From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2AB3281AD7 for ; Fri, 6 Dec 2024 05:40:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733463638; cv=none; b=Bwnh4vdRXHshjoD3BET6xoY8SGOs6sMTJhjmtNltmPvNftP/Wl2D8o1Tat3Kbunap3pDH+SW2ThQRnQNMgQ6B7OZ3/oxCgKMjIGjRWFHFnlz1MN6PenXKV785sZD6NlOX24qBPeysgE20r4pLjxRfitnNNo0NG7XWu9WLbUD6GY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733463638; c=relaxed/simple; bh=81Vzg3x+oFTXblD5AyM3DKGzK2KumEZhfqowMhRek2I=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=rIK60y1Tjj2K6BlTSUVd+VZw+i1RueG3wqopGAQH6eefuOSG8mWdHlgRLibiLbDpYOrZxtI5SOQ2WonuZhaajcvdZCQPxEF1RznyBHRIMBBrrP8kja7WTdYMEGhS0oZ/Ru4lpVJH3/GuYW9KaVVgCyBq8P0pK/s0lbb5llDcsFo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vz99sNYB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vz99sNYB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72277C4CED1; Fri, 6 Dec 2024 05:40:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733463637; bh=81Vzg3x+oFTXblD5AyM3DKGzK2KumEZhfqowMhRek2I=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Vz99sNYByg1CzWTCtG5fop0t47SdnndKcy7MTGCutvWbLFhFN85QDHIOWxHTAffdm lv4DUp7R0se9ErHfFDzTVoi8SB0iRA4IX1M0AJai3RnlrGtIx++2oMhjy0ol3qOB0F FYzwwvbkjBE/FH6HVGvqSIERXsJaGsBfWdnFaXnsfAblOZjKyTPy7LcHWjiiJh47Xd 8eodNkHKEziELhbnP06yLR6FEIxSeCfHGcWGoGNeVN8Z178IkeKKtmQZhVw1aMZXrJ 7gkt4cSqYOWkftnZMq3hwPe0SNVSOva64suVVYW9WEws7sGM5LmsIDbN6roCPfe4Ax uAcVGh+myA/+Q== Message-ID: <36a543b848e59ddf26c85d0c79b7e377d865a0af.camel@kernel.org> Subject: Re: [PATCH 1/2] nfsd: use new wake_up_var interfaces. From: Jeff Layton To: NeilBrown , Chuck Lever Cc: linux-nfs@vger.kernel.org, Olga Kornievskaia , Dai Ngo , Tom Talpey Date: Thu, 05 Dec 2024 21:40:36 -0800 In-Reply-To: <20241206025723.3537777-2-neilb@suse.de> References: <20241206025723.3537777-1-neilb@suse.de> <20241206025723.3537777-2-neilb@suse.de> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf 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Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.4 (3.52.4-2.fc40) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2024-12-06 at 13:55 +1100, NeilBrown wrote: > The wake_up_var interface is fragile as barriers are sometimes needed. > There are now new interfaces so that most wake-ups can use an interface > that is guaranteed to have all barriers needed. >=20 > This patch changes the wake up on cl_cb_inflight to use > atomic_dec_and_wake_up(). >=20 > It also changes the wake up on rp_locked to use store_release_wake_up(). > This involves changing rp_locked from atomic_t to int. >=20 > Signed-off-by: NeilBrown > --- > fs/nfsd/nfs4callback.c | 3 +-- > fs/nfsd/nfs4state.c | 16 ++++++---------- > fs/nfsd/state.h | 2 +- > 3 files changed, 8 insertions(+), 13 deletions(-) >=20 > diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c > index 3877b53e429f..a8dc9de2f7fb 100644 > --- a/fs/nfsd/nfs4callback.c > +++ b/fs/nfsd/nfs4callback.c > @@ -1036,8 +1036,7 @@ static void nfsd41_cb_inflight_begin(struct nfs4_cl= ient *clp) > static void nfsd41_cb_inflight_end(struct nfs4_client *clp) > { > =20 > - if (atomic_dec_and_test(&clp->cl_cb_inflight)) > - wake_up_var(&clp->cl_cb_inflight); > + atomic_dec_and_wake_up(&clp->cl_cb_inflight); > } > =20 > static void nfsd41_cb_inflight_wait_complete(struct nfs4_client *clp) > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 741b9449f727..9fbf7c8f0a3e 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -4739,7 +4739,7 @@ static void init_nfs4_replay(struct nfs4_replay *rp= ) > rp->rp_status =3D nfserr_serverfault; > rp->rp_buflen =3D 0; > rp->rp_buf =3D rp->rp_ibuf; > - atomic_set(&rp->rp_locked, RP_UNLOCKED); > + rp->rp_locked =3D RP_UNLOCKED; > } > =20 > static int nfsd4_cstate_assign_replay(struct nfsd4_compound_state *cstat= e, > @@ -4747,9 +4747,9 @@ static int nfsd4_cstate_assign_replay(struct nfsd4_= compound_state *cstate, > { > if (!nfsd4_has_session(cstate)) { > wait_var_event(&so->so_replay.rp_locked, > - atomic_cmpxchg(&so->so_replay.rp_locked, > - RP_UNLOCKED, RP_LOCKED) !=3D RP_LOCKED); > - if (atomic_read(&so->so_replay.rp_locked) =3D=3D RP_UNHASHED) > + cmpxchg(&so->so_replay.rp_locked, > + RP_UNLOCKED, RP_LOCKED) !=3D RP_LOCKED); nit: try_cmpxchg() generates more efficient assembly. Can we switch to that here too? > + if (so->so_replay.rp_locked =3D=3D RP_UNHASHED) > return -EAGAIN; > cstate->replay_owner =3D nfs4_get_stateowner(so); > } > @@ -4762,9 +4762,7 @@ void nfsd4_cstate_clear_replay(struct nfsd4_compoun= d_state *cstate) > =20 > if (so !=3D NULL) { > cstate->replay_owner =3D NULL; > - atomic_set(&so->so_replay.rp_locked, RP_UNLOCKED); > - smp_mb__after_atomic(); > - wake_up_var(&so->so_replay.rp_locked); > + store_release_wake_up(&so->so_replay.rp_locked, RP_UNLOCKED); > nfs4_put_stateowner(so); > } > } > @@ -5069,9 +5067,7 @@ move_to_close_lru(struct nfs4_ol_stateid *s, struct= net *net) > * Some threads with a reference might be waiting for rp_locked, > * so tell them to stop waiting. > */ > - atomic_set(&oo->oo_owner.so_replay.rp_locked, RP_UNHASHED); > - smp_mb__after_atomic(); > - wake_up_var(&oo->oo_owner.so_replay.rp_locked); > + store_release_wake_up(&oo->oo_owner.so_replay.rp_locked, RP_UNHASHED); > wait_event(close_wq, refcount_read(&s->st_stid.sc_count) =3D=3D 2); > =20 > release_all_access(s); > diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h > index e16bb3717fb9..ba30b2335b66 100644 > --- a/fs/nfsd/state.h > +++ b/fs/nfsd/state.h > @@ -505,7 +505,7 @@ struct nfs4_replay { > unsigned int rp_buflen; > char *rp_buf; > struct knfsd_fh rp_openfh; > - atomic_t rp_locked; > + int rp_locked; > char rp_ibuf[NFSD4_REPLAY_ISIZE]; > }; > =20 Looks good otherwise. Reviewed-by: Jeff Layton