From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH] IB/mthca: Fix how mthca_map_user_db() calls gup Date: Fri, 26 Jan 2018 10:44:28 -0500 Message-ID: <1516981468.27592.200.camel@redhat.com> References: <20180123205459.432-1-dave@stgolabs.net> <1516898063.27592.136.camel@redhat.com> <20180125175048.GG10706@ziepe.ca> <1516903584.27592.183.camel@redhat.com> <20180125185330.GH10706@ziepe.ca> <20180125192727.dkwuqel3xfut66wj@linux-n805> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-IrJSZj5Btdbj6ipVG5gZ" Return-path: In-Reply-To: <20180125192727.dkwuqel3xfut66wj@linux-n805> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Davidlohr Bueso , Jason Gunthorpe Cc: roland-BHEL68pLQRGGvPXPguhicg@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Davidlohr Bueso List-Id: linux-rdma@vger.kernel.org --=-IrJSZj5Btdbj6ipVG5gZ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, 2018-01-25 at 11:27 -0800, Davidlohr Bueso wrote: > On Thu, 25 Jan 2018, Jason Gunthorpe wrote: >=20 > > >=20 > > > Since the original post was referred to an ABBA deadlock, wouldn't we > > > have to drop db_tab->mutex, then grab both in the proper order? > >=20 > > I had understood that was only a concern because Davidlohr was having > > trouble proving the callchain didn't include mmap_sem already.. > >=20 > > I can see the call chain all ends on verbs ops, and I know verbs ops > > with ucontext's are never called under mmap_sem by the core code.. >=20 > Right. Ok so this simplifies things and we can just use gup_fast(). >=20 > Thanks, > Davidlohr Thanks, applied. --=20 Doug Ledford GPG KeyID: B826A3330E572FDD Key fingerprint =3D AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD --=-IrJSZj5Btdbj6ipVG5gZ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEErmsb2hIrI7QmWxJ0uCajMw5XL90FAlprTNwACgkQuCajMw5X L91b2A//R0K8QWltWlrcMP9gW0JVm8G/s5SrlCZAsR/S3X48ojiPG0tma9cZKrF5 Zj21/mUrL2m3deYF7qOHGyXYlADFy8Z/azHJDRMBK9/IbVsItoJ28sEDhjWbvhcx YlGe3jjwO+PgEms6Z8Zlo5cRlOyMH4pL/w2Q8Rw53sv+KMbSvT0zqXjip2cMVNOQ Wu9l6IhU48NwzTDnd5akp0wkaVi6W2GG88huEfvmSnBiB78wmZK0BN5UsviSvjFE y8KgXvLioQ7Xev0DrfuauxPfqoTOvngGJYyE21/8N+08cSEB2jGKiaAphJC5iEyN 2Q9/dcvFZmdrrVS7oQt8maczuXLOqsakVgxRjApbaV4/MnKQsanrr8qMg+w0B/Py QO/09AfufIeJ6ZpEJr57Tc2y8dmMKtTmWqGXgb7kLoXAPPgQeH4L/rkCcHmHIXro W/1VomVCrOm9Y0L7pyFavuvjbtLjEul7TOx+EqgFz4gY79EIYytRt3wbhTLynrwh JJgBDeWchgQQTGwuaPaEuhhwbU/JEJWUEM0nLOzZD/31GIyOXyKHxhDknr+86vIm kKchYdkA1/oZHyjfxHuXaGG8/obvYyBzV2blsSjoP1uXJuXuo03psKU9TQRvHUiv dPIj7KiHVl+InwIup7dyTcbTDAScFLh45239S1ly7NNJKQDcFxY= =Gqkv -----END PGP SIGNATURE----- --=-IrJSZj5Btdbj6ipVG5gZ-- -- 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