From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26C4FC433EF for ; Tue, 28 Jun 2022 11:54:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344821AbiF1LyJ (ORCPT ); Tue, 28 Jun 2022 07:54:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344720AbiF1LyI (ORCPT ); Tue, 28 Jun 2022 07:54:08 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BAE530F7F for ; Tue, 28 Jun 2022 04:54:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3041860C50 for ; Tue, 28 Jun 2022 11:54:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3776C3411D; Tue, 28 Jun 2022 11:54:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656417246; bh=7Exp3uuDYftC1Kc9TUILgP5JAsyg22VZl4q5tvD5wbI=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Ec//1F1YD2L0Cc9RnovXioudDwi//vz3lVFTFbbIbISxIlB/gPRKuH5sQBk9Lnj32 j+9uPYHj68c7/jzbA3/z+XFUbPjYPRTNihtEYMdKxw/kXmoBp6C5grPQKQXtgStyB3 nXJHyrzK5nNJnLTIQthVUvDHIZbxn50IDcbZFiYh593+T3/zjkoiFpgDKoG7a34Iu8 kzarRbwCwyIBi0yyPu/ndwAA/AKbLWQezzmCPhDTgP5Jyagpcs/6thE+konO50A5v0 9pCGJ430lZpVLdZDT552DjIDS41h6G+MbjrL4C0Qo1V96KdpowT0/30tvjuASvEM6R h8PRpw6P2q3aA== Message-ID: <41e5ef1ad950f1d41fd8a46afaa34cf3ef660f9c.camel@kernel.org> Subject: Re: [PATCH 28/44] unify the rest of iov_iter_get_pages()/iov_iter_get_pages_alloc() guts From: Jeff Layton To: Al Viro , linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Jens Axboe , Christoph Hellwig , Matthew Wilcox , David Howells , Dominique Martinet , Christian Brauner Date: Tue, 28 Jun 2022 07:54:04 -0400 In-Reply-To: <20220622041552.737754-28-viro@zeniv.linux.org.uk> References: <20220622041552.737754-1-viro@zeniv.linux.org.uk> <20220622041552.737754-28-viro@zeniv.linux.org.uk> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.2 (3.44.2-1.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, 2022-06-22 at 05:15 +0100, Al Viro wrote: > same as for pipes and xarrays; after that iov_iter_get_pages() becomes > a wrapper for __iov_iter_get_pages_alloc(). >=20 > Signed-off-by: Al Viro > --- > lib/iov_iter.c | 86 ++++++++++++++++---------------------------------- > 1 file changed, 28 insertions(+), 58 deletions(-) >=20 > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index 07dacb274ba5..811fa09515d8 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -1372,20 +1372,19 @@ static struct page *first_bvec_segment(const stru= ct iov_iter *i, > return page; > } > =20 > -ssize_t iov_iter_get_pages(struct iov_iter *i, > - struct page **pages, size_t maxsize, unsigned maxpages, > - size_t *start) > +static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, > + struct page ***pages, size_t maxsize, > + unsigned int maxpages, size_t *start) > { > size_t len; > int n, res; > =20 > if (maxsize > i->count) > maxsize =3D i->count; > - if (!maxsize || !maxpages) > + if (!maxsize) > return 0;=20 > if (maxsize > MAX_RW_COUNT) > maxsize =3D MAX_RW_COUNT; > - BUG_ON(!pages); > =20 > if (likely(user_backed_iter(i))) { > unsigned int gup_flags =3D 0; > @@ -1398,80 +1397,51 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, > =20 > addr =3D first_iovec_segment(i, &len, start, maxsize, maxpages); > n =3D DIV_ROUND_UP(len, PAGE_SIZE); > - res =3D get_user_pages_fast(addr, n, gup_flags, pages); > + if (!