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Message-Id: <3rbRd54y9Vz9t0p@ozlabs.org>
Date: Fri, 24 Jun 2016 15:26:01 +1000 (AEST)
From: Michael Ellerman <mpe@...erman.id.au>
To: Hari Bathini <hbathini@...ux.vnet.ibm.com>,
lkml <linux-kernel@...r.kernel.org>,
linuxppc-dev <linuxppc-dev@...abs.org>
Cc: Rusty Russell <rusty@...tcorp.com.au>, kexec@...ts.infradead.org,
Eric Biederman <ebiederm@...ssion.com>,
Vivek Goyal <vgoyal@...hat.com>
Subject: Re: [v2,1/2] refactor code parsing size based on memory range
On Wed, 2016-22-06 at 19:25:26 UTC, Hari Bathini wrote:
> Currently, crashkernel parameter supports the below syntax to parse size
> based on memory range:
>
> crashkernel=<range1>:<size1>[,<range2>:<size2>,...]
>
> While such parsing is implemented for crashkernel parameter, it applies to
> other parameters with similar syntax. So, move this code to a more generic
> place for code reuse.
>
> Cc: Eric Biederman <ebiederm@...ssion.com>
> Cc: Vivek Goyal <vgoyal@...hat.com>
> Cc: Rusty Russell <rusty@...tcorp.com.au>
> Cc: kexec@...ts.infradead.org
> Signed-off-by: Hari Bathini <hbathini@...ux.vnet.ibm.com>
Hari, it's not immediately clear that this makes no change to the logic in the
kexec code. Can you reply with a longer change log explaining why the old & new
logic is the same for kexec.
cheers
> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
> index 94aa10f..72f55e5 100644
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -436,6 +436,11 @@ extern char *get_options(const char *str, int nints, int *ints);
> extern unsigned long long memparse(const char *ptr, char **retptr);
> extern bool parse_option_str(const char *str, const char *option);
>
> +extern bool __init is_param_range_based(const char *cmdline);
> +extern unsigned long long __init parse_mem_range_size(const char *param,
> + char **str,
> + unsigned long long system_ram);
> +
> extern int core_kernel_text(unsigned long addr);
> extern int core_kernel_data(unsigned long addr);
> extern int __kernel_text_address(unsigned long addr);
> diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
> index 56b3ed0..d43f5cc 100644
> --- a/kernel/kexec_core.c
> +++ b/kernel/kexec_core.c
> @@ -1083,59 +1083,9 @@ static int __init parse_crashkernel_mem(char *cmdline,
> char *cur = cmdline, *tmp;
>
> /* for each entry of the comma-separated list */
> - do {
> - unsigned long long start, end = ULLONG_MAX, size;
> -
> - /* get the start of the range */
> - start = memparse(cur, &tmp);
> - if (cur == tmp) {
> - pr_warn("crashkernel: Memory value expected\n");
> - return -EINVAL;
> - }
> - cur = tmp;
> - if (*cur != '-') {
> - pr_warn("crashkernel: '-' expected\n");
> - return -EINVAL;
> - }
> - cur++;
> -
> - /* if no ':' is here, than we read the end */
> - if (*cur != ':') {
> - end = memparse(cur, &tmp);
> - if (cur == tmp) {
> - pr_warn("crashkernel: Memory value expected\n");
> - return -EINVAL;
> - }
> - cur = tmp;
> - if (end <= start) {
> - pr_warn("crashkernel: end <= start\n");
> - return -EINVAL;
> - }
> - }
> -
> - if (*cur != ':') {
> - pr_warn("crashkernel: ':' expected\n");
> - return -EINVAL;
> - }
> - cur++;
> -
> - size = memparse(cur, &tmp);
> - if (cur == tmp) {
> - pr_warn("Memory value expected\n");
> - return -EINVAL;
> - }
> - cur = tmp;
> - if (size >= system_ram) {
> - pr_warn("crashkernel: invalid size\n");
> - return -EINVAL;
> - }
> -
> - /* match ? */
> - if (system_ram >= start && system_ram < end) {
> - *crash_size = size;
> - break;
> - }
> - } while (*cur++ == ',');
> + *crash_size = parse_mem_range_size("crashkernel", &cur, system_ram);
> + if (cur == cmdline)
> + return -EINVAL;
>
> if (*crash_size > 0) {
> while (*cur && *cur != ' ' && *cur != '@')
