From patchwork Wed Nov 20 10:34:55 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yunsheng Lin X-Patchwork-Id: 13881010 X-Patchwork-Delegate: kuba@kernel.org Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (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 484C819D060; Wed, 20 Nov 2024 10:41:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732099305; cv=none; b=Z38+ApbL/XeJbILBkP85+3mGW6AYHEFRqeTQvNSqa1ra/1iF1cOWM5T/o6ugIJmXwscyuq7qNnUITy3oDBOXbO/d57kHxft9aosH+OdPvfA/4645m4dT8jjKWvtc0ykNHUej/L+TE5y2Az6Gy1zKcJ6PnRTxLNjJTs0Z6oEJ/7c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732099305; c=relaxed/simple; bh=mcby2DGppHd18uHygt54sfA41+/bgOa1b8xhVO49ZeU=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=NX1ISy/f8mtJ32h9fbNk85Av6Gm0wgQbNK4IWyMIkvyDSnSVCtJK4WucqyNlXSjS37u2o7wyikTu/t6/EPvV92ktARYtb5dGfJrVuM4kMxj+ZdYS6HweSMdEB022kt22vKEIK2Y1pcNPiIHCis/VMPvro1ZZCWpH6u6EoRxEOkk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4XtdBs1qkjz1V4dw; Wed, 20 Nov 2024 18:39:01 +0800 (CST) Received: from dggpemf200006.china.huawei.com (unknown [7.185.36.61]) by mail.maildlp.com (Postfix) with ESMTPS id 819D01800F2; Wed, 20 Nov 2024 18:41:39 +0800 (CST) Received: from localhost.localdomain (10.90.30.45) by dggpemf200006.china.huawei.com (7.185.36.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 20 Nov 2024 18:41:39 +0800 From: Yunsheng Lin To: , , CC: , , , Yunsheng Lin , Robin Murphy , Alexander Duyck , Andrew Morton , IOMMU , MM , Jesper Dangaard Brouer , Ilias Apalodimas , Eric Dumazet , Simon Horman , , Subject: [PATCH RFC v4 3/3] page_pool: skip dma sync operation for inflight pages Date: Wed, 20 Nov 2024 18:34:55 +0800 Message-ID: <20241120103456.396577-4-linyunsheng@huawei.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20241120103456.396577-1-linyunsheng@huawei.com> References: <20241120103456.396577-1-linyunsheng@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemf200006.china.huawei.com (7.185.36.61) X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC Skip dma sync operation for inflight pages before the page_pool_destroy() returns to the driver as DMA API expects to be called with a valid device bound to a driver as mentioned in [1]. After page_pool_destroy() is called, the page is not expected to be recycled back to pool->alloc cache and dma sync operation is not needed when the page is not recyclable or pool->ring is full, so only skip the dma sync operation for the infilght pages by clearing the pool->dma_sync under protection of rcu lock when page is recycled to pool->ring to ensure that there is no dma sync operation called after page_pool_destroy() is returned. 1. https://lore.kernel.org/all/caf31b5e-0e8f-4844-b7ba-ef59ed13b74e@arm.com/ CC: Robin Murphy CC: Alexander Duyck CC: Andrew Morton CC: IOMMU CC: MM Fixes: f71fec47c2df ("page_pool: make sure struct device is stable") Signed-off-by: Yunsheng Lin --- net/core/page_pool.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 33a314abbba4..0bde7c6c781a 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -712,7 +712,8 @@ static void page_pool_return_page(struct page_pool *pool, netmem_ref netmem) rcu_read_unlock(); } -static bool page_pool_recycle_in_ring(struct page_pool *pool, netmem_ref netmem) +static bool page_pool_recycle_in_ring(struct page_pool *pool, netmem_ref netmem, + unsigned int dma_sync_size) { int ret; /* BH protection not needed if current is softirq */ @@ -723,10 +724,13 @@ static bool page_pool_recycle_in_ring(struct page_pool *pool, netmem_ref netmem) if (!ret) { recycle_stat_inc(pool, ring); - return true; + + rcu_read_lock(); + page_pool_dma_sync_for_device(pool, netmem, dma_sync_size); + rcu_read_unlock(); } - return false; + return !ret; } /* Only allow direct recycling in special circumstances, into the @@ -779,10 +783,11 @@ __page_pool_put_page(struct page_pool *pool, netmem_ref netmem, if (likely(__page_pool_page_can_be_recycled(netmem))) { /* Read barrier done in page_ref_count / READ_ONCE */ - page_pool_dma_sync_for_device(pool, netmem, dma_sync_size); - - if (allow_direct && page_pool_recycle_in_cache(netmem, pool)) + if (allow_direct && page_pool_recycle_in_cache(netmem, pool)) { + page_pool_dma_sync_for_device(pool, netmem, + dma_sync_size); return 0; + } /* Page found as candidate for recycling */ return netmem; @@ -845,7 +850,7 @@ void page_pool_put_unrefed_netmem(struct page_pool *pool, netmem_ref netmem, netmem = __page_pool_put_page(pool, netmem, dma_sync_size, allow_direct); - if (netmem && !page_pool_recycle_in_ring(pool, netmem)) { + if (netmem && !page_pool_recycle_in_ring(pool, netmem, dma_sync_size)) { /* Cache full, fallback to free pages */ recycle_stat_inc(pool, ring_full); page_pool_return_page(pool, netmem); @@ -903,14 +908,18 @@ void page_pool_put_page_bulk(struct page_pool *pool, void **data, /* Bulk producer into ptr_ring page_pool cache */ in_softirq = page_pool_producer_lock(pool); + rcu_read_lock(); for (i = 0; i < bulk_len; i++) { if (__ptr_ring_produce(&pool->ring, data[i])) { /* ring full */ recycle_stat_inc(pool, ring_full); break; } + page_pool_dma_sync_for_device(pool, (__force netmem_ref)data[i], + -1); } recycle_stat_add(pool, ring, i); + rcu_read_unlock(); page_pool_producer_unlock(pool, in_softirq); /* Hopefully all pages was return into ptr_ring */ @@ -1200,6 +1209,8 @@ void page_pool_destroy(struct page_pool *pool) if (!page_pool_release(pool)) return; + pool->dma_sync = false; + /* Paired with rcu lock in page_pool_napi_local() to enable clearing * of pool->p.napi in page_pool_disable_direct_recycling() is seen * before returning to driver to free the napi instance.