[RESEND][PATCH v2 1/2] kexec: refactor code parsing size based on memory range
Hari Bathini
hbathini at linux.vnet.ibm.com
Fri Aug 5 05:04:48 AEST 2016
Hi Dave
Thanks for the review..
On Thursday 04 August 2016 02:56 PM, Dave Young wrote:
> Hi Hari,
>
> On 08/04/16 at 01:03am, Hari Bathini wrote:
>> crashkernel parameter supports different syntaxes to specify the amount
>> of memory to be reserved for kdump kernel. Below is one of the supported
>> syntaxes that needs parsing to find the memory size to reserve, based on
>> memory range:
>>
>> crashkernel=<range1>:<size1>[,<range2>:<size2>,...]
>>
>> While such parsing is implemented for crashkernel parameter, it applies
>> to other parameters, like fadump_reserve_mem=, which could use similar
>> syntax. This patch moves crashkernel's parsing code for above syntax to
>> to kernel/params.c file for reuse. Two functions is_param_range_based()
>> and parse_mem_range_size() are added to kernel/params.c file for this
>> purpose.
>>
>> Any parameter that uses the above syntax can use is_param_range_based()
>> function to validate the syntax and parse_mem_range_size() function to
>> get the parsed memory size. While some code is moved to kernel/params.c
>> file, there is no change functionality wise in parsing the crashkernel
>> parameter.
>>
>> Signed-off-by: Hari Bathini <hbathini at linux.vnet.ibm.com>
>> ---
>>
>> Changes from v1:
>> 1. Updated changelog
>>
>> include/linux/kernel.h | 5 +++
>> kernel/kexec_core.c | 63 +++-----------------------------
>> kernel/params.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 106 insertions(+), 58 deletions(-)
>>
>> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
>> index d96a611..2df7ba2 100644
>> --- a/include/linux/kernel.h
>> +++ b/include/linux/kernel.h
>> @@ -435,6 +435,11 @@ 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 5616755..3a74024 100644
>> --- a/kernel/kexec_core.c
>> +++ b/kernel/kexec_core.c
>> @@ -1104,59 +1104,9 @@ 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 != '@')
>> @@ -1293,7 +1243,6 @@ 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);
>> @@ -1311,12 +1260,10 @@ 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
> /lib/cmdline.c is a better place for this?
True. Will change accordingly..
>> @@ -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
>> + */
> It is not necessary to be range specific? Maybe is_colon_in_param or
> something else. If it is range based we need know what is the range
> like.
Hmmm.. I prefer to rename it to is_colon_in_param() and avoid
adding anymore checks here..
>> +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>,...]
> There should be detail example about the range format, especially about
> the "-" separator.
>
Sure..
>> + * (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",
> s/Memory/memory?
I haven't changed the content of print messages while moving them around.
Probably I should..
- Hari
>> + 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);
> Ditto.
>
>> + 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) \
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
> Thanks
> Dave
>
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