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    SubjectRe: [PATCH v5 02/18] ACPI / table: Add new function to get table entries
    On 2014/11/24 22:51, Rafael J. Wysocki wrote:
    > On Monday, November 24, 2014 07:03:54 PM Hanjun Guo wrote:
    >> On 2014-11-24 9:27, Rafael J. Wysocki wrote:
    >>> On Friday, October 17, 2014 09:36:58 PM Hanjun Guo wrote:
    >>>> From: Ashwin Chaugule <ashwin.chaugule@linaro.org>
    >>>>
    >>>> 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 <grant.likely@linaro.org>
    >>>> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
    >>>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
    >>>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
    >>>> ---
    >>>> 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.

    >>>
    >>>> 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:

    - 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);

    >>> 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?

    Thanks
    Hanjun



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