On Tuesday, November 25, 2014 11:38:05 AM Hanjun Guo wrote:

On 2014/11/24 22:51, Rafael J. Wysocki wrote:

quoted

On Monday, November 24, 2014 07:03:54 PM Hanjun Guo wrote:

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On 2014-11-24 9:27, Rafael J. Wysocki wrote:

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On Friday, October 17, 2014 09:36:58 PM Hanjun Guo wrote:

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From: Ashwin Chaugule <redacted>

The acpi_table_parse() function has a callback that
passes a pointer to a table_header. Add a new function
which takes this pointer and parses its entries. This
eliminates the need to re-traverse all the tables for
each call. e.g. as in acpi_table_parse_madt() which is
normally called after acpi_table_parse().

Acked-by: Grant Likely <redacted>
Signed-off-by: Ashwin Chaugule <redacted>
Signed-off-by: Tomasz Nowicki <redacted>
Signed-off-by: Hanjun Guo <redacted>
---
 drivers/acpi/tables.c |   67 ++++++++++++++++++++++++++++++++++---------------
 include/linux/acpi.h  |    4 +++
 2 files changed, 51 insertions(+), 20 deletions(-)

diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 6d5a6cd..21ae521 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c

@@ -192,17 +192,14 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
 
 
 int __init
-acpi_table_parse_entries(char *id,
-			     unsigned long table_size,
-			     int entry_id,
-			     acpi_tbl_entry_handler handler,
-			     unsigned int max_entries)
+acpi_parse_entries(unsigned long table_size,
+		acpi_tbl_entry_handler handler,
+		struct acpi_table_header *table_header,
+		int entry_id, unsigned int max_entries)
 {
-	struct acpi_table_header *table_header = NULL;
 	struct acpi_subtable_header *entry;
-	unsigned int count = 0;
+	int count = 0;
 	unsigned long table_end;
-	acpi_size tbl_size;
 
 	if (acpi_disabled)
 		return -ENODEV;

@@ -210,13 +207,11 @@ acpi_table_parse_entries(char *id,
 	if (!handler)
 		return -EINVAL;
 
-	if (strncmp(id, ACPI_SIG_MADT, 4) == 0)
-		acpi_get_table_with_size(id, acpi_apic_instance, &table_header, &tbl_size);
-	else
-		acpi_get_table_with_size(id, 0, &table_header, &tbl_size);
+	if (!table_size)
+		return -EINVAL;
 
 	if (!table_header) {
-		pr_warn("%4.4s not present\n", id);
+		pr_warn("Table header not present\n");

The message doesn't make sense any more if the table signature is not printed.

For this message, since no table id is passed, and this message is printed in
acpi_table_parse_entries() before this function is called, I think we can check
the table_header before call this function and remove the printed message here.

table_header needs to be checked against NULL in the caller and the message
printed from there to my eyes.

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 		return -ENODEV;
 	}
 

@@ -232,30 +227,62 @@ acpi_table_parse_entries(char *id,
 		if (entry->type == entry_id
 		    && (!max_entries || count++ < max_entries))
 			if (handler(entry, table_end))
-				goto err;
+				return -EINVAL;
 
 		/*
 		 * If entry->length is 0, break from this loop to avoid
 		 * infinite loop.
 		 */
 		if (entry->length == 0) {
-			pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, entry_id);
-			goto err;
+			pr_err("[0x%02x] Invalid zero length\n", entry_id);

For this one, since the table_header is valid now, we can keep it with:

Fine by me.

- pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, entry_id);
+ pr_err("[%4.4s:0x%02x] Invalid zero length\n", table_header->signature, entry_id);

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Same here.

How about remove the message and return directly?

We could do that, but for what reason?  Is the message not useful?

I agree with you, the message is useful I think, how about the comments above?

Please see above.

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.