From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vipul Pandya Subject: Re: [PATCH net-next 05/22] cxgb4: Add T5 write combining support Date: Wed, 13 Mar 2013 20:06:04 +0530 Message-ID: <51408ED4.40400@chelsio.com> References: <1363088794-31453-1-git-send-email-vipul@chelsio.com> <1363088794-31453-6-git-send-email-vipul@chelsio.com> <20130312.081927.1036246728528667686.davem@davemloft.net> <513F3EBD.5020504@opengridcomputing.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: David Miller , "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org" , "JBottomley-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org" , Dimitrios Michailidis , Casey Leedom , Naresh Kumar Inna , Divy Le Ray , Santosh Rastapur , Arvind Bhushan , Abhishek Agrawal To: Steve Wise Return-path: In-Reply-To: <513F3EBD.5020504-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On 12-03-2013 20:12, Steve Wise wrote: > On 3/12/2013 7:19 AM, David Miller wrote: >> From: Vipul Pandya >> Date: Tue, 12 Mar 2013 17:16:17 +0530 >> >>> + writel(n, adap->bar2 + q->udb + 8); >>> +#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64) >>> + asm volatile("sfence" : : : "memory"); >>> +#endif >> There is absolutely no way I'm letting anyone put crap like this >> into a driver. >> >> Use a portable inteface, and if one does not exist create one. > > I guess you'll have to add a wc_wmb() function for all the hw platforms > supported by the kernel. I see libibverbs defines this for the user > side in include/infiniband/arch.h, and that could be used as the meat of > the hw platform-specific implementations. > I see that normal wmb() code for x86_64 architecture is same as what above #ifdef condition is doing. To be more clear I looked at the assembly code for wmb and find that it is converted into 'sfence' instruction. So, I think above code should be replaced with wmb call which will also take care of portability on different architecture. I will submit the series again soon. I would like to request RDMA/cxgb4 and csiostor driver maintainer to review the series if it has not been done already. It would be great If I can include review comments from them in my next version of series. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html