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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 7E601C4363C for ; Sun, 4 Oct 2020 15:44:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C2552078E for ; Sun, 4 Oct 2020 15:44:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601826245; bh=cMP0wpbyjV/IgdoWA8GFyhNdFCLseQ+W1zGduoOqTuo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tHM93miViPMedcFKgDJLQoQxLk0Jk5ST4DExNWCT7td8oWq78q9+uSWIZBNoHUoU8 aXLyJmnlUtUe8hfSEvBeOxRm5OVD1Pmzz57GdHvAUeIbikEoLB4sMg04ydpi6SmjIv OzOeYN9QFE8EXEJNY3fZoppPI8lhDkRC58tGeJ5s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726039AbgJDPoD (ORCPT ); Sun, 4 Oct 2020 11:44:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:57796 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726016AbgJDPn6 (ORCPT ); Sun, 4 Oct 2020 11:43:58 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0EC0B20735; Sun, 4 Oct 2020 15:43:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601826237; bh=cMP0wpbyjV/IgdoWA8GFyhNdFCLseQ+W1zGduoOqTuo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XazOb65HVrgpSmRiSceGVm2q2yryjkuepf6G/LXWO3qkAed580vQdH/mipD4PuegF E53dn5FKQvLWWTLFCuaoeH/vA5eSNH9zogmj30fOer4bumH3qf5xdDAiR32ZZUlI0n 9OV/g8m2C4KMPBK5spl4CUf85NhIQj1X+Od66oio= From: Leon Romanovsky To: Doug Ledford , Jason Gunthorpe Cc: Maor Gottlieb , Christoph Hellwig , Daniel Vetter , David Airlie , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Jani Nikula , Joonas Lahtinen , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, Rodrigo Vivi , Roland Scheidegger , Tvrtko Ursulin , VMware Graphics Subject: [PATCH rdma-next v5 1/4] lib/scatterlist: Add support in dynamic allocation of SG table from pages Date: Sun, 4 Oct 2020 18:43:37 +0300 Message-Id: <20201004154340.1080481-2-leon@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201004154340.1080481-1-leon@kernel.org> References: <20201004154340.1080481-1-leon@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: Maor Gottlieb Extend __sg_alloc_table_from_pages to support dynamic allocation of SG table from pages. It should be used by drivers that can't supply all the pages at one time. This function returns the last populated SGE in the table. Users should pass it as an argument to the function from the second call and forward. As before, nents will be equal to the number of populated SGEs (chunks). With this new extension, drivers can benefit the optimization of merging contiguous pages without a need to allocate all pages in advance and hold them in a large buffer. E.g. with the Infiniband driver that allocates a single page for hold the pages. For 1TB memory registration, the temporary buffer would consume only 4KB, instead of 2GB. Signed-off-by: Maor Gottlieb Reviewed-by: Christoph Hellwig Signed-off-by: Leon Romanovsky --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 +- drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 15 ++- include/linux/scatterlist.h | 38 +++--- lib/scatterlist.c | 125 ++++++++++++++++---- tools/testing/scatterlist/main.c | 9 +- 5 files changed, 142 insertions(+), 57 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index 12b30075134a..f2eaed6aca3d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -403,6 +403,7 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, unsigned int max_segment = i915_sg_segment_size(); struct sg_table *st; unsigned int sg_page_sizes; + struct scatterlist *sg; int ret; st = kmalloc(sizeof(*st), GFP_KERNEL); @@ -410,13 +411,12 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOMEM); alloc_table: - ret = __sg_alloc_table_from_pages(st, pvec, num_pages, - 0, num_pages << PAGE_SHIFT, - max_segment, - GFP_KERNEL); - if (ret) { + sg = __sg_alloc_table_from_pages(st, pvec, num_pages, 0, + num_pages << PAGE_SHIFT, max_segment, + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { kfree(st); - return ERR_PTR(ret); + return ERR_CAST(sg); } ret = i915_gem_gtt_prepare_pages(obj, st); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c index ab524ab3b0b4..f22acd398b1f 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c @@ -419,6 +419,7 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) int ret = 0; static size_t sgl_size; static size_t sgt_size; + struct scatterlist *sg; if (vmw_tt->mapped) return 0; @@ -441,13 +442,15 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) if (unlikely(ret != 0)) return ret; - ret = __sg_alloc_table_from_pages - (&vmw_tt->sgt, vsgt->pages, vsgt->num_pages, 0, - (unsigned long) vsgt->num_pages << PAGE_SHIFT, - dma_get_max_seg_size(dev_priv->dev->dev), - GFP_KERNEL); - if (unlikely(ret != 0)) + sg = __sg_alloc_table_from_pages(&vmw_tt->sgt, vsgt->pages, + vsgt->num_pages, 0, + (unsigned long) vsgt->num_pages << PAGE_SHIFT, + dma_get_max_seg_size(dev_priv->dev->dev), + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { + ret = PTR_ERR(sg); goto out_sg_alloc_fail; + } if (vsgt->num_pages > vmw_tt->sgt.nents) { uint64_t over_alloc = diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 45cf7b69d852..36c47e7e66a2 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -165,6 +165,22 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, #define for_each_sgtable_dma_sg(sgt, sg, i) \ for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) +static inline void __sg_chain(struct scatterlist *chain_sg, + struct scatterlist *sgl) +{ + /* + * offset and length are unused for chain entry. Clear them. + */ + chain_sg->offset = 0; + chain_sg->length = 0; + + /* + * Set lowest bit to indicate a link pointer, and make sure to clear + * the termination bit if it happens to be set. + */ + chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; +} + /** * sg_chain - Chain two sglists together * @prv: First scatterlist @@ -178,18 +194,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, struct scatterlist *sgl) { - /* - * offset and length are unused for chain entry. Clear them. - */ - prv[prv_nents - 1].offset = 0; - prv[prv_nents - 1].length = 0; - - /* - * Set lowest bit to indicate a link pointer, and make sure to clear - * the termination bit if it happens to be set. - */ - prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN) - & ~SG_END; + __sg_chain(&prv[prv_nents - 1], sgl); } /** @@ -286,10 +291,11 @@ void sg_free_table(struct sg_table *); int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask); +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask); int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 5d63a8857f36..e102fdfaa75b 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -365,6 +365,37 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) } EXPORT_SYMBOL(sg_alloc_table); +static struct scatterlist *get_next_sg(struct sg_table *table, + struct scatterlist *cur, + unsigned long needed_sges, + gfp_t gfp_mask) +{ + struct scatterlist *new_sg, *next_sg; + unsigned int alloc_size; + + if (cur) { + next_sg = sg_next(cur); + /* Check if last entry should be keeped for chainning */ + if (!sg_is_last(next_sg) || needed_sges == 1) + return next_sg; + } + + alloc_size = min_t(unsigned long, needed_sges, SG_MAX_SINGLE_ALLOC); + new_sg = sg_kmalloc(alloc_size, gfp_mask); + if (!new_sg) + return ERR_PTR(-ENOMEM); + sg_init_table(new_sg, alloc_size); + if (cur) { + __sg_chain(next_sg, new_sg); + table->orig_nents += alloc_size - 1; + } else { + table->sgl = new_sg; + table->orig_nents = alloc_size; + table->nents = 0; + } + return new_sg; +} + /** * __sg_alloc_table_from_pages - Allocate and initialize an sg table from * an array of pages @@ -374,29 +405,63 @@ EXPORT_SYMBOL(sg_alloc_table); * @offset: Offset from start of the first page to the start of a buffer * @size: Number of valid bytes in the buffer (after offset) * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) + * @prv: Last populated sge in sgt + * @left_pages: Left pages caller have to set after this call * @gfp_mask: GFP allocation mask * - * Description: - * Allocate and initialize an sg table from a list of pages. Contiguous - * ranges of the pages are squashed into a single scatterlist node up to the - * maximum size specified in @max_segment. An user may provide an offset at a - * start and a size of valid data in a buffer specified by the page array. - * The returned sg table is released by sg_free_table. + * Description: + * If @prv is NULL, allocate and initialize an sg table from a list of pages, + * else reuse the scatterlist passed in at @prv. + * Contiguous ranges of the pages are squashed into a single scatterlist + * entry up to the maximum size specified in @max_segment. A user may + * provide an offset at a start and a size of valid data in a buffer + * specified by the page array. * * Returns: - * 0 on success, negative error on failure + * Last SGE in sgt on success, PTR_ERR on otherwise. + * The allocation in @sgt must be released by sg_free_table. + * + * Notes: + * If this function returns non-0 (eg failure), the caller must call + * sg_free_table() to cleanup any leftover allocations. */ -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask) +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask) { - unsigned int