gpiolib: Fix locking on gpio debugfs files
The debugfs files really need to hold the gpiolib spinlock before accessing the list. Otherwise chip addition/removal will cause an oops. Cc: Alexandre Courbot <acourbot@nvidia.com> Cc: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
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@ -2053,29 +2053,35 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
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static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
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static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
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{
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{
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unsigned long flags;
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struct gpio_chip *chip = NULL;
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struct gpio_chip *chip = NULL;
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loff_t index = *pos;
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loff_t index = *pos;
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/* REVISIT this isn't locked against gpio_chip removal ... */
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s->private = "";
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s->private = "";
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spin_lock_irqsave(&gpio_lock, flags);
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list_for_each_entry(chip, &gpio_chips, list)
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list_for_each_entry(chip, &gpio_chips, list)
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if (index-- == 0)
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if (index-- == 0) {
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spin_unlock_irqrestore(&gpio_lock, flags);
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return chip;
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return chip;
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}
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spin_unlock_irqrestore(&gpio_lock, flags);
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return NULL;
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return NULL;
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}
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}
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static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
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static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
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{
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{
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unsigned long flags;
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struct gpio_chip *chip = v;
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struct gpio_chip *chip = v;
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void *ret = NULL;
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void *ret = NULL;
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spin_lock_irqsave(&gpio_lock, flags);
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if (list_is_last(&chip->list, &gpio_chips))
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if (list_is_last(&chip->list, &gpio_chips))
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ret = NULL;
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ret = NULL;
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else
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else
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ret = list_entry(chip->list.next, struct gpio_chip, list);
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ret = list_entry(chip->list.next, struct gpio_chip, list);
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spin_unlock_irqrestore(&gpio_lock, flags);
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s->private = "\n";
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s->private = "\n";
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++*pos;
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++*pos;
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