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[2607:f8b0:400e:c00::241]) by gmr-mx.google.com with ESMTPS id r78si32360pfb.3.2017.09.15.00.25.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Sep 2017 00:25:05 -0700 (PDT) Received-SPF: pass (google.com: domain of hamohammed.sa@gmail.com designates 2607:f8b0:400e:c00::241 as permitted sender) client-ip=2607:f8b0:400e:c00::241; Authentication-Results: gmr-mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=htTuo783; spf=pass (google.com: domain of hamohammed.sa@gmail.com designates 2607:f8b0:400e:c00::241 as permitted sender) smtp.mailfrom=hamohammed.sa@gmail.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=gmail.com Received: by mail-pf0-x241.google.com with SMTP id h4so869465pfk.0 for ; Fri, 15 Sep 2017 00:25:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=7D5uXx1Pc3vsLUJRZzjGNYhQivcFhWehn2CddkDCYDI=; b=htTuo783jlcX10W2gOeNYidj1vJkpemAqh+H+yjvRZ6RZzFrRqJ+93E23ARdhtcKaP BTOzyg6gGD5Erd0JLD9Py1wdvopmW9fvVEYlAAcM7LXM9+wzm5kKNkrawZ0UcjLOR32i sCaEQp6xHIif9v+6Rel47rXynwy6nMER7yWTtwtLYryuCULET9TkUILla2Fmm94OJwE6 Ql7oMbbCHox40oJ5pnHuPOqNXsBNryfrdeZlPTe+ksgDC7+mgizvvFJB32R63oWAZN2Z s2jowUFvYpabePv7FE3rva6BC/6LMEJr22OBUaCoNvnspn0BdOjEv96n3so7iK8UMscn z8EA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=7D5uXx1Pc3vsLUJRZzjGNYhQivcFhWehn2CddkDCYDI=; b=mWgdr4KIoodhYeSoGAZrRV0Dh+en8QJA6wZds8bYe/+7hQGPP7WERtKdK1Ky7KJTEZ QRemTbt3aL53zadKxPKziJacbn84I5W5AJ61npBfwdkMtl9tZ2PPnpyh6N6ONPFJZihL O8H04sbOB5ft2B+UPPt3R1aHn2b8SftJfMw4NJqyHEpDKVselXEidV8RNMqao5rsG/ui 88nfFNX4dE8fCo/K6MJlSA6TzVTWGHZ/xJ0QV+8wGgrIke7EoE2Pp0KkRbA1Zg9bpgXB RXI5NTZ8PUPkMqiynh26v12a+YSpnK2U1fTulcKyt2U6my0XL5ow6ioRsYgup4ND4dcE RmOw== X-Gm-Message-State: AHPjjUiOpOkHdIo80cCztiwA4F79VpFhkG+HPVM56Yi0RJvqu07HykTa X7Jadjl/Dm5sLOgh2dY= X-Google-Smtp-Source: AOwi7QCeb6v5MyY1yYW+nOtpWOHrlq5XwQMIqv3jMiVVtMKrbEyOTRWpD2fCqra7qHW6Q2FaiESfig== X-Received: by 10.99.164.18 with SMTP id c18mr8557655pgf.359.1505460305354; Fri, 15 Sep 2017 00:25:05 -0700 (PDT) Return-Path: Received: from Haneen ([64.77.242.50]) by smtp.gmail.com with ESMTPSA id h82sm1025694pfd.148.2017.09.15.00.25.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Sep 2017 00:25:04 -0700 (PDT) Date: Fri, 15 Sep 2017 01:25:02 -0600 From: Haneen Mohammed To: Julia Lawall Cc: outreachy-kernel Subject: About handling dma_mapping_error result after dma_map_* Message-ID: <20170915072502.GA11238@Haneen> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) Hello, I have a question about handling dma_mapping_error result. Is it enough to add a warning after it? Because I have found two missing dma_mapping_error in the drm/via driver but I wasn't sure how to handle the return value if an error was found. Below is the code mentioned: --- drivers/gpu/drm/via/via_dmablit.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c index 98aae98..5c11756 100644 --- a/drivers/gpu/drm/via/via_dmablit.c +++ b/drivers/gpu/drm/via/via_dmablit.c @@ -132,12 +132,19 @@ via_map_blit_for_device(struct pci_dev *pdev, VIA_PFN(first_addr)], VIA_PGOFF(cur_mem), remaining_len, vsg->direction); + if (dma_mapping_error(&pdev->dev, + desc_ptr->mem_addr)) + dev_warn(&pdev->dev, "DMA mapping failed\n"); + desc_ptr->dev_addr = cur_fb; desc_ptr->size = remaining_len; desc_ptr->next = (uint32_t) next; next = dma_map_single(&pdev->dev, desc_ptr, sizeof(*desc_ptr), DMA_TO_DEVICE); + if (dma_mapping_error(&pdev->dev, + next)) + dev_warn(&pdev->dev, "DMA mapping failed\n"); desc_ptr++; if (++num_descriptors_this_page >= vsg->descriptors_per_page) { num_descriptors_this_page = 0; -- 2.7.4 Thank you! Haneen