chunks, cur_page, seg_len, i; - int ret; - struct scatterlist *s; + unsigned int chunks, cur_page, seg_len, i, prv_len = 0; + unsigned int added_nents = 0; + struct scatterlist *s = prv; if (WARN_ON(!max_segment || offset_in_page(max_segment))) - return -EINVAL; + return ERR_PTR(-EINVAL); + + if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv) + return ERR_PTR(-EOPNOTSUPP); + + if (prv) { + unsigned long paddr = (page_to_pfn(sg_page(prv)) * PAGE_SIZE + + prv->offset + prv->length) / + PAGE_SIZE; + + if (WARN_ON(offset)) + return ERR_PTR(-EINVAL); + + /* Merge contiguous pages into the last SG */ + prv_len = prv->length; + while (n_pages && page_to_pfn(pages[0]) == paddr) { + if (prv->length + PAGE_SIZE > max_segment) + break; + prv->length += PAGE_SIZE; + paddr++; + pages++; + n_pages--; + } + if (!n_pages) + goto out; + } /* compute number of contiguous chunks */ chunks = 1; @@ -410,13 +475,9 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, } } - ret = sg_alloc_table(sgt, chunks, gfp_mask); - if (unlikely(ret)) - return ret; - /* merging chunks and putting them into the scatterlist */ cur_page = 0; - for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { + for (i = 0; i < chunks; i++) { unsigned int j, chunk_size; /* look for the end of the current chunk */ @@ -429,15 +490,30 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, break; } + /* Pass how many chunks might be left */ + s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask); + if (IS_ERR(s)) { + /* + * Adjust entry length to be as before function was + * called. + */ + if (prv) + prv->length = prv_len; + return s; + } chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; sg_set_page(s, pages[cur_page], min_t(unsigned long, size, chunk_size), offset); + added_nents++; size -= chunk_size; offset = 0; cur_page = j; } - - return 0; + sgt->nents += added_nents; +out: + if (!left_pages) + sg_mark_end(s); + return s; } EXPORT_SYMBOL(__sg_alloc_table_from_pages); @@ -465,8 +541,9 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask) { - return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, - SCATTERLIST_MAX_SEGMENT, gfp_mask); + return PTR_ERR_OR_ZERO(__sg_alloc_table_from_pages(sgt, pages, n_pages, + offset, size, SCATTERLIST_MAX_SEGMENT, + NULL, 0, gfp_mask)); } EXPORT_SYMBOL(sg_alloc_table_from_pages); diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c index 0a1464181226..4899359a31ac 100644 --- a/tools/testing/scatterlist/main.c +++ b/tools/testing/scatterlist/main.c @@ -55,14 +55,13 @@ int main(void) for (i = 0, test = tests; test->expected_segments; test++, i++) { struct page *pages[MAX_PAGES]; struct sg_table st; - int ret; + struct scatterlist *sg; set_pages(pages, test->pfn, test->num_pages); - ret = __sg_alloc_table_from_pages(&st, pages, test->num_pages, - 0, test->size, test->max_seg, - GFP_KERNEL); - assert(ret == test->alloc_ret); + sg = __sg_alloc_table_from_pages(&st, pages, test->num_pages, 0, + test->size, test->max_seg, NULL, 0, GFP_KERNEL); + assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret); if (test->alloc_ret) continue; -- 2.26.2 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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 796A7C47427 for ; Sun, 4 Oct 2020 15:44:00 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 378A620759 for ; Sun, 4 Oct 2020 15:44:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="XazOb65H" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 378A620759 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6AF1489F4A; Sun, 4 Oct 2020 15:43:59 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id D534889E50; Sun, 4 Oct 2020 15:43:57 +0000 (UTC) Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0EC0B20735; Sun, 4 Oct 2020 15:43:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601826237; bh=cMP0wpbyjV/IgdoWA8GFyhNdFCLseQ+W1zGduoOqTuo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XazOb65HVrgpSmRiSceGVm2q2yryjkuepf6G/LXWO3qkAed580vQdH/mipD4PuegF E53dn5FKQvLWWTLFCuaoeH/vA5eSNH9zogmj30fOer4bumH3qf5xdDAiR32ZZUlI0n 9OV/g8m2C4KMPBK5spl4CUf85NhIQj1X+Od66oio= From: Leon Romanovsky To: Doug Ledford , Jason Gunthorpe Subject: [PATCH rdma-next v5 1/4] lib/scatterlist: Add support in dynamic allocation of SG table from pages Date: Sun, 4 Oct 2020 18:43:37 +0300 Message-Id: <20201004154340.1080481-2-leon@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201004154340.1080481-1-leon@kernel.org> References: <20201004154340.1080481-1-leon@kernel.