83 lines
2.2 KiB
Diff
83 lines
2.2 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 31 Aug 2018 14:16:30 +0200
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Subject: [PATCH] of: allocate / free phandle cache outside of the devtree_lock
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.18/older/patches-4.18.7-rt5.tar.xz
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The phandle cache code allocates memory while holding devtree_lock which
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is a raw_spinlock_t. Memory allocation (and free()) is not possible on
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RT while a raw_spinlock_t is held.
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Invoke the kfree() and kcalloc() while the lock is dropped.
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Cc: Rob Herring <robh+dt@kernel.org>
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Cc: Frank Rowand <frowand.list@gmail.com>
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Cc: devicetree@vger.kernel.org
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/of/base.c | 22 ++++++++++++++--------
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1 file changed, 14 insertions(+), 8 deletions(-)
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--- a/drivers/of/base.c
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+++ b/drivers/of/base.c
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@@ -108,46 +108,52 @@ void of_populate_phandle_cache(void)
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u32 cache_entries;
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struct device_node *np;
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u32 phandles = 0;
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+ struct device_node **shadow;
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raw_spin_lock_irqsave(&devtree_lock, flags);
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-
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- kfree(phandle_cache);
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+ shadow = phandle_cache;
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phandle_cache = NULL;
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for_each_of_allnodes(np)
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if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
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phandles++;
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+ raw_spin_unlock_irqrestore(&devtree_lock, flags);
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+
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if (!phandles)
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- goto out;
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+ return;
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cache_entries = roundup_pow_of_two(phandles);
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phandle_cache_mask = cache_entries - 1;
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- phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
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- GFP_ATOMIC);
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- if (!phandle_cache)
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- goto out;
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+ kfree(shadow);
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+ shadow = kcalloc(cache_entries, sizeof(*phandle_cache), GFP_KERNEL);
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+
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+ if (!shadow)
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+ return;
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+ raw_spin_lock_irqsave(&devtree_lock, flags);
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+ phandle_cache = shadow;
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for_each_of_allnodes(np)
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if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
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phandle_cache[np->phandle & phandle_cache_mask] = np;
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-out:
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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}
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int of_free_phandle_cache(void)
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{
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unsigned long flags;
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+ struct device_node **shadow;
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raw_spin_lock_irqsave(&devtree_lock, flags);
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- kfree(phandle_cache);
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+ shadow = phandle_cache;
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phandle_cache = NULL;
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raw_spin_unlock_irqrestore(&devtree_lock, flags);
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+ kfree(shadow);
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return 0;
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}
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#if !defined(CONFIG_MODULES)
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