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RE: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets

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> From: David Miller [mailto:davem@davemloft.net]
> Sent: Tuesday, June 28, 2016 17:34
> To: Dexuan Cui <decui@microsoft.com>
> Cc: gregkh@linuxfoundation.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de;
> apw@canonical.com; jasowang@redhat.com; vkuznets@redhat.com;
> cavery@redhat.com; KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; joe@perches.com
> Subject: Re: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets
> 
> From: Dexuan Cui <decui@microsoft.com>
> Date: Fri, 24 Jun 2016 07:45:24 +0000
> 
> > +	while ((ret = vmalloc(size)) == NULL)
> > +		ssleep(1);
> 
> This is completely, and entirely, unacceptable.
> 
> If the allocation fails, you return an error and release
> your resources.
> 
> You don't just loop forever waiting for it to succeed.

Hi David,
I agree this is ugly...

The idea here is: IMO the syscalls sys_read()/write() shoudn't return
-ENOMEM, so I have to make sure the buffer allocation succeeds?

I tried to use kmalloc with __GFP_NOFAIL, but I hit a warning in 
in mm/page_alloc.c:
WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1));

What error code do you think I should return? 
EAGAIN, ERESTARTSYS, or something else?

May I have your suggestion? Thanks!

-- Dexuan

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Re: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets David Miller <davem@davemloft.net> - 2016-06-28 11:40 +0200
  RE: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets Dexuan Cui <decui@microsoft.com> - 2016-06-28 13:00 +0200
    Re: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets David Miller <davem@davemloft.net> - 2016-06-28 15:50 +0200
      RE: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets Dexuan Cui <decui@microsoft.com> - 2016-06-28 17:40 +0200
    Re: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets Rick Jones <rick.jones2@hpe.com> - 2016-06-28 17:50 +0200
      RE: [PATCH v12 net-next 1/1] hv_sock: introduce Hyper-V Sockets Dexuan Cui <decui@microsoft.com> - 2016-06-29 11:20 +0200

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