From: Michal Hocko <mhocko@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-rdma@vger.kernel.org,
Jason Gunthorpe <jgg@mellanox.com>,
Bernard Metzler <bmt@zurich.ibm.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: add dummy can_do_mlock() helper
Date: Tue, 10 Sep 2019 09:10:30 +0200 [thread overview]
Message-ID: <20190910071030.GG2063@dhcp22.suse.cz> (raw)
In-Reply-To: <20190909204201.931830-1-arnd@arndb.de>
On Mon 09-09-19 22:41:40, Arnd Bergmann wrote:
> On kernels without CONFIG_MMU, we get a link error for the siw
> driver:
>
> drivers/infiniband/sw/siw/siw_mem.o: In function `siw_umem_get':
> siw_mem.c:(.text+0x4c8): undefined reference to `can_do_mlock'
>
> This is probably not the only driver that needs the function
> and could otherwise build correctly without CONFIG_MMU, so
> add a dummy variant that always returns false.
>
> Fixes: 2251334dcac9 ("rdma/siw: application buffer management")
> Suggested-by: Jason Gunthorpe <jgg@mellanox.com>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Makes sense
Acked-by: Michal Hocko <mhocko@suse.com>
but IB on nonMMU? Whut? Is there any HW that actually supports this?
Just wondering...
> ---
> include/linux/mm.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 66f296181bcc..cc292273e6ba 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1424,7 +1424,11 @@ extern void pagefault_out_of_memory(void);
>
> extern void show_free_areas(unsigned int flags, nodemask_t *nodemask);
>
> +#ifdef CONFIG_MMU
> extern bool can_do_mlock(void);
> +#else
> +static inline bool can_do_mlock(void) { return false; }
> +#endif
> extern int user_shm_lock(size_t, struct user_struct *);
> extern void user_shm_unlock(size_t, struct user_struct *);
>
> --
> 2.20.0
>
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-09-10 7:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-09 20:41 [PATCH] mm: add dummy can_do_mlock() helper Arnd Bergmann
2019-09-10 7:10 ` Michal Hocko [this message]
2019-09-10 7:31 ` Arnd Bergmann
2019-09-10 8:40 ` Jason Gunthorpe
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