From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH 11/11] IB/srp: Prevent mapping failures Date: Mon, 25 Apr 2016 08:54:33 +0300 Message-ID: <20160425055433.GG7974@leon.nu> References: <571A936F.7040409@sandisk.com> <571A94AF.7000609@sandisk.com> <20160424083538.GF7974@leon.nu> <571D6975.2020905@sandisk.com> Reply-To: leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="XRI2XbIfl/05pQwm" Return-path: Content-Disposition: inline In-Reply-To: <571D6975.2020905-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche Cc: Doug Ledford , Christoph Hellwig , Sagi Grimberg , Laurence Oberman , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org --XRI2XbIfl/05pQwm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Apr 24, 2016 at 05:48:53PM -0700, Bart Van Assche wrote: > On 04/24/16 01:35, Leon Romanovsky wrote: > >On Fri, Apr 22, 2016 at 02:16:31PM -0700, Bart Van Assche wrote: > >>+ max_max_sectors =3D (srp_dev->max_pages_per_mr - 1) << > >>+ (ilog2(srp_dev->mr_page_size) - 9); > > > > From my understanding, srp_dev->max_pages_per_mr can be equal to 1, in > >case device will advertise it. > > > >Is this understanding correct? > >Will the code work in such case? >=20 > Hello Leon, >=20 > I'm not sure a HCA driver exists for which max_pages_per_mr =3D=3D 1. > Additionally, I'm not sure such a driver would be useful because such a > driver would limit the maximum data transfer size for the iSER protocol t= o 4 > KB. That is too low to reach good performance. Bart and Laurence, You are raising valuable arguments about sanity of setting srp_dev->max_pag= es_per_mr to be equal 1. I totally agree with you that it is insane, however my original question was "does the code support such value?" >=20 > Bart. >=20 > -- > 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 --XRI2XbIfl/05pQwm Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXHbEZAAoJEORje4g2clinVPMP/1xNLte1yusWm3tgdc44CtSp 9eehGeOXP7rRUpCv4MrXY4UTZOClm76qlrsDmmonSMTzH8aPJHJwOFEcmkKcuRhb 9+KZiYPEY16kQgk6Phh243qc6F33iB1pCIILvbfPVqZtetW1B4iyO3UUmkc7GwAg N2DmmZR+VUtVd94VFjJWNgholY+oj9CUfBRMsvRqlKB1JjTA8o4rvT/PrMiwaLje Hh4+ELvlNihsl9iveBKkYsNged9H9YttcXr/5qmVRcJenxTbkmIv7BwpxXLnw2Ip xZTLmxWcvzCG18Plf3WFU/A8IFaeOZl73ywyPg0JL26MRq6TPRvzjwvEweaNRThk fCYcx+oVVw6btc7LOZh4GPmYH4vZCLbODO1JFALQM6Z9DAbAQOlja8ao+fVVYGYs pBEQFydbmrIRxyYkka5Y6svZhu4x0+AOpVa933gjcZpWMc3nao4ZtxVz9cLvh8DP eWAYRl2sU1dRQQM2K+NszSdZ6MHZOI+IzXPtxT/OIDXDWdFXKzfa8EL6MlP2r1+3 i9e28Sfq7FyeHcl/vMhkKAWLmtEsURSnPeCTelukaDCPDxsXEL8JKL5IDvSuXGzZ ZMuPfOApjGEcvxsBdi1WJ11tBTktoc60ynTeHe0KI0MzRdn2Ha5Z6YFDUThC61jC 18sPi1ZbiN1FfxcSaqSA =8FVa -----END PGP SIGNATURE----- --XRI2XbIfl/05pQwm-- -- 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