
> + kfree(shadow);
> return 0;
> }
> #if !defined(CONFIG_MODULES)
> @@ -169,27 +172,24 @@ void of_populate_phandle_cache(void)
>
> raw_spin_lock_irqsave(&devtree_lock, flags);
>
> - __of_free_phandle_cache();
> + shadow = __of_free_phandle_cache();
>
> for_each_of_allnodes(np)
> if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
> phandles++;
>
> - raw_spin_unlock_irqrestore(&devtree_lock, flags);
> - kfree(shadow);
> -
> if (!phandles)
> - return;
> + goto out;
> + raw_spin_unlock_irqrestore(&devtree_lock, flags);
>
> cache_entries = roundup_pow_of_two(phandles);
> phandle_cache_mask = cache_entries - 1;
>
> - shadow = kcalloc(cache_entries, sizeof(*phandle_cache), GFP_KERNEL);
> -
> - if (!shadow)
> - return;
> + phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
> + GFP_ATOMIC);
> raw_spin_lock_irqsave(&devtree_lock, flags);
> - phandle_cache = shadow;
> + if (!phandle_cache)
> + goto out;
>
> for_each_of_allnodes(np)
> if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) {
> @@ -197,7 +197,9 @@ void of_populate_phandle_cache(void)
> phandle_cache[np->phandle & phandle_cache_mask] = np;
> }
>
> +out:
> raw_spin_unlock_irqrestore(&devtree_lock, flags);
> + kfree(shadow);
> }
>
> void __init of_core_init(void)
> --
> 2.7.4
>
--
- Thou shalt not follow the NULL pointer, for chaos and madness await
thee at its end
- "Use the force Harry" - Gandalf, Star Trek II
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