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 E70ACC43334 for ; Tue, 28 Jun 2022 12:07:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239617AbiF1MHc (ORCPT ); Tue, 28 Jun 2022 08:07:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238286AbiF1MHb (ORCPT ); Tue, 28 Jun 2022 08:07:31 -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 D6EC8255BB for ; Tue, 28 Jun 2022 05:06:49 -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 0735C60F06 for ; Tue, 28 Jun 2022 12:06:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85C8AC3411D; Tue, 28 Jun 2022 12:06:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656418008; bh=uJS87uGYaWdDsDyiKOcr19tMBMsRj3d8CYlsOmYR/74=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=hLiWR9XpF0oCC8PtWPhcLoiVIH8V40M/o5w43OZGZScDnaXbZRG/Lo3NCOPjZo5oC ZS9D3o51PTdBa/aWYOxALpvbANaglYVJ/pLADqMv1yDlMyA/TC4bgGygmQd4KnZ+Y1 aTTY3AYoZCkBj/XjuPQfczaaJCfyMEC8eBI6RZnmlS7YMXEkLSCpVNNI1eIYR8RYpM vk1MxrHs6cFwy0MUFBh6vH9MR4tT96YP4JVfTz1ouef8Ov0VDPze+a/ovMrOBRlmBE BY9SGkmxMMWjXdr9z120J3VWc2OCxbaUV5w+Nn9w6vAlWpR3+ZB+2pzbmtiIk14gCn 51p/uDVm7cMag== Message-ID: Subject: Re: [PATCH 32/44] iov_iter: massage calling conventions for first_{iovec,bvec}_segment() 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 08:06:46 -0400 In-Reply-To: <20220622041552.737754-32-viro@zeniv.linux.org.uk> References: <20220622041552.737754-1-viro@zeniv.linux.org.uk> <20220622041552.737754-32-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: > Pass maxsize by reference, return length via the same. >=20 > Signed-off-by: Al Viro > --- > lib/iov_iter.c | 37 +++++++++++++++---------------------- > 1 file changed, 15 insertions(+), 22 deletions(-) >=20 > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index 0bed684d91d0..fca66ecce7a0 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -1306,26 +1306,22 @@ static ssize_t iter_xarray_get_pages(struct iov_i= ter *i, > return min_t(size_t, nr * PAGE_SIZE - offset, maxsize); > } > =20 > -static unsigned long found_ubuf_segment(unsigned long addr, > - size_t len, > - size_t *size, size_t *start) > +static unsigned long found_ubuf_segment(unsigned long addr, size_t *star= t) > { > *start =3D addr % PAGE_SIZE; > - *size =3D len; > return addr & PAGE_MASK; > } > =20 > /* must be done on non-empty ITER_UBUF or ITER_IOVEC one */ > static unsigned long first_iovec_segment(const struct iov_iter *i, > - size_t *size, size_t *start, > - size_t maxsize) > + size_t *size, size_t *start) > { > size_t skip; > long k; > =20 > if (iter_is_ubuf(i)) { > unsigned long addr =3D (unsigned long)i->ubuf + i->iov_offset; > - return found_ubuf_segment(addr, maxsize, size, start); > + return found_ubuf_segment(addr, start); > } > =20 > for (k =3D 0, skip =3D i->iov_offset; k < i->nr_segs; k++, skip =3D 0) = { > @@ -1334,28 +1330,26 @@ static unsigned long first_iovec_segment(const st= ruct iov_iter *i, > =20 > if (unlikely(!len)) > continue; > - if (len > maxsize) > - len =3D maxsize; > - return found_ubuf_segment(addr, len, size, start); > + if (*size > len) > + *size =3D len; > + return found_ubuf_segment(addr, start); > } > BUG(); // if it had been empty, we wouldn't get called > } > =20 > /* must be done on non-empty ITER_BVEC one */ > static struct page *first_bvec_segment(const struct iov_iter *i, > - size_t *size, size_t *start, > - size_t maxsize) > + size_t *size, size_t *start) > { > struct page *page; > size_t skip =3D i->iov_offset, len; > =20 > len =3D i->bvec->bv_len - skip; > - if (len > maxsize) > - len =3D maxsize; > + if (*size > len) > + *size =3D len; > skip +=3D i->bvec->bv_offset; > page =3D i->bvec->bv_page + skip / PAGE_SIZE; > *start =3D skip % PAGE_SIZE; > - *size =3D len; > return page; > } > =20 > @@ -1363,7 +1357,6 @@ static ssize_t __iov_iter_get_pages_alloc(struct io= v_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) > @@ -1382,8 +1375,8 @@ static ssize_t __iov_iter_get_pages_alloc(struct io= v_iter *i, > if (i->nofault) > gup_flags |=3D FOLL_NOFAULT; > =20 > - addr =3D first_iovec_segment(i, &len, start, maxsize); > - n =3D DIV_ROUND_UP(len + *start, PAGE_SIZE); > + addr =3D first_iovec_segment(i, &maxsize, start); > + n =3D DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); > if (n > maxpages) > n =3D maxpages; > if (!*pages) { > @@ -1394,14 +1387,14 @@ static ssize_t __iov_iter_get_pages_alloc(struct = iov_iter *i, > res =3D get_user_pages_fast(addr, n, gup_flags, *pages); > if (unlikely(res <=3D 0)) > return res; > - return min_t(size_t, len, res * PAGE_SIZE - *start); > + return min_t(size_t, maxsize, 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); > - n =3D DIV_ROUND_UP(len + *start, PAGE_SIZE); > + page =3D first_bvec_segment(i, &maxsize, start); > + n =3D DIV_ROUND_UP(maxsize + *start, PAGE_SIZE); > if (n > maxpages) > n =3D maxpages; > p =3D *pages; > @@ -1412,7 +1405,7 @@ static ssize_t __iov_iter_get_pages_alloc(struct io= v_iter *i, > } > for (int k =3D 0; k < n; k++) > get_page(*p++ =3D page++); > - return min_t(size_t, len, n * PAGE_SIZE - *start); > + return min_t(size_t, maxsize, n * PAGE_SIZE - *start); > } > if (iov_iter_is_pipe(i)) > return pipe_get_pages(i, pages, maxsize, maxpages, start); Reviewed-by: Jeff Layton