Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754237Ab3E0QNj (ORCPT ); Mon, 27 May 2013 12:13:39 -0400 Received: from mail-pa0-f53.google.com ([209.85.220.53]:50875 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753072Ab3E0QNg (ORCPT ); Mon, 27 May 2013 12:13:36 -0400 From: Ming Lei To: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Ming Lei , Shuah Khan , Joerg Roedel , Andrew Morton , Alexander Duyck , Konrad Rzeszutek Wilk Subject: [RFC PATCH 1/2] dma-debug: allow size to become smaller in dma_unmap Date: Tue, 28 May 2013 00:13:06 +0800 Message-Id: <1369671187-24430-2-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1369671187-24430-1-git-send-email-ming.lei@canonical.com> References: <1369671187-24430-1-git-send-email-ming.lei@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3614 Lines: 95 This patch looses the check on DMA buffer size for streaming DMA unmap, based on the below fact: - it is common to see only part of DMA transfer is completed, especially in case of DMA_FROM_DEVICE So it isn't necessary to unmap the whole DMA buffer inside DMA unmapping, and unmapping the actual completed buffer should be more efficient. Considered that unmapping is often called in hard irq context, time of irq handling can be saved. Cc: Shuah Khan Cc: Joerg Roedel Cc: Andrew Morton Cc: Alexander Duyck Cc: Konrad Rzeszutek Wilk Signed-off-by: Ming Lei --- lib/dma-debug.c | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) diff --git a/lib/dma-debug.c b/lib/dma-debug.c index d87a17a..202c522 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -857,6 +857,7 @@ static void check_unmap(struct dma_debug_entry *ref) struct dma_debug_entry *entry; struct hash_bucket *bucket; unsigned long flags; + unsigned int size_invalid = 0; bucket = get_hash_bucket(ref, &flags); entry = bucket_find_exact(bucket, ref); @@ -879,13 +880,8 @@ static void check_unmap(struct dma_debug_entry *ref) return; } - if (ref->size != entry->size) { - err_printk(ref->dev, entry, "DMA-API: device driver frees " - "DMA memory with different size " - "[device address=0x%016llx] [map size=%llu bytes] " - "[unmap size=%llu bytes]\n", - ref->dev_addr, entry->size, ref->size); - } + if (ref->size > entry->size) + size_invalid = 1; if (ref->type != entry->type) { err_printk(ref->dev, entry, "DMA-API: device driver frees " @@ -894,18 +890,27 @@ static void check_unmap(struct dma_debug_entry *ref) "[mapped as %s] [unmapped as %s]\n", ref->dev_addr, ref->size, type2name[entry->type], type2name[ref->type]); - } else if ((entry->type == dma_debug_coherent) && - (ref->paddr != entry->paddr)) { - err_printk(ref->dev, entry, "DMA-API: device driver frees " - "DMA memory with different CPU address " - "[device address=0x%016llx] [size=%llu bytes] " - "[cpu alloc address=0x%016llx] " - "[cpu free address=0x%016llx]", - ref->dev_addr, ref->size, - (unsigned long long)entry->paddr, - (unsigned long long)ref->paddr); + } else if (entry->type == dma_debug_coherent) { + if (ref->paddr != entry->paddr) + err_printk(ref->dev, entry, "DMA-API: device driver frees " + "DMA memory with different CPU address " + "[device address=0x%016llx] [size=%llu bytes] " + "[cpu alloc address=0x%016llx] " + "[cpu free address=0x%016llx]", + ref->dev_addr, ref->size, + (unsigned long long)entry->paddr, + (unsigned long long)ref->paddr); + if (ref->size != entry->size) + size_invalid = 1; } + if (size_invalid) + err_printk(ref->dev, entry, "DMA-API: device driver frees " + "DMA memory with different size " + "[device address=0x%016llx] [map size=%llu bytes] " + "[unmap size=%llu bytes]\n", + ref->dev_addr, entry->size, ref->size); + if (ref->sg_call_ents && ref->type == dma_debug_sg && ref->sg_call_ents != entry->sg_call_ents) { err_printk(ref->dev, entry, "DMA-API: device driver frees " -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/