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tvrtko Ursulin , David Airlie , intel-gfx@lists.freedesktop.org, Roland Scheidegger , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, VMware Graphics , Rodrigo Vivi , Maor Gottlieb , Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Maor Gottlieb Extend __sg_alloc_table_from_pages to support dynamic allocation of SG table from pages. It should be used by drivers that can't supply all the pages at one time. This function returns the last populated SGE in the table. Users should pass it as an argument to the function from the second call and forward. As before, nents will be equal to the number of populated SGEs (chunks). With this new extension, drivers can benefit the optimization of merging contiguous pages without a need to allocate all pages in advance and hold them in a large buffer. E.g. with the Infiniband driver that allocates a single page for hold the pages. For 1TB memory registration, the temporary buffer would consume only 4KB, instead of 2GB. Signed-off-by: Maor Gottlieb Reviewed-by: Christoph Hellwig Signed-off-by: Leon Romanovsky --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 +- drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 15 ++- include/linux/scatterlist.h | 38 +++--- lib/scatterlist.c | 125 ++++++++++++++++---- tools/testing/scatterlist/main.c | 9 +- 5 files changed, 142 insertions(+), 57 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index 12b30075134a..f2eaed6aca3d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -403,6 +403,7 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, unsigned int max_segment = i915_sg_segment_size(); struct sg_table *st; unsigned int sg_page_sizes; + struct scatterlist *sg; int ret; st = kmalloc(sizeof(*st), GFP_KERNEL); @@ -410,13 +411,12 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOMEM); alloc_table: - ret = __sg_alloc_table_from_pages(st, pvec, num_pages, - 0, num_pages << PAGE_SHIFT, - max_segment, - GFP_KERNEL); - if (ret) { + sg = __sg_alloc_table_from_pages(st, pvec, num_pages, 0, + num_pages << PAGE_SHIFT, max_segment, + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { kfree(st); - return ERR_PTR(ret); + return ERR_CAST(sg); } ret = i915_gem_gtt_prepare_pages(obj, st); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c index ab524ab3b0b4..f22acd398b1f 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c @@ -419,6 +419,7 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) int ret = 0; static size_t sgl_size; static size_t sgt_size; + struct scatterlist *sg; if (vmw_tt->mapped) return 0; @@ -441,13 +442,15 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) if (unlikely(ret != 0)) return ret; - ret = __sg_alloc_table_from_pages - (&vmw_tt->sgt, vsgt->pages, vsgt->num_pages, 0, - (unsigned long) vsgt->num_pages << PAGE_SHIFT, - dma_get_max_seg_size(dev_priv->dev->dev), - GFP_KERNEL); - if (unlikely(ret != 0)) + sg = __sg_alloc_table_from_pages(&vmw_tt->sgt, vsgt->pages, + vsgt->num_pages, 0, + (unsigned long) vsgt->num_pages << PAGE_SHIFT, + dma_get_max_seg_size(dev_priv->dev->dev), + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { + ret = PTR_ERR(sg); goto out_sg_alloc_fail; + } if (vsgt->num_pages > vmw_tt->sgt.nents) { uint64_t over_alloc = diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 45cf7b69d852..36c47e7e66a2 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -165,6 +165,22 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, #define for_each_sgtable_dma_sg(sgt, sg, i) \ for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) +static inline void __sg_chain(struct scatterlist *chain_sg, + struct scatterlist *sgl) +{ + /* + * offset and length are unused for chain entry. Clear them. + */ + chain_sg->offset = 0; + chain_sg->length = 0; + + /* + * Set lowest bit to indicate a link pointer, and make sure to clear + * the termination bit if it happens to be set. + */ + chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; +} + /** * sg_chain - Chain two sglists together * @prv: First scatterlist @@ -178,18 +194,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, struct scatterlist *sgl) { - /* - * offset and length are unused for chain entry. Clear them. - */ - prv[prv_nents - 1].offset = 0; - prv[prv_nents - 1].length = 0; - - /* - * Set lowest bit to indicate a link pointer, and make sure to clear - * the termination bit if it happens to be set. - */ - prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN) - & ~SG_END; + __sg_chain(&prv[prv_nents - 1], sgl); } /** @@ -286,10 +291,11 @@ void sg_free_table(struct sg_table *); int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask); +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask); int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 5d63a8857f36..e102fdfaa75b 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -365,6 +365,37 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) } EXPORT_SYMBOL(sg_alloc_table); +static struct scatterlist *get_next_sg(struct sg_table *table, + struct scatterlist *cur, + unsigned long needed_sges, + gfp_t gfp_mask) +{ + struct scatterlist *new_sg, *next_sg; + unsigned int alloc_size; + + if (cur) { + next_sg = sg_next(cur); + /* Check if last entry should be keeped for chainning */ + if (!sg_is_last(next_sg) || needed_sges == 1) + return next_sg; + } + + alloc_size = min_t(unsigned long, needed_sges, SG_MAX_SINGLE_ALLOC); + new_sg = sg_kmalloc(alloc_size, gfp_mask); + if (!new_sg) + return ERR_PTR(-ENOMEM); + sg_init_table(new_sg, alloc_size); + if (cur) { + __sg_chain(next_sg, new_sg); + table->orig_nents += alloc_size - 1; + } else { + table->sgl = new_sg; + table->orig_nents = alloc_size; + table->nents = 0; + } + return new_sg; +} + /** * __sg_alloc_table_from_pages - Allocate and initialize an sg table from * an array of pages @@ -374,29 +405,63 @@ EXPORT_SYMBOL(sg_alloc_table); * @offset: Offset from start of the first page to the start of a buffer * @size: Number of valid bytes in the buffer (after offset) * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) + * @prv: Last populated sge in sgt + * @left_pages: Left pages caller have to set after this call * @gfp_mask: GFP allocation mask * - * Description: - * Allocate and initialize an sg table from a list of pages. Contiguous - * ranges of the pages are squashed into a single scatterlist node up to the - * maximum size specified in @max_segment. An user may provide an offset at a - * start and a size of valid data in a buffer specified by the page array. - * The returned sg table is released by sg_free_table. + * Description: + * If @prv is NULL, allocate and initialize an sg table from a list of pages, + * else reuse the scatterlist passed in at @prv. + * Contiguous ranges of the pages are squashed into a single scatterlist + * entry up to the maximum size specified in @max_segment. A user may + * provide an offset at a start and a size of valid data in a buffer + * specified by the page array. * * Returns: - * 0 on success, negative error on failure + * Last SGE in sgt on success, PTR_ERR on otherwise. + * The allocation in @sgt must be released by sg_free_table. + * + * Notes: + * If this function returns non-0 (eg failure), the caller must call + * sg_free_table() to cleanup any leftover allocations. */ -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask) +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask) { - unsigned int chunks, cur_page, seg_len, i; - int ret; - struct scatterlist *s; + unsigned int chunks, cur_page, seg_len, i, prv_len = 0; + unsigned int added_nents = 0; + struct scatterlist *s = prv; if (WARN_ON(!max_segment || offset_in_page(max_segment))) - return -EINVAL; + return ERR_PTR(-EINVAL); + + if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv) + return ERR_PTR(-EOPNOTSUPP); + + if (prv) { + unsigned long paddr = (page_to_pfn(sg_page(prv)) * PAGE_SIZE + + prv->offset + prv->length) / + PAGE_SIZE; + + if (WARN_ON(offset)) + return ERR_PTR(-EINVAL); + + /* Merge contiguous pages into the last SG */ + prv_len = prv->length; + while (n_pages && page_to_pfn(pages[0]) == paddr) { + if (prv->length + PAGE_SIZE > max_segment) + break; + prv->length += PAGE_SIZE; + paddr++; + pages++; + n_pages--; + } + if (!n_pages) + goto out; + } /* compute number of contiguous chunks */ chunks = 1; @@ -410,13 +475,9 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, } } - ret = sg_alloc_table(sgt, chunks, gfp_mask); - if (unlikely(ret)) - return ret; - /* merging chunks and putting them into the scatterlist */ cur_page = 0; - for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { + for (i = 0; i < chunks; i++) { unsigned int j, chunk_size; /* look for the end of the current chunk */ @@ -429,15 +490,30 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, break; } + /* Pass how many chunks might be left */ + s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask); + if (IS_ERR(s)) { + /* + * Adjust entry length to be as before function was + * called. + */ + if (prv) + prv->length = prv_len; + return s; + } chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; sg_set_page(s, pages[cur_page], min_t(unsigned