> -----Original Message-----
> From: linux-kernel-ow...@vger.kernel.org [mailto:linux-kernel-
> ow...@vger.kernel.org] On Behalf Of Pan Xinhui
> Sent: Thursday, July 23, 2015 4:54 AM
> To: linux-kernel@vger.kernel.org
> Subject: [PATCH] x86/mm/pat: Do a small optimization when dump PAT memtype
> list
...
> diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
> index 268b2c8..6302119 100644
> --- a/arch/x86/mm/pat.c
> +++ b/arch/x86/mm/pat.c
> @@ -1001,45 +1001,42 @@ EXPORT_SYMBOL_GPL(pgprot_writethrough);
>
> #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
>
> -static struct memtype *memtype_get_idx(loff_t pos)
> +static struct memtype *memtype_get_idx(struct memtype *entry, loff_t pos)
> {
> - struct memtype *print_entry;
> int ret;
>
> - print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL);
> - if (!print_entry)
> - return NULL;
> -
> spin_lock(&memtype_lock);
> - ret = rbt_memtype_copy_nth_element(print_entry, pos);
> + ret = rbt_memtype_copy_nth_element(entry, pos);
> spin_unlock(&memtype_lock);
>
> - if (!ret) {
> - return print_entry;
> - } else {
> - kfree(print_entry);
> - return NULL;
> - }
> + return ret ? NULL : entry;
> }
>
...
> static void memtype_seq_stop(struct seq_file *seq, void *v)
> {
> + kfree(seq->private);
> }
>
Consider adding
seq->private = NULL;
so the stale pointer isn't left around. There's probably not
much risk of accessing it, but NULL is safer in case it is.
---
Robert Elliott, HP Server Storage
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