From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 3/3] libata: make ata_sg_setup_one() trim zero length sg Date: Mon, 20 Feb 2006 23:48:38 +0900 Message-ID: <11404469181022-git-send-email-htejun@gmail.com> References: <43F9970F.9010903@pobox.com> Reply-To: Tejun Heo Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Return-path: Received: from pproxy.gmail.com ([64.233.166.179]:50315 "EHLO pproxy.gmail.com") by vger.kernel.org with ESMTP id S1030262AbWBTOsj (ORCPT ); Mon, 20 Feb 2006 09:48:39 -0500 Received: by pproxy.gmail.com with SMTP id w49so1120834pyg for ; Mon, 20 Feb 2006 06:48:39 -0800 (PST) In-Reply-To: <43F9970F.9010903@pobox.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: jgarzik@pobox.com, linux-ide@vger.kernel.org Cc: Tejun Heo This patch makes ata_sg_setup_one() trim sg entry (thus making qc->n_elem zero) if padding results in zero length sg entry. Signed-off-by: Tejun Heo --- drivers/scsi/libata-core.c | 13 ++++++++----- 1 files changed, 8 insertions(+), 5 deletions(-) 600e098c7092d0c0ba4c316e2cec2d1c8edc495c diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index bbac87a..5f1d758 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -2514,7 +2514,7 @@ static void ata_sg_clean(struct ata_queu assert(sg != NULL); if (qc->flags & ATA_QCFLAG_SINGLE) - assert(qc->n_elem == 1); + assert(qc->n_elem <= 1); VPRINTK("unmapping %u sg elements\n", qc->n_elem); @@ -2537,7 +2537,7 @@ static void ata_sg_clean(struct ata_queu kunmap_atomic(addr, KM_IRQ0); } } else { - if (sg_dma_len(&sg[0]) > 0) + if (qc->n_elem) dma_unmap_single(ap->host_set->dev, sg_dma_address(&sg[0]), sg_dma_len(&sg[0]), dir); @@ -2715,6 +2715,7 @@ static int ata_sg_setup_one(struct ata_q int dir = qc->dma_dir; struct scatterlist *sg = qc->__sg; dma_addr_t dma_address; + int trim_sg = 0; /* we must lengthen transfers to end on a 32-bit boundary */ qc->pad_len = sg->length & 3; @@ -2734,13 +2735,15 @@ static int ata_sg_setup_one(struct ata_q sg_dma_len(psg) = ATA_DMA_PAD_SZ; /* trim sg */ sg->length -= qc->pad_len; + if (sg->length == 0) + trim_sg = 1; DPRINTK("padding done, sg->length=%u pad_len=%u\n", sg->length, qc->pad_len); } - if (!sg->length) { - sg_dma_address(sg) = 0; + if (trim_sg) { + qc->n_elem--; goto skip_map; } @@ -2753,9 +2756,9 @@ static int ata_sg_setup_one(struct ata_q } sg_dma_address(sg) = dma_address; -skip_map: sg_dma_len(sg) = sg->length; +skip_map: DPRINTK("mapped buffer of %d bytes for %s\n", sg_dma_len(sg), qc->tf.flags & ATA_TFLAG_WRITE ? "write" : "read"); -- 1.1.5