long, size, chunk_size), offset); + added_nents++; size -= chunk_size; offset = 0; cur_page = j; } - - return 0; + sgt->nents += added_nents; +out: + if (!left_pages) + sg_mark_end(s); + return s; } EXPORT_SYMBOL(__sg_alloc_table_from_pages); @@ -465,8 +541,9 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask) { - return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, - SCATTERLIST_MAX_SEGMENT, gfp_mask); + return PTR_ERR_OR_ZERO(__sg_alloc_table_from_pages(sgt, pages, n_pages, + offset, size, SCATTERLIST_MAX_SEGMENT, + NULL, 0, gfp_mask)); } EXPORT_SYMBOL(sg_alloc_table_from_pages); diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c index 0a1464181226..4899359a31ac 100644 --- a/tools/testing/scatterlist/main.c +++ b/tools/testing/scatterlist/main.c @@ -55,14 +55,13 @@ int main(void) for (i = 0, test = tests; test->expected_segments; test++, i++) { struct page *pages[MAX_PAGES]; struct sg_table st; - int ret; + struct scatterlist *sg; set_pages(pages, test->pfn, test->num_pages); - ret = __sg_alloc_table_from_pages(&st, pages, test->num_pages, - 0, test->size, test->max_seg, - GFP_KERNEL); - assert(ret == test->alloc_ret); + sg = __sg_alloc_table_from_pages(&st, pages, test->num_pages, 0, + test->size, test->max_seg, NULL, 0, GFP_KERNEL); + assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret); if (test->alloc_ret) continue; -- 2.26.2 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel 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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 A09BBC47426 for ; 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Sun, 4 Oct 2020 15:43:57 +0000 (UTC) Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0EC0B20735; Sun, 4 Oct 2020 15:43:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601826237; bh=cMP0wpbyjV/IgdoWA8GFyhNdFCLseQ+W1zGduoOqTuo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XazOb65HVrgpSmRiSceGVm2q2yryjkuepf6G/LXWO3qkAed580vQdH/mipD4PuegF E53dn5FKQvLWWTLFCuaoeH/vA5eSNH9zogmj30fOer4bumH3qf5xdDAiR32ZZUlI0n 9OV/g8m2C4KMPBK5spl4CUf85NhIQj1X+Od66oio= From: Leon Romanovsky To: Doug Ledford , Jason Gunthorpe Date: Sun, 4 Oct 2020 18:43:37 +0300 Message-Id: <20201004154340.1080481-2-leon@kernel.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201004154340.1080481-1-leon@kernel.org> References: <20201004154340.1080481-1-leon@kernel.org> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH rdma-next v5 1/4] lib/scatterlist: Add support in dynamic allocation of SG table from pages X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , intel-gfx@lists.freedesktop.org, Roland Scheidegger , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, VMware Graphics , Maor Gottlieb , Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Maor Gottlieb Extend __sg_alloc_table_from_pages to support dynamic allocation of SG table from pages. It should be used by drivers that can't supply all the pages at one time. This function returns the last populated SGE in the table. Users should pass it as an argument to the function from the second call and forward. As before, nents will be equal to the number of populated SGEs (chunks). With this new extension, drivers can benefit the optimization of merging contiguous pages without a need to allocate all pages in advance and hold them in a large buffer. E.g. with the Infiniband driver that allocates a single page for hold the pages. For 1TB memory registration, the temporary buffer would consume only 4KB, instead of 2GB. Signed-off-by: Maor Gottlieb Reviewed-by: Christoph Hellwig Signed-off-by: Leon Romanovsky --- drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 12 +- drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c | 15 ++- include/linux/scatterlist.h | 38 +++--- lib/scatterlist.c | 125 ++++++++++++++++---- tools/testing/scatterlist/main.c | 9 +- 5 files changed, 142 insertions(+), 57 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c index 12b30075134a..f2eaed6aca3d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c @@ -403,6 +403,7 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, unsigned int max_segment = i915_sg_segment_size(); struct sg_table *st; unsigned int sg_page_sizes; + struct scatterlist *sg; int ret; st = kmalloc(sizeof(*st), GFP_KERNEL); @@ -410,13 +411,12 @@ __i915_gem_userptr_alloc_pages(struct drm_i915_gem_object *obj, return ERR_PTR(-ENOMEM); alloc_table: - ret = __sg_alloc_table_from_pages(st, pvec, num_pages, - 0, num_pages << PAGE_SHIFT, - max_segment, - GFP_KERNEL); - if (ret) { + sg = __sg_alloc_table_from_pages(st, pvec, num_pages, 