On 10/06/2024 13:05, Sagi Grimberg wrote:
>
>
> On 06/06/2024 19:12, Ofir Gal wrote:
>> Network drivers are using sendpage_ok() to check the first page of an
>> iterator in order to disable MSG_SPLICE_PAGES. The iterator can
>> represent list of contiguous pages.
>>
>> When MSG_SPLICE_PAGES is enabled skb_splice_from_iter() is being used,
>> it requires all pages in the iterator to be sendable. Therefore it needs
>> to check that each page is sendable.
>>
>> The patch introduces a helper sendpages_ok(), it returns true if all the
>> contiguous pages are sendable.
>>
>> Drivers who want to send contiguous pages with MSG_SPLICE_PAGES may use
>> this helper to check whether the page list is OK. If the helper does not
>> return true, the driver should remove MSG_SPLICE_PAGES flag.
>>
>> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
>> Signed-off-by: Ofir Gal <ofir.gal@xxxxxxxxxxx>
>> ---
>> include/linux/net.h | 22 ++++++++++++++++++++++
>> 1 file changed, 22 insertions(+)
>>
>> diff --git a/include/linux/net.h b/include/linux/net.h
>> index 688320b79fcc..421a6b5b9ad1 100644
>> --- a/include/linux/net.h
>> +++ b/include/linux/net.h
>> @@ -322,6 +322,28 @@ static inline bool sendpage_ok(struct page *page)
>> return !PageSlab(page) && page_count(page) >= 1;
>> }
>> +/*
>> + * Check sendpage_ok on contiguous pages.
>> + */
>> +static inline bool sendpages_ok(struct page *page, size_t len, size_t offset)
>> +{
>> + struct page *p;
>> + size_t count;
>> +
>> + p = page + (offset >> PAGE_SHIFT);
>> +
>> + count = 0;
>
> Assignment can move to the declaration.
Applying to v4.
>
>
>> + while (count < len) {
>> + if (!sendpage_ok(p))
>> + return false;
>> +
>> + p++;
>> + count += PAGE_SIZE;
>> + }
>> +
>> + return true;
>> +}
>> +
>> int kernel_sendmsg(struct socket *sock, struct msghdr *msg, struct kvec *vec,
>> size_t num, size_t len);
>> int kernel_sendmsg_locked(struct sock *sk, struct msghdr *msg,
>
> Other than that,
>
> Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Thanks for the review.
