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 184FE23AB81 for ; Thu, 30 Apr 2026 08:19:09 +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=1777537150; cv=none; b=jcwVAJftY3bCivhwAIuy2/1EtYuMNhx0HtDVcoq+SkS8zGipki/xt38L+9LSCYMwehuWGQUgPipeZNPSZa+yeLVhBHye+JB4Bem7m83reolhsnIgB6nwcQCku9Na7yvXmbNtMuYzRthrlKsvYuTK93CA8+c5EwZRNIiL2cjiY6g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777537150; c=relaxed/simple; bh=nHo+/9OPreuHPaTVBBmuUZuduI9RsjnvcQGNAo1H/A8=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=a5VQuOL4+ZWAA5JU6CXse81bUhrdTJYHtqYcJqZhrF/ZSmQeN+eWD9RM6pBIJFG/2iakRc5/eaLDBijfRkWvdG+6Swb8bljKaiebiDJfMPJoGSZi0L5ZRP4lP0rdzOVnLJ9tgtIyQTKNwDWQyjJb/ERWyITvISNmapCC2+ycWTQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oUyT0Aiu; 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="oUyT0Aiu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3069AC2BCB3; Thu, 30 Apr 2026 08:19:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777537149; bh=nHo+/9OPreuHPaTVBBmuUZuduI9RsjnvcQGNAo1H/A8=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=oUyT0AiukyQBBiEZUD9dk9O1uQNxm1iMwZMUbugSEDv4lTUURMgsCt/wiKrq4AbCI hl89tvrv+KeSHmTnI2NOQ03xzOkQnaCYF87hM9AprlCeUO1gQDtwnr5XGlJSGZjVwt 3us/nx2CDtc29VCApFFNHXgug94dpssqcynS5W1s01JajmkuXd/UbrDYkSxtOYlHTn CBQLMolK0zXK0BJQ+PJ8EP5zUIDrBu0FmiQYLDnqQaqI8eNBDg1dWbMdAT8KFw9TUA 37V7303pLmIA2Hn6FDZ32FJheLOzbZXSFyBMOJ6G4Hvs4Jte28ePBS+M+39vCmlriw cxhAnX5oux4jw== Message-ID: <98de5c670d5b46c294513f10d698039a0b061459.camel@kernel.org> Subject: Re: [PATCH v2 06/14] fuse: support buffer copying for kernel addresses From: Jeff Layton To: Joanne Koong , miklos@szeredi.hu Cc: bernd@bsbernd.com, axboe@kernel.dk, linux-fsdevel@vger.kernel.org Date: Thu, 30 Apr 2026 09:19:05 +0100 In-Reply-To: <20260402162840.2989717-7-joannelkoong@gmail.com> References: <20260402162840.2989717-1-joannelkoong@gmail.com> <20260402162840.2989717-7-joannelkoong@gmail.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Thu, 2026-04-02 at 09:28 -0700, Joanne Koong wrote: > This is a preparatory patch needed to support pinned buffers in > fuse-over-io-uring. For pinned buffers, we get the vmapped address of > the buffer, which we can directly use with memcpy. >=20 > Currently, buffer copying in fuse only supports extracting underlying > pages from an iov iter and kmapping them. This commit allows buffer > copying to work directly on a kaddr. >=20 > Signed-off-by: Joanne Koong > Reviewed-by: Bernd Schubert > --- > fs/fuse/dev.c | 23 +++++++++++++++++++---- > fs/fuse/fuse_dev_i.h | 7 ++++++- > 2 files changed, 25 insertions(+), 5 deletions(-) >=20 > diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c > index 0b0241f47170..a87939eaa103 100644 > --- a/fs/fuse/dev.c > +++ b/fs/fuse/dev.c > @@ -848,6 +848,9 @@ void fuse_copy_init(struct fuse_copy_state *cs, bool = write, > /* Unmap and put previous page of userspace buffer */ > void fuse_copy_finish(struct fuse_copy_state *cs) > { > + if (cs->is_kaddr) > + return; > + > if (cs->currbuf) { > struct pipe_buffer *buf =3D cs->currbuf; > =20 > @@ -873,6 +876,12 @@ static int fuse_copy_fill(struct fuse_copy_state *cs= ) > struct page *page; > int err; > =20 > + if (cs->is_kaddr) { > + if (!cs->len) > + return -ENOBUFS; > + return 0; > + } > + > err =3D unlock_request(cs->req); > if (err) > return err; > @@ -931,15 +940,21 @@ static int fuse_copy_do(struct fuse_copy_state *cs,= void **val, unsigned *size) > { > unsigned ncpy =3D min(*size, cs->len); > if (val) { > - void *pgaddr =3D kmap_local_page(cs->pg); > - void *buf =3D pgaddr + cs->offset; > + void *pgaddr, *buf; > + > + if (!cs->is_kaddr) { > + pgaddr =3D kmap_local_page(cs->pg); > + buf =3D pgaddr + cs->offset; > + } else { > + buf =3D cs->kaddr + cs->offset; > + } > =20 > if (cs->write) > memcpy(buf, *val, ncpy); > else > memcpy(*val, buf, ncpy); > - > - kunmap_local(pgaddr); > + if (!cs->is_kaddr) > + kunmap_local(pgaddr); > *val +=3D ncpy; > } > *size -=3D ncpy; > diff --git a/fs/fuse/fuse_dev_i.h b/fs/fuse/fuse_dev_i.h > index 134bf44aff0d..aa1d25421054 100644 > --- a/fs/fuse/fuse_dev_i.h > +++ b/fs/fuse/fuse_dev_i.h > @@ -28,12 +28,17 @@ struct fuse_copy_state { > struct pipe_buffer *currbuf; > struct pipe_inode_info *pipe; > unsigned long nr_segs; > - struct page *pg; > + union { > + struct page *pg; > + void *kaddr; > + }; > unsigned int len; > unsigned int offset; > bool write:1; > bool move_folios:1; > bool is_uring:1; > + /* if set, use kaddr; otherwise use pg */ > + bool is_kaddr:1; > struct { > unsigned int copied_sz; /* copied size into the user buffer */ > } ring; Reviewed-by: Jeff Layton