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From: tndave <tushar.n.dave@oracle.com>
To: netdev@vger.kernel.org, "Kirsher,
	Jeffrey T" <jeffrey.t.kirsher@intel.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
	"Nelson, Shannon" <shannon.nelson@intel.com>,
	"Wyborny, Carolyn" <carolyn.wyborny@intel.com>,
	"Skidmore, Donald C" <donald.c.skidmore@intel.com>,
	"Allan, Bruce W" <bruce.w.allan@intel.com>,
	"Ronciak, John" <john.ronciak@intel.com>,
	mitch.a.williams@intel.com, intel-wired-lan@lists.osuosl.org
Cc: tushar.n.dave@oracle.com
Subject: i40e: Kernel unaligned access due to 'struct i40e_dma_mem' being 'packed'
Date: Wed, 27 Jan 2016 17:50:14 -0800	[thread overview]
Message-ID: <56A973D6.4060202@oracle.com> (raw)

Hi,

i40e driver has 'struct i40e_dma_mem' defined with 'packed' directive
causing kernel unaligned errors on sparc (when 40e_allocate_dma_mem_d()
is being called)

log_unaligned: 1031 callbacks suppressed
Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0
Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0
Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0
Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0

This can be fixed with get_unaligned/put_unaligned(). However I don't
see 'struct i40e_dma_mem' is being directly shoved into NIC hardware.
But instead fields of the struct are being read and used for hardware
(e.g. dma_addr_t pa). For the test, I remove __packed, and i40e driver
and HW works fine. (of course kernel unaligned errors are gone too).
My question is, does 'struct i40e_dma_mem' required to be __packed?

Thanks.

-Tushar

             reply	other threads:[~2016-01-28  1:50 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-28  1:50 tndave [this message]
2016-01-28  6:56 ` i40e: Kernel unaligned access due to 'struct i40e_dma_mem' being 'packed' David Miller
2016-01-29 22:47   ` tndave
2016-02-14  0:22     ` tndave

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