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*参照元 [#q68a9020] #backlinks *説明 [#d47f93d8] -パス: [[linux-4.4.1/drivers/media/v4l2-core/videobuf2-dma-contig.c]] -FIXME: これは何？ --説明 **引数 [#qf5022a2] -struct dma_buf *dbuf -- --[[linux-4.4.1/dma_buf]] -struct device *dev -- --[[linux-4.4.1/device]] -struct dma_buf_attachment *dbuf_attach -- --[[linux-4.4.1/dma_buf_attachment]] **返り値 [#tbc50df8] -int -- **参考 [#j4c7e519] *実装 [#w3d8541e] static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev, struct dma_buf_attachment *dbuf_attach) { struct vb2_dc_attachment *attach; unsigned int i; struct scatterlist *rd, *wr; struct sg_table *sgt; struct vb2_dc_buf *buf = dbuf->priv; int ret; - --[[linux-4.4.1/vb2_dc_attachment]] --[[linux-4.4.1/scatterlist]] --[[linux-4.4.1/sg_table]] --[[linux-4.4.1/vb2_dc_buf]] attach = kzalloc(sizeof(*attach), GFP_KERNEL); if (!attach) return -ENOMEM; - --[[linux-4.4.1/kzalloc()]] sgt = &attach->sgt; /* Copy the buf->base_sgt scatter list to the attachment, as we can't * map the same scatter list to multiple attachments at the same time. */ ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL); if (ret) { kfree(attach); return -ENOMEM; } - --buf->sgt_base は struct sg_table 型 --buf->sgt_base->orig_nents は unsigned long 型 --[[linux-4.4.1/sg_table]] --[[linux-4.4.1/sg_alloc_table()]] --[[linux-4.4.1/kfree()]] rd = buf->sgt_base->sgl; wr = sgt->sgl; for (i = 0; i < sgt->orig_nents; ++i) { sg_set_page(wr, sg_page(rd), rd->length, rd->offset); rd = sg_next(rd); wr = sg_next(wr); } - --buf->sgt_base->sgl は struct scatterlist * 型 --[[linux-4.4.1/scatterlist]] --[[linux-4.4.1/sg_set_page()]] --[[linux-4.4.1/sg_page()]] --[[linux-4.4.1/sg_next()]] attach->dma_dir = DMA_NONE; dbuf_attach->priv = attach; return 0; } *コメント [#zfaa0091]
