* [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC
@ 2022-07-04 14:01 Fabio M. De Francesco
2022-07-05 18:21 ` Ira Weiny
2022-08-04 13:53 ` [Intel-wired-lan] " G, GurucharanX
0 siblings, 2 replies; 4+ messages in thread
From: Fabio M. De Francesco @ 2022-07-04 14:01 UTC (permalink / raw)
To: Jesse Brandeburg, Tony Nguyen, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Alexei Starovoitov, Daniel Borkmann,
Jesper Dangaard Brouer, John Fastabend, intel-wired-lan, netdev,
linux-kernel, bpf
Cc: Fabio M. De Francesco, Ira Weiny, Alexander Duyck
Pages allocated with GFP_ATOMIC cannot come from Highmem. This is why
there is no need to call kmap() on them.
Therefore, don't call kmap() on rx_buffer->page() and instead use a
plain page_address() to get the kernel address.
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Suggested-by: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
index 628d0eb0599f..71196fd92f81 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
@@ -1966,15 +1966,13 @@ static bool ixgbe_check_lbtest_frame(struct ixgbe_rx_buffer *rx_buffer,
frame_size >>= 1;
- data = kmap(rx_buffer->page) + rx_buffer->page_offset;
+ data = page_address(rx_buffer->page) + rx_buffer->page_offset;
if (data[3] != 0xFF ||
data[frame_size + 10] != 0xBE ||
data[frame_size + 12] != 0xAF)
match = false;
- kunmap(rx_buffer->page);
-
return match;
}
--
2.36.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC
2022-07-04 14:01 [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC Fabio M. De Francesco
@ 2022-07-05 18:21 ` Ira Weiny
2022-07-05 19:52 ` Alexander Duyck
2022-08-04 13:53 ` [Intel-wired-lan] " G, GurucharanX
1 sibling, 1 reply; 4+ messages in thread
From: Ira Weiny @ 2022-07-05 18:21 UTC (permalink / raw)
To: Fabio M. De Francesco
Cc: Jesse Brandeburg, Tony Nguyen, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Alexei Starovoitov, Daniel Borkmann,
Jesper Dangaard Brouer, John Fastabend, intel-wired-lan, netdev,
linux-kernel, bpf, Alexander Duyck
On Mon, Jul 04, 2022 at 04:01:29PM +0200, Fabio M. De Francesco wrote:
> Pages allocated with GFP_ATOMIC cannot come from Highmem. This is why
> there is no need to call kmap() on them.
I'm still not 100% sure where this page gets allocated but AFAICT it is
allocated in ixgbe_alloc_mapped_page() which calls dev_alloc_pages() for the
allocation which is where the GFP_ATOMIC is specified.
I think I would add this detail here.
That said, and assuming my analysis is correct, the code looks fine so:
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
>
> Therefore, don't call kmap() on rx_buffer->page() and instead use a
> plain page_address() to get the kernel address.
>
> Suggested-by: Ira Weiny <ira.weiny@intel.com>
> Suggested-by: Alexander Duyck <alexander.duyck@gmail.com>
> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> ---
> drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
> index 628d0eb0599f..71196fd92f81 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c
> @@ -1966,15 +1966,13 @@ static bool ixgbe_check_lbtest_frame(struct ixgbe_rx_buffer *rx_buffer,
>
> frame_size >>= 1;
>
> - data = kmap(rx_buffer->page) + rx_buffer->page_offset;
> + data = page_address(rx_buffer->page) + rx_buffer->page_offset;
>
> if (data[3] != 0xFF ||
> data[frame_size + 10] != 0xBE ||
> data[frame_size + 12] != 0xAF)
> match = false;
>
> - kunmap(rx_buffer->page);
> -
> return match;
> }
>
> --
> 2.36.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC
2022-07-05 18:21 ` Ira Weiny
@ 2022-07-05 19:52 ` Alexander Duyck
0 siblings, 0 replies; 4+ messages in thread
From: Alexander Duyck @ 2022-07-05 19:52 UTC (permalink / raw)
To: Ira Weiny
Cc: Fabio M. De Francesco, Jesse Brandeburg, Tony Nguyen,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Alexei Starovoitov, Daniel Borkmann, Jesper Dangaard Brouer,
John Fastabend, intel-wired-lan, Netdev, LKML, bpf
On Tue, Jul 5, 2022 at 11:22 AM Ira Weiny <ira.weiny@intel.com> wrote:
>
> On Mon, Jul 04, 2022 at 04:01:29PM +0200, Fabio M. De Francesco wrote:
> > Pages allocated with GFP_ATOMIC cannot come from Highmem. This is why
> > there is no need to call kmap() on them.
>
> I'm still not 100% sure where this page gets allocated but AFAICT it is
> allocated in ixgbe_alloc_mapped_page() which calls dev_alloc_pages() for the
> allocation which is where the GFP_ATOMIC is specified.
>
> I think I would add this detail here.
>
> That said, and assuming my analysis is correct, the code looks fine so:
Yeah, this is actually called out in other spots in the buffer
cleaning path. This is just something I had overlooked and left in
place back a few refactors ago.. :-)
https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c#L1795
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: [Intel-wired-lan] [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC
2022-07-04 14:01 [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC Fabio M. De Francesco
2022-07-05 18:21 ` Ira Weiny
@ 2022-08-04 13:53 ` G, GurucharanX
1 sibling, 0 replies; 4+ messages in thread
From: G, GurucharanX @ 2022-08-04 13:53 UTC (permalink / raw)
To: Fabio M. De Francesco, Brandeburg, Jesse, Nguyen, Anthony L,
David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Alexei Starovoitov, Daniel Borkmann, Jesper Dangaard Brouer,
John Fastabend, intel-wired-lan, netdev, linux-kernel, bpf
Cc: Weiny, Ira
> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Fabio M. De Francesco
> Sent: Monday, July 4, 2022 7:31 PM
> To: Brandeburg, Jesse <jesse.brandeburg@intel.com>; Nguyen, Anthony L
> <anthony.l.nguyen@intel.com>; David S. Miller <davem@davemloft.net>;
> Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>;
> Paolo Abeni <pabeni@redhat.com>; Alexei Starovoitov <ast@kernel.org>;
> Daniel Borkmann <daniel@iogearbox.net>; Jesper Dangaard Brouer
> <hawk@kernel.org>; John Fastabend <john.fastabend@gmail.com>; intel-
> wired-lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; bpf@vger.kernel.org
> Cc: Weiny, Ira <ira.weiny@intel.com>; Fabio M. De Francesco
> <fmdefrancesco@gmail.com>
> Subject: [Intel-wired-lan] [PATCH] ixgbe: Don't call kmap() on page allocated
> with GFP_ATOMIC
>
> Pages allocated with GFP_ATOMIC cannot come from Highmem. This is why
> there is no need to call kmap() on them.
>
> Therefore, don't call kmap() on rx_buffer->page() and instead use a plain
> page_address() to get the kernel address.
>
> Suggested-by: Ira Weiny <ira.weiny@intel.com>
> Suggested-by: Alexander Duyck <alexander.duyck@gmail.com>
> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
> ---
> drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-08-04 13:53 UTC | newest]
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2022-07-04 14:01 [PATCH] ixgbe: Don't call kmap() on page allocated with GFP_ATOMIC Fabio M. De Francesco
2022-07-05 18:21 ` Ira Weiny
2022-07-05 19:52 ` Alexander Duyck
2022-08-04 13:53 ` [Intel-wired-lan] " G, GurucharanX
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