Messages in this thread |  | | Date | Wed, 6 Feb 2013 13:54:09 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 3/3] acpi, memory-hotplug: Support getting hotplug info from SRAT. |
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On Wed, 06 Feb 2013 10:20:57 +0800 Tang Chen <tangchen@cn.fujitsu.com> wrote:
> >> > >> + if (!strncmp(p, "acpi", max(4, strlen(p)))) > >> + movablemem_map.acpi = true; > > > > Generates a warning: > > > > mm/page_alloc.c: In function 'cmdline_parse_movablemem_map': > > mm/page_alloc.c:5312: warning: comparison of distinct pointer types lacks a cast > > > > due to max(int, size_t). > > > > This is easily fixed, but the code looks rather pointless. If the > > incoming string is supposed to be exactly "acpi" then use strcmp(). If > > the incoming string must start with "acpi" then use strncmp(p, "acpi", 4). > > > > IOW, the max is unneeded? > > Hi Andrew, > > I think I made another mistake here. I meant to use min(4, strlen(p)) in > case p is > something like 'aaa' whose length is less then 4. But I mistook it with > max(). > > But after I dig into strcmp() in the kernel, I think it is OK to use > strcmp(). > min() or max() is not needed.
OK, I did that.
But the code still looks a bit more complex than we need. Could we do
static int __init cmdline_parse_movablemem_map(char *p) { char *oldp; u64 start_at, mem_size;
if (!p) goto err;
/* * If user decide to use info from BIOS, all the other user specified * ranges will be ingored. */ if (!strcmp(p, "acpi")) { movablemem_map.acpi = true; if (movablemem_map.nr_map) { memset(movablemem_map.map, 0, sizeof(struct movablemem_entry) * movablemem_map.nr_map); movablemem_map.nr_map = 0; } return 0; }
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