From patchwork Mon Sep 25 12:03:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13397739 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 60D9A18E0B for ; Mon, 25 Sep 2023 12:03:46 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B646197 for ; Mon, 25 Sep 2023 05:03:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1695643424; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ENB7CtH73xnlPC5Szfr84FelPyw0n3TXhDinmckBTOE=; b=AoTQ5wSF4OfFnRMd0QwJGAQWQont0S8cCI6JVx1cTRWSZx4NNhqZ9hEOiO5+qJFIHDtmEO wD53OtbhCumLAkDim6RYIcGKyscTqvyThLeWA/pePOVd416OXBm1N6YtZLYe1011XdxTxf 3Kfkb2LuESXGaaqpu9Nq/01FtZGS1ms= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-638-Tspro7EYNxWz9xyR8d5l5A-1; Mon, 25 Sep 2023 08:03:38 -0400 X-MC-Unique: Tspro7EYNxWz9xyR8d5l5A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 07FBD3C1E9D8; Mon, 25 Sep 2023 12:03:38 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.216]) by smtp.corp.redhat.com (Postfix) with ESMTP id 609BB14171B6; Mon, 25 Sep 2023 12:03:36 +0000 (UTC) From: David Howells To: Jens Axboe Cc: David Howells , Al Viro , Linus Torvalds , Christoph Hellwig , Christian Brauner , David Laight , Matthew Wilcox , Jeff Layton , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 08/12] iov_iter: Don't deal with iter->copy_mc in memcpy_from_iter_mc() Date: Mon, 25 Sep 2023 13:03:05 +0100 Message-ID: <20230925120309.1731676-9-dhowells@redhat.com> In-Reply-To: <20230925120309.1731676-1-dhowells@redhat.com> References: <20230925120309.1731676-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-Spam-Status: No, score=1.2 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL,RCVD_IN_SBL_CSS,SPF_HELO_NONE, SPF_NONE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: * X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net iter->copy_mc is only used with a bvec iterator and only by dump_emit_page() in fs/coredump.c so rather than handle this in memcpy_from_iter_mc() where it is checked repeatedly by _copy_from_iter() and copy_page_from_iter_atomic(), Signed-off-by: David Howells cc: Alexander Viro cc: Jens Axboe cc: Christoph Hellwig cc: Christian Brauner cc: Matthew Wilcox cc: Linus Torvalds cc: David Laight cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- lib/iov_iter.c | 39 +++++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 12 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 65374ee91ecd..943aa3cfd7b3 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -253,14 +253,33 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) EXPORT_SYMBOL_GPL(_copy_mc_to_iter); #endif /* CONFIG_ARCH_HAS_COPY_MC */ -static size_t memcpy_from_iter_mc(void *iter_from, size_t progress, - size_t len, void *to, void *priv2) +static __always_inline +size_t memcpy_from_iter_mc(void *iter_from, size_t progress, + size_t len, void *to, void *priv2) +{ + return copy_mc_to_kernel(to + progress, iter_from, len); +} + +static size_t __copy_from_iter_mc(void *addr, size_t bytes, struct iov_iter *i) { - struct iov_iter *iter = priv2; + size_t progress; - if (iov_iter_is_copy_mc(iter)) - return copy_mc_to_kernel(to + progress, iter_from, len); - return memcpy_from_iter(iter_from, progress, len, to, priv2); + if (unlikely(i->count < bytes)) + bytes = i->count; + if (unlikely(!bytes)) + return 0; + progress = iterate_bvec(i, bytes, addr, NULL, memcpy_from_iter_mc); + i->count -= progress; + return progress; +} + +static __always_inline +size_t __copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) +{ + if (unlikely(iov_iter_is_copy_mc(i))) + return __copy_from_iter_mc(addr, bytes, i); + return iterate_and_advance(i, bytes, addr, + copy_from_user_iter, memcpy_from_iter); } size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) @@ -270,9 +289,7 @@ size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) if (user_backed_iter(i)) might_fault(); - return iterate_and_advance2(i, bytes, addr, i, - copy_from_user_iter, - memcpy_from_iter_mc); + return __copy_from_iter(addr, bytes, i); } EXPORT_SYMBOL(_copy_from_iter); @@ -493,9 +510,7 @@ size_t copy_page_from_iter_atomic(struct page *page, size_t offset, } p = kmap_atomic(page) + offset; - n = iterate_and_advance2(i, n, p, i, - copy_from_user_iter, - memcpy_from_iter_mc); + __copy_from_iter(p, n, i); kunmap_atomic(p); copied += n; offset += n;