*pages) { > + *pages =3D get_pages_array(n); > + if (!*pages) > + return -ENOMEM; > + } > + res =3D get_user_pages_fast(addr, n, gup_flags, *pages); > if (unlikely(res <=3D 0)) > return res; > return (res =3D=3D n ? len : res * PAGE_SIZE) - *start; > } > if (iov_iter_is_bvec(i)) { > + struct page **p; > struct page *page; > =20 > page =3D first_bvec_segment(i, &len, start, maxsize, maxpages); > n =3D DIV_ROUND_UP(len, PAGE_SIZE); > + p =3D *pages; > + if (!p) { > + *pages =3D p =3D get_pages_array(n); > + if (!p) > + return -ENOMEM; > + } > while (n--) > - get_page(*pages++ =3D page++); > + get_page(*p++ =3D page++); > return len - *start; > } > if (iov_iter_is_pipe(i)) > - return pipe_get_pages(i, &pages, maxsize, maxpages, start); > + return pipe_get_pages(i, pages, maxsize, maxpages, start); > if (iov_iter_is_xarray(i)) > - return iter_xarray_get_pages(i, &pages, maxsize, maxpages, start); > + return iter_xarray_get_pages(i, pages, maxsize, maxpages, > + start); > return -EFAULT; > } > -EXPORT_SYMBOL(iov_iter_get_pages); > =20 > -static ssize_t __iov_iter_get_pages_alloc(struct iov_iter *i, > - struct page ***pages, size_t maxsize, > +ssize_t iov_iter_get_pages(struct iov_iter *i, > + struct page **pages, size_t maxsize, unsigned maxpages, > size_t *start) > { > - struct page **p; > - size_t len; > - int n, res; > - > - if (maxsize > i->count) > - maxsize =3D i->count; > - if (!maxsize) > + if (!maxpages) > return 0; > - if (maxsize > MAX_RW_COUNT) > - maxsize =3D MAX_RW_COUNT; > - > - if (likely(user_backed_iter(i))) { > - unsigned int gup_flags =3D 0; > - unsigned long addr; > - > - if (iov_iter_rw(i) !=3D WRITE) > - gup_flags |=3D FOLL_WRITE; > - if (i->nofault) > - gup_flags |=3D FOLL_NOFAULT; > - > - addr =3D first_iovec_segment(i, &len, start, maxsize, ~0U); > - n =3D DIV_ROUND_UP(len, PAGE_SIZE); > - *pages =3D p =3D get_pages_array(n); > - if (!p) > - return -ENOMEM; > - res =3D get_user_pages_fast(addr, n, gup_flags, p); > - if (unlikely(res <=3D 0)) > - return res; > - return (res =3D=3D n ? len : res * PAGE_SIZE) - *start; > - } > - if (iov_iter_is_bvec(i)) { > - struct page *page; > + BUG_ON(!pages); > =20 > - page =3D first_bvec_segment(i, &len, start, maxsize, ~0U); > - n =3D DIV_ROUND_UP(len, PAGE_SIZE); > - *pages =3D p =3D get_pages_array(n); > - if (!p) > - return -ENOMEM; > - while (n--) > - get_page(*p++ =3D page++); > - return len - *start; > - } > - if (iov_iter_is_pipe(i)) > - return pipe_get_pages(i, pages, maxsize, ~0U, start); > - if (iov_iter_is_xarray(i)) > - return iter_xarray_get_pages(i, pages, maxsize, ~0U, start); > - return -EFAULT; > + return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); > } > +EXPORT_SYMBOL(iov_iter_get_pages); > =20 > ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, > struct page ***pages, size_t maxsize, > @@ -1481,7 +1451,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i= , > =20 > *pages =3D NULL; > =20 > - len =3D __iov_iter_get_pages_alloc(i, pages, maxsize, start); > + len =3D __iov_iter_get_pages_alloc(i, pages, maxsize, ~0U, start); > if (len <=3D 0) { > kvfree(*pages); > *pages =3D NULL; Reviewed-by: Jeff Layton