From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by kanga.kvack.org (Postfix) with ESMTP id 951F18E0001 for ; Mon, 21 Jan 2019 10:02:04 -0500 (EST) Received: by mail-pg1-f198.google.com with SMTP id a2so14280128pgt.11 for ; Mon, 21 Jan 2019 07:02:04 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id c19si12423978pls.242.2019.01.21.07.02.01 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 21 Jan 2019 07:02:01 -0800 (PST) Date: Mon, 21 Jan 2019 07:02:00 -0800 From: Christoph Hellwig Subject: Re: [PATCH] Add kv_to_page() Message-ID: <20190121150200.GA14806@infradead.org> References: <20190121003944.GA26866@bombadil.infradead.org> <20190121093739.GA19725@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190121093739.GA19725@rapoport-lnx> Sender: owner-linux-mm@kvack.org List-ID: To: Mike Rapoport Cc: Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org > > diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c > > index d594f7520b7b..46326de4d9fe 100644 > > --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c > > +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c > > @@ -308,10 +308,7 @@ static struct dma_page *__ttm_dma_alloc_page(struct dma_pool *pool) > > vaddr = dma_alloc_attrs(pool->dev, pool->size, &d_page->dma, > > pool->gfp_flags, attrs); > > if (vaddr) { > > - if (is_vmalloc_addr(vaddr)) > > - d_page->p = vmalloc_to_page(vaddr); > > - else > > - d_page->p = virt_to_page(vaddr); > > + d_page->p = kv_to_page(vaddr); > > d_page->vaddr = (unsigned long)vaddr; This code doesn't need cosmetic cleanup but a real fix. Calling either vmalloc_to_page OR virt_to_page on the return value of dma_alloc_* is not allowed, an will break for many of the implementations. > > +++ b/drivers/md/bcache/util.c > > @@ -244,10 +244,7 @@ void bch_bio_map(struct bio *bio, void *base) > > start: bv->bv_len = min_t(size_t, PAGE_SIZE - bv->bv_offset, > > size); > > if (base) { > > - bv->bv_page = is_vmalloc_addr(base) > > - ? vmalloc_to_page(base) > > - : virt_to_page(base); > > - > > + bv->bv_page = kv_to_page(base); > > base += bv->bv_len; > > } This one also is broken, although not quite as badly. Anyone using vmalloc-like memory for bios need to call invalidate_kernel_vmap_range / flush_kernel_vmap_range to maintain cache coherency for VIVT caches. It seems this odd bcache API just makes it way to easy to miss that. > > @@ -403,23 +402,14 @@ static int scif_create_remote_lookup(struct scif_dev *remote_dev, > > goto error_window; > > } > > > > - vmalloc_dma_phys = is_vmalloc_addr(&window->dma_addr[0]); > > - vmalloc_num_pages = is_vmalloc_addr(&window->num_pages[0]); > > - > > /* Now map each of the pages containing physical addresses */ > > for (i = 0, j = 0; i < nr_pages; i += SCIF_NR_ADDR_IN_PAGE, j++) { > > err = scif_map_page(&window->dma_addr_lookup.lookup[j], > > - vmalloc_dma_phys ? > > - vmalloc_to_page(&window->dma_addr[i]) : > > - virt_to_page(&window->dma_addr[i]), > > - remote_dev); > > + kv_to_page(&window->dma_addr[i]), remote_dev); Similar issue here. We can't just DMA map pages returned from vmalloc_to_page without very explicit cache maintainance. > > pinned_pages->map_flags = SCIF_MAP_KERNEL; > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > > index 9a7def7c3237..1382cc18e7db 100644 > > --- a/drivers/spi/spi.c > > +++ b/drivers/spi/spi.c > > @@ -833,10 +833,7 @@ int spi_map_buf(struct spi_controller *ctlr, struct device *dev, > > min = min_t(size_t, desc_len, > > min_t(size_t, len, > > PAGE_SIZE - offset_in_page(buf))); > > - if (vmalloced_buf) > > - vm_page = vmalloc_to_page(buf); > > - else > > - vm_page = kmap_to_page(buf); > > + vm_page = kv_to_page(buf); Same issue here again :( > > diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c > > index 5d6724cee38f..4e13e88dd38c 100644 > > --- a/net/ceph/crypto.c > > +++ b/net/ceph/crypto.c > > @@ -191,11 +191,7 @@ static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg, > > struct page *page; > > unsigned int len = min(chunk_len - off, buf_len); > > > > - if (is_vmalloc) > > - page = vmalloc_to_page(buf); > > - else > > - page = virt_to_page(buf); > > - > > + page = kv_to_page(buf); > > sg_set_page(sg, page, len, off); Another issue of the same kind. > > > > -static inline struct page * __pure pgv_to_page(void *addr) > > -{ > > - if (is_vmalloc_addr(addr)) > > - return vmalloc_to_page(addr); > > - return virt_to_page(addr); > > -} This one plays really odd flush_dcache_page games, which looks like a workaround for the above proper APIs.