> @@ -1272,7 +1222,6 @@ static int __init __parse_crashkernel(char *cmdline,
> const char *name,
> const char *suffix)
> {
> - char *first_colon, *first_space;
> char *ck_cmdline;
>
> BUG_ON(!crash_size || !crash_base);
> @@ -1290,12 +1239,10 @@ static int __init __parse_crashkernel(char *cmdline,
> return parse_crashkernel_suffix(ck_cmdline, crash_size,
> suffix);
> /*
> - * if the commandline contains a ':', then that's the extended
> + * if the parameter is range based, then that's the extended
> * syntax -- if not, it must be the classic syntax
> */
> - first_colon = strchr(ck_cmdline, ':');
> - first_space = strchr(ck_cmdline, ' ');
> - if (first_colon && (!first_space || first_colon < first_space))
> + if (is_param_range_based(ck_cmdline))
> return parse_crashkernel_mem(ck_cmdline, system_ram,
> crash_size, crash_base);
>
> diff --git a/kernel/params.c b/kernel/params.c
> index a6d6149..84e40ae 100644
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -268,6 +268,102 @@ char *parse_args(const char *doing,
> return err;
> }
>
> +/*
> + * is_param_range_based - check if current parameter is range based
> + * @cmdline: points to the parameter to check
> + *
> + * Returns true when the current paramer is range based, false otherwise
> + */
> +bool __init is_param_range_based(const char *cmdline)
> +{
> + char *first_colon, *first_space;
> +
> + first_colon = strchr(cmdline, ':');
> + first_space = strchr(cmdline, ' ');
> + if (first_colon && (!first_space || first_colon < first_space))
> + return true;
> +
> + return false;
> +}
> +
> +/*
> + * parse_mem_range_size - parse size based on memory range
> + * @param: the thing being parsed
> + * @str: (input) where parse begins
> + * expected format - <range1>:<size1>[,<range2>:<size2>,...]
> + * (output) On success - next char after parse completes
> + * On failure - unchanged
> + * @system_ram: system ram size to check memory range against
> + *
> + * Returns the memory size on success and 0 on failure
> + */
> +unsigned long long __init parse_mem_range_size(const char *param,
> + char **str,
> + unsigned long long system_ram)
> +{
> + char *cur = *str, *tmp;
> + unsigned long long mem_size = 0;
> +
> + /* for each entry of the comma-separated list */
> + do {
> + unsigned long long start, end = ULLONG_MAX, size;
> +
> + /* get the start of the range */
> + start = memparse(cur, &tmp);
> + if (cur == tmp) {
> + printk(KERN_INFO "%s: Memory value expected\n", param);
> + return mem_size;
> + }
> + cur = tmp;
> + if (*cur != '-') {
> + printk(KERN_INFO "%s: '-' expected\n", param);
> + return mem_size;
> + }
> + cur++;
> +
> + /* if no ':' is here, than we read the end */
> + if (*cur != ':') {
> + end = memparse(cur, &tmp);
> + if (cur == tmp) {
> + printk(KERN_INFO "%s: Memory value expected\n",
> + param);
> + return mem_size;
> + }
> + cur = tmp;
> + if (end <= start) {
> + printk(KERN_INFO "%s: end <= start\n", param);
> + return mem_size;
> + }
> + }
> +
> + if (*cur != ':') {
> + printk(KERN_INFO "%s: ':' expected\n", param);
> + return mem_size;
> + }
> + cur++;
> +
> + size = memparse(cur, &tmp);
> + if (cur == tmp) {
> + printk(KERN_INFO "%s: Memory value expected\n", param);
> + return mem_size;
> + }
> + cur = tmp;
> + if (size >= system_ram) {
> + printk(KERN_INFO "%s: invalid size\n", param);
> + return mem_size;
> + }
> +
> + /* match ? */
> + if (system_ram >= start && system_ram < end) {
> + mem_size = size;
> + *str = cur;
> + break;
> + }
> + } while (*cur++ == ',');
> +
> + return mem_size;
> +}
> +
> /* Lazy bastard, eh? */
> #define STANDARD_PARAM_DEF(name, type, format, strtolfn) \
> int param_set_##name(const char *val, const struct kernel_param *kp) \
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