search for: virtqueue_add_sg_singl

The virtqueue_add_buf function has two limitations: 1) it requires the caller to provide all the buffers in a single call; 2) it does not support chained scatterlists: the buffers must be provided as an array of struct scatterlist. Because of these limitations, virtio-scsi has to copy each request into a scatterlist internal to the driver. It cannot just use the one that was prepared by the

The virtqueue_add_buf function has two limitations: 1) it requires the caller to provide all the buffers in a single call; 2) it does not support chained scatterlists: the buffers must be provided as an array of struct scatterlist. Because of these limitations, virtio-scsi has to copy each request into a scatterlist internal to the driver. It cannot just use the one that was prepared by the

...next usage of the scatterlist. Other drivers are safe already, but many can be converted to the "fast-path" function virtqueue_add_buf_single suggested by mst; this is done in patch 8. Compared to the RFC, I have moved the state of virtqueue_add_sg into struct vring_desc, and I replaced virtqueue_add_sg_single with virtqueue_add_buf_single. I renamed the "count" and "count_sg" to "nents" and "nsg" following a suggestion of Stefan Hajnoczi. And of course the patch is now well tested (including virtio-serial, all three virtio-net receive paths, and virtio-blk SG_IO...

...next usage of the scatterlist. Other drivers are safe already, but many can be converted to the "fast-path" function virtqueue_add_buf_single suggested by mst; this is done in patch 8. Compared to the RFC, I have moved the state of virtqueue_add_sg into struct vring_desc, and I replaced virtqueue_add_sg_single with virtqueue_add_buf_single. I renamed the "count" and "count_sg" to "nents" and "nsg" following a suggestion of Stefan Hajnoczi. And of course the patch is now well tested (including virtio-serial, all three virtio-net receive paths, and virtio-blk SG_IO...