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@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
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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