Messages in this thread Patch in this message | | | Date | Mon, 24 Nov 2014 09:34:24 +0100 | From | Tomasz Nowicki <> | Subject | Re: [PATCH v5 03/18] ACPI / table: Count matched and successfully parsed entries without specifying max entries |
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On 24.11.2014 02:45, Rafael J. Wysocki wrote: > On Friday, October 17, 2014 09:36:59 PM Hanjun Guo wrote: >> From: Tomasz Nowicki <tomasz.nowicki@linaro.org> >> >> It is very useful to traverse all available table entries without max >> number of expected entries type. Current acpi_parse_entries() >> implementation gives that feature but it does not count those entries, >> it returns 0 instead, so fix it to count matched and successfully >> entries and return it. > > Hmm. I guess that the goal is for count to only be incremented when the > condition is satisfied entirely, while without the patch it may be incremented > even if that isn't the case.
That would be our goal if patch would look like: - && (!max_entries || count++ < max_entries)) + && (!max_entries && count++ < max_entries)) { but then we can not walk through all available entries (with max_entries==0)
> > I'm not sure how that is related to the above paragraph, however. >
Previous changelog is not clear, let me rewrite it:
acpi_parse_entries() allows to traverse all available table entries (aka subtables) by passing max_entries parameter equal to 0. But for that use case acpi_parse_entries() does not inform caller how many entries were matched and for how many entries handler was run against. That patch is going to fix it.
Regards, Tomasz
>> NOTE: This change has no impact to x86 and ia64 archs since existing code >> checks for error occurrence only (acpi_parse_entries(...,0) < 0). >> >> Acked-by: Grant Likely <grant.likely@linaro.org> >> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org> >> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org> >> --- >> drivers/acpi/tables.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c >> index 21ae521..b18e45e 100644 >> --- a/drivers/acpi/tables.c >> +++ b/drivers/acpi/tables.c >> @@ -225,10 +225,13 @@ acpi_parse_entries(unsigned long table_size, >> while (((unsigned long)entry) + sizeof(struct acpi_subtable_header) < >> table_end) { >> if (entry->type == entry_id >> - && (!max_entries || count++ < max_entries)) >> + && (!max_entries || count < max_entries)) { >> if (handler(entry, table_end)) >> return -EINVAL; >> >> + count++; >> + } >> + >> /* >> * If entry->length is 0, break from this loop to avoid >> * infinite loop. >> >
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