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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6929C48BD6 for ; Thu, 27 Jun 2019 07:47:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 79B8A205ED for ; Thu, 27 Jun 2019 07:47:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726416AbfF0Hre (ORCPT ); Thu, 27 Jun 2019 03:47:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47494 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726375AbfF0Hre (ORCPT ); Thu, 27 Jun 2019 03:47:34 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E1F153083391; Thu, 27 Jun 2019 07:47:33 +0000 (UTC) Received: from ming.t460p (ovpn-8-24.pek2.redhat.com [10.72.8.24]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 81E415D71C; Thu, 27 Jun 2019 07:47:25 +0000 (UTC) Date: Thu, 27 Jun 2019 15:47:21 +0800 From: Ming Lei To: Damien Le Moal Cc: linux-scsi@vger.kernel.org, "Martin K . Petersen" , linux-block@vger.kernel.org, Jens Axboe , Christoph Hellwig , Bart Van Assche Subject: Re: [PATCH V4 1/3] block: Allow mapping of vmalloc-ed buffers Message-ID: <20190627074720.GB24671@ming.t460p> References: <20190627024910.23987-1-damien.lemoal@wdc.com> <20190627024910.23987-2-damien.lemoal@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190627024910.23987-2-damien.lemoal@wdc.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.44]); Thu, 27 Jun 2019 07:47:34 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Jun 27, 2019 at 11:49:08AM +0900, Damien Le Moal wrote: > To allow the SCSI subsystem scsi_execute_req() function to issue > requests using large buffers that are better allocated with vmalloc() > rather than kmalloc(), modify bio_map_kern() and bio_copy_kern() to > allow passing a buffer allocated with vmalloc(). To do so, detect > vmalloc-ed buffers using is_vmalloc_addr(). For vmalloc-ed buffers, > flush the buffer using flush_kernel_vmap_range(), use vmalloc_to_page() > instead of virt_to_page() to obtain the pages of the buffer, and > invalidate the buffer addresses with invalidate_kernel_vmap_range() on > completion of read BIOs. This last point is executed using the function > bio_invalidate_vmalloc_pages() which is defined only if the > architecture defines ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE, that is, if the > architecture actually needs the invalidation done. > > Fixes: 515ce6061312 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation") > Fixes: e76239a3748c ("block: add a report_zones method") > Cc: stable@vger.kernel.org > Signed-off-by: Damien Le Moal > --- > block/bio.c | 43 ++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 42 insertions(+), 1 deletion(-) > > diff --git a/block/bio.c b/block/bio.c > index ce797d73bb43..1c21d1e7f1b8 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -16,6 +16,7 @@ > #include > #include > #include > +#include > > #include > #include "blk.h" > @@ -1479,8 +1480,26 @@ void bio_unmap_user(struct bio *bio) > bio_put(bio); > } > > +#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE > +static void bio_invalidate_vmalloc_pages(struct bio *bio) > +{ > + if (bio->bi_private) { > + struct bvec_iter_all iter_all; > + struct bio_vec *bvec; > + unsigned long len = 0; > + > + bio_for_each_segment_all(bvec, bio, iter_all) > + len += bvec->bv_len; > + invalidate_kernel_vmap_range(bio->bi_private, len); > + } > +} > +#else > +static void bio_invalidate_vmalloc_pages(struct bio *bio) {} > +#endif > + > static void bio_map_kern_endio(struct bio *bio) > { > + bio_invalidate_vmalloc_pages(bio); > bio_put(bio); > } > > @@ -1501,6 +1520,8 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, > unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; > unsigned long start = kaddr >> PAGE_SHIFT; > const int nr_pages = end - start; > + bool is_vmalloc = is_vmalloc_addr(data); > + struct page *page; > int offset, i; > struct bio *bio; > > @@ -1508,6 +1529,12 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, > if (!bio) > return ERR_PTR(-ENOMEM); > > + if (is_vmalloc) { > + flush_kernel_vmap_range(data, len); > + if ((!op_is_write(bio_op(bio)))) > + bio->bi_private = data; > + } > + > offset = offset_in_page(kaddr); > for (i = 0; i < nr_pages; i++) { > unsigned int bytes = PAGE_SIZE - offset; > @@ -1518,7 +1545,11 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, > if (bytes > len) > bytes = len; > > - if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, > + if (!is_vmalloc) > + page = virt_to_page(data); > + else > + page = vmalloc_to_page(data); > + if (bio_add_pc_page(q, bio, page, bytes, > offset) < bytes) { > /* we don't support partial mappings */ > bio_put(bio); > @@ -1531,6 +1562,7 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, > } > > bio->bi_end_io = bio_map_kern_endio; > + > return bio; > } > EXPORT_SYMBOL(bio_map_kern); > @@ -1543,6 +1575,7 @@ static void bio_copy_kern_endio(struct bio *bio) > > static void bio_copy_kern_endio_read(struct bio *bio) > { > + unsigned long len = 0; > char *p = bio->bi_private; > struct bio_vec *bvec; > struct bvec_iter_all iter_all; > @@ -1550,8 +1583,12 @@ static void bio_copy_kern_endio_read(struct bio *bio) > bio_for_each_segment_all(bvec, bio, iter_all) { > memcpy(p, page_address(bvec->bv_page), bvec->bv_len); > p += bvec->bv_len; > + len += bvec->bv_len; > } > > + if (is_vmalloc_addr(bio->bi_private)) > + invalidate_kernel_vmap_range(bio->bi_private, len); > + > bio_copy_kern_endio(bio); > } > > @@ -1572,6 +1609,7 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, > unsigned long kaddr = (unsigned long)data; > unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; > unsigned long start = kaddr >> PAGE_SHIFT; > + bool is_vmalloc = is_vmalloc_addr(data); > struct bio *bio; > void *p = data; > int nr_pages = 0; > @@ -1587,6 +1625,9 @@ struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, > if (!bio) > return ERR_PTR(-ENOMEM); > > + if (is_vmalloc) > + flush_kernel_vmap_range(data, len); > + Are your sure that invalidate[|flush]_kernel_vmap_range is needed for bio_copy_kernel? The vmalloc buffer isn't involved in IO, and only accessed by CPU. Thanks, Ming