0, + num_pages << PAGE_SHIFT, max_segment, + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { kfree(st); - return ERR_PTR(ret); + return ERR_CAST(sg); } ret = i915_gem_gtt_prepare_pages(obj, st); diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c index ab524ab3b0b4..f22acd398b1f 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c @@ -419,6 +419,7 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) int ret = 0; static size_t sgl_size; static size_t sgt_size; + struct scatterlist *sg; if (vmw_tt->mapped) return 0; @@ -441,13 +442,15 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt) if (unlikely(ret != 0)) return ret; - ret = __sg_alloc_table_from_pages - (&vmw_tt->sgt, vsgt->pages, vsgt->num_pages, 0, - (unsigned long) vsgt->num_pages << PAGE_SHIFT, - dma_get_max_seg_size(dev_priv->dev->dev), - GFP_KERNEL); - if (unlikely(ret != 0)) + sg = __sg_alloc_table_from_pages(&vmw_tt->sgt, vsgt->pages, + vsgt->num_pages, 0, + (unsigned long) vsgt->num_pages << PAGE_SHIFT, + dma_get_max_seg_size(dev_priv->dev->dev), + NULL, 0, GFP_KERNEL); + if (IS_ERR(sg)) { + ret = PTR_ERR(sg); goto out_sg_alloc_fail; + } if (vsgt->num_pages > vmw_tt->sgt.nents) { uint64_t over_alloc = diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 45cf7b69d852..36c47e7e66a2 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -165,6 +165,22 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, #define for_each_sgtable_dma_sg(sgt, sg, i) \ for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) +static inline void __sg_chain(struct scatterlist *chain_sg, + struct scatterlist *sgl) +{ + /* + * offset and length are unused for chain entry. Clear them. + */ + chain_sg->offset = 0; + chain_sg->length = 0; + + /* + * Set lowest bit to indicate a link pointer, and make sure to clear + * the termination bit if it happens to be set. + */ + chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; +} + /** * sg_chain - Chain two sglists together * @prv: First scatterlist @@ -178,18 +194,7 @@ static inline void sg_set_buf(struct scatterlist *sg, const void *buf, static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, struct scatterlist *sgl) { - /* - * offset and length are unused for chain entry. Clear them. - */ - prv[prv_nents - 1].offset = 0; - prv[prv_nents - 1].length = 0; - - /* - * Set lowest bit to indicate a link pointer, and make sure to clear - * the termination bit if it happens to be set. - */ - prv[prv_nents - 1].page_link = ((unsigned long) sgl | SG_CHAIN) - & ~SG_END; + __sg_chain(&prv[prv_nents - 1], sgl); } /** @@ -286,10 +291,11 @@ void sg_free_table(struct sg_table *); int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask); +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask); int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask); diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 5d63a8857f36..e102fdfaa75b 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -365,6 +365,37 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) } EXPORT_SYMBOL(sg_alloc_table); +static struct scatterlist *get_next_sg(struct sg_table *table, + struct scatterlist *cur, + unsigned long needed_sges, + gfp_t gfp_mask) +{ + struct scatterlist *new_sg, *next_sg; + unsigned int alloc_size; + + if (cur) { + next_sg = sg_next(cur); + /* Check if last entry should be keeped for chainning */ + if (!sg_is_last(next_sg) || needed_sges == 1) + return next_sg; + } + + alloc_size = min_t(unsigned long, needed_sges, SG_MAX_SINGLE_ALLOC); + new_sg = sg_kmalloc(alloc_size, gfp_mask); + if (!new_sg) + return ERR_PTR(-ENOMEM); + sg_init_table(new_sg, alloc_size); + if (cur) { + __sg_chain(next_sg, new_sg); + table->orig_nents += alloc_size - 1; + } else { + table->sgl = new_sg; + table->orig_nents = alloc_size; + table->nents = 0; + } + return new_sg; +} + /** * __sg_alloc_table_from_pages - Allocate and initialize an sg table from * an array of pages @@ -374,29 +405,63 @@ EXPORT_SYMBOL(sg_alloc_table); * @offset: Offset from start of the first page to the start of a buffer * @size: Number of valid bytes in the buffer (after offset) * @max_segment: Maximum size of a scatterlist node in bytes (page aligned) + * @prv: Last populated sge in sgt + * @left_pages: Left pages caller have to set after this call * @gfp_mask: GFP allocation mask * - * Description: - * Allocate and initialize an sg table from a list of pages. Contiguous - * ranges of the pages are squashed into a single scatterlist node up to the - * maximum size specified in @max_segment. An user may provide an offset at