Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1589728

Re: [PATCH RESEND] drm/via: use get_user_pages_unlocked()

From Al Viro <viro@ZenIV.linux.org.uk>
Newsgroups linux.kernel
Subject Re: [PATCH RESEND] drm/via: use get_user_pages_unlocked()
Date 2017-02-28 20:40 +0100
Message-ID <tfVMS-oA-31@gated-at.bofh.it> (permalink)
References <tfBO9-3yE-25@gated-at.bofh.it> <tfLXc-2mX-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Tue, Feb 28, 2017 at 10:01:10AM +0100, Daniel Vetter wrote:

> > +	ret = get_user_pages_unlocked((unsigned long)xfer->mem_addr,
> > +			vsg->num_pages, vsg->pages,
> > +			(vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0);

Umm...  Why not
	ret = get_user_pages_fast((unsigned long)xfer->mem_addr,
			vsg->num_pages,
			vsg->direction == DMA_FROM_DEVICE,
			vsg->pages);

IOW, do you really need a warranty that ->mmap_sem will be grabbed and
released?

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH RESEND] drm/via: use get_user_pages_unlocked() Lorenzo Stoakes <lstoakes@gmail.com> - 2017-02-27 23:20 +0100
  Re: [PATCH RESEND] drm/via: use get_user_pages_unlocked() Daniel Vetter <daniel@ffwll.ch> - 2017-02-28 10:10 +0100
    Re: [PATCH RESEND] drm/via: use get_user_pages_unlocked() Al Viro <viro@ZenIV.linux.org.uk> - 2017-02-28 20:40 +0100
      Re: [PATCH RESEND] drm/via: use get_user_pages_unlocked() Lorenzo Stoakes <lstoakes@gmail.com> - 2017-02-28 21:40 +0100
        Re: [PATCH RESEND] drm/via: use get_user_pages_unlocked() Daniel Vetter <daniel@ffwll.ch> - 2017-03-01 09:50 +0100

csiph-web