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From: Christoph Hellwig <[email protected]>
To: Yan Zhao <[email protected]>
Cc: Christoph Hellwig <[email protected]>,
	Linus Torvalds <[email protected]>,
	Andrew Morton <[email protected]>,
	Jens Axboe <[email protected]>, Felipe Balbi <[email protected]>,
	[email protected],
	"Michael S. Tsirkin" <[email protected]>,
	Felix Kuehling <[email protected]>,
	[email protected], [email protected],
	[email protected],
	Zhenyu Wang <[email protected]>,
	[email protected], [email protected],
	[email protected], Al Viro <[email protected]>,
	[email protected],
	Alex Deucher <[email protected]>,
	[email protected],
	Jason Wang <[email protected]>, Zhi Wang <[email protected]>
Subject: Re: [PATCH 2/6] i915/gvt/kvm: a NULL ->mm does not mean a thread is a kthread
Date: Mon, 13 Apr 2020 15:27:30 +0200	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <20200407030845.GA10586@joy-OptiPlex-7040>

On Mon, Apr 06, 2020 at 11:08:46PM -0400, Yan Zhao wrote:
> hi
> we were removing this code. see
> https://lore.kernel.org/kvm/[email protected]/

This didn't make 5.7-rc1.

> The implementation of vfio_dma_rw() has been in vfio next tree.
> https://github.com/awilliam/linux-vfio/commit/8d46c0cca5f4dc0538173d62cd36b1119b5105bc


This made 5.7-rc1, so I'll update the series to take it into account.

T
> in vfio_dma_rw(),  we still use
> bool kthread = current->mm == NULL.
> because if current->mm != NULL and current->flags & PF_KTHREAD, instead
> of calling use_mm(), we first check if (current->mm == mm) and allow copy_to_user() if it's true.
> 
> Do you think it's all right?

I can't think of another way for a kernel thread to have a mm indeed.

  reply	other threads:[~2020-04-13 13:27 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-04  9:40 improve use_mm / unuse_mm Christoph Hellwig
2020-04-04  9:40 ` [PATCH 1/6] amdgpu: a NULL ->mm does not mean a thread is a kthread Christoph Hellwig
2020-04-06 16:07   ` Felix Kuehling
2020-04-04  9:40 ` [PATCH 2/6] i915/gvt/kvm: " Christoph Hellwig
2020-04-04 10:05   ` Sergei Shtylyov
2020-04-07  3:08   ` Yan Zhao
2020-04-13 13:27     ` Christoph Hellwig [this message]
2020-04-14  0:04       ` Yan Zhao
2020-04-14  7:00         ` Christoph Hellwig
2020-04-14  7:03           ` Yan Zhao
2020-04-04  9:40 ` [PATCH 3/6] i915/gvt: remove unused xen bits Christoph Hellwig
2020-04-08  1:44   ` Zhenyu Wang
2020-04-13 13:08     ` Christoph Hellwig
2020-04-14  3:04       ` Zhenyu Wang
2020-04-04  9:40 ` [PATCH 4/6] kernel: move use_mm/unuse_mm to kthread.c Christoph Hellwig
2020-04-06 16:09   ` Felix Kuehling
2020-04-04  9:41 ` [PATCH 5/6] kernel: better document the use_mm/unuse_mm API contract Christoph Hellwig
2020-04-04 13:07   ` [Intel-gfx] " Pavel Begunkov
2020-04-06 16:10   ` Felix Kuehling
2020-04-04  9:41 ` [PATCH 6/6] kernel: set USER_DS in kthread_use_mm Christoph Hellwig
2020-04-06 21:49   ` Michael S. Tsirkin

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