[PATCH v9 0/7] Introduce sendpage_ok() to detect misused sendpage in network related drivers

[David Miller]

From: Coly Li <colyli at suse.de>
Date: Thu,  1 Oct 2020 15:54:01 +0800

> This series was original by a bug fix in nvme-over-tcp driver which only
> checked whether a page was allocated from slab allcoator, but forgot to
> check its page_count: The page handled by sendpage should be neither a
> Slab page nor 0 page_count page.
> 
> As Sagi Grimberg suggested, the original fix is refind to a more common
> inline routine:
>     static inline bool sendpage_ok(struct page *page)
>     {
>         return  (!PageSlab(page) && page_count(page) >= 1);
>     }
> If sendpage_ok() returns true, the checking page can be handled by the
> concrete zero-copy sendpage method in network layer.
> 
> The v9 series has 7 patches, no change from v8 series,
> - The 1st patch in this series introduces sendpage_ok() in header file
>   include/linux/net.h.
> - The 2nd patch adds WARN_ONCE() for improper zero-copy send in
>   kernel_sendpage().
> - The 3rd patch fixes the page checking issue in nvme-over-tcp driver.
> - The 4th patch adds page_count check by using sendpage_ok() in
>   do_tcp_sendpages() as Eric Dumazet suggested.
> - The 5th and 6th patches just replace existing open coded checks with
 ...

Series applied and queued up for -stable, thank you.