a - * start and a size of valid data in a buffer specified by the page array. - * The returned sg table is released by sg_free_table. + * Description: + * If @prv is NULL, allocate and initialize an sg table from a list of pages, + * else reuse the scatterlist passed in at @prv. + * Contiguous ranges of the pages are squashed into a single scatterlist + * entry up to the maximum size specified in @max_segment. A user may + * provide an offset at a start and a size of valid data in a buffer + * specified by the page array. * * Returns: - * 0 on success, negative error on failure + * Last SGE in sgt on success, PTR_ERR on otherwise. + * The allocation in @sgt must be released by sg_free_table. + * + * Notes: + * If this function returns non-0 (eg failure), the caller must call + * sg_free_table() to cleanup any leftover allocations. */ -int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, - unsigned int n_pages, unsigned int offset, - unsigned long size, unsigned int max_segment, - gfp_t gfp_mask) +struct scatterlist *__sg_alloc_table_from_pages(struct sg_table *sgt, + struct page **pages, unsigned int n_pages, unsigned int offset, + unsigned long size, unsigned int max_segment, + struct scatterlist *prv, unsigned int left_pages, + gfp_t gfp_mask) { - unsigned int chunks, cur_page, seg_len, i; - int ret; - struct scatterlist *s; + unsigned int chunks, cur_page, seg_len, i, prv_len = 0; + unsigned int added_nents = 0; + struct scatterlist *s = prv; if (WARN_ON(!max_segment || offset_in_page(max_segment))) - return -EINVAL; + return ERR_PTR(-EINVAL); + + if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv) + return ERR_PTR(-EOPNOTSUPP); + + if (prv) { + unsigned long paddr = (page_to_pfn(sg_page(prv)) * PAGE_SIZE + + prv->offset + prv->length) / + PAGE_SIZE; + + if (WARN_ON(offset)) + return ERR_PTR(-EINVAL); + + /* Merge contiguous pages into the last SG */ + prv_len = prv->length; + while (n_pages && page_to_pfn(pages[0]) == paddr) { + if (prv->length + PAGE_SIZE > max_segment) + break; + prv->length += PAGE_SIZE; + paddr++; + pages++; + n_pages--; + } + if (!n_pages) + goto out; + } /* compute number of contiguous chunks */ chunks = 1; @@ -410,13 +475,9 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, } } - ret = sg_alloc_table(sgt, chunks, gfp_mask); - if (unlikely(ret)) - return ret; - /* merging chunks and putting them into the scatterlist */ cur_page = 0; - for_each_sg(sgt->sgl, s, sgt->orig_nents, i) { + for (i = 0; i < chunks; i++) { unsigned int j, chunk_size; /* look for the end of the current chunk */ @@ -429,15 +490,30 @@ int __sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, break; } + /* Pass how many chunks might be left */ + s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask); + if (IS_ERR(s)) { + /* + * Adjust entry length to be as before function was + * called. + */ + if (prv) + prv->length = prv_len; + return s; + } chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset; sg_set_page(s, pages[cur_page], min_t(unsigned long, size, chunk_size), offset); + added_nents++; size -= chunk_size; offset = 0; cur_page = j; } - - return 0; + sgt->nents += added_nents; +out: + if (!left_pages) + sg_mark_end(s); + return s; } EXPORT_SYMBOL(__sg_alloc_table_from_pages); @@ -465,8 +541,9 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, struct page **pages, unsigned int n_pages, unsigned int offset, unsigned long size, gfp_t gfp_mask) { - return __sg_alloc_table_from_pages(sgt, pages, n_pages, offset, size, - SCATTERLIST_MAX_SEGMENT, gfp_mask); + return PTR_ERR_OR_ZERO(__sg_alloc_table_from_pages(sgt, pages, n_pages, + offset, size, SCATTERLIST_MAX_SEGMENT, + NULL, 0, gfp_mask)); } EXPORT_SYMBOL(sg_alloc_table_from_pages); diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c index 0a1464181226..4899359a31ac 100644 --- a/tools/testing/scatterlist/main.c +++ b/tools/testing/scatterlist/main.c @@ -55,14 +55,13 @@ int main(void) for (i = 0, test = tests; test->expected_segments; test++, i++) { struct page *pages[MAX_PAGES]; struct sg_table st; - int ret; + struct scatterlist *sg; set_pages(pages, test->pfn, test->num_pages); - ret = __sg_alloc_table_from_pages(&st, pages, test->num_pages, - 0, test->size, test->max_seg, - GFP_KERNEL); - assert(ret == test->alloc_ret); + sg = __sg_alloc_table_from_pages(&st, pages, test->num_pages, 0, + test->size, test->max_seg, NULL, 0, GFP_KERNEL); + assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret); if (test->alloc_ret) continue; -- 2.26.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx