From aaa789843a93faa7e2bb309b7647f1cc0a083158 Mon Sep 17 00:00:00 2001 From: Xuan Zhuo Date: Tue, 12 Nov 2024 09:29:18 +0800 Subject: [PATCH] virtio_ring: packed: record extras for indirect buffers The subsequent commit needs to know whether every indirect buffer is premapped or not. So we need to introduce an extra struct for every indirect buffer to record this info. Signed-off-by: Xuan Zhuo Acked-by: Jason Wang Link: https://patch.msgid.link/20241112012928.102478-4-xuanzhuo@linux.alibaba.com Signed-off-by: Jakub Kicinski --- drivers/virtio/virtio_ring.c | 60 +++++++++++++++++++++--------------- 1 file changed, 36 insertions(+), 24 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 405d5a3487952..cfe70c40f6306 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -78,7 +78,11 @@ struct vring_desc_state_split { struct vring_desc_state_packed { void *data; /* Data for callback. */ - struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */ + + /* Indirect desc table and extra table, if any. These two will be + * allocated together. So we won't stress more to the memory allocator. + */ + struct vring_packed_desc *indir_desc; u16 num; /* Descriptor list length. */ u16 last; /* The last desc state in a list. */ }; @@ -1238,27 +1242,12 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq, } } -static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, - const struct vring_packed_desc *desc) -{ - u16 flags; - - if (!vring_need_unmap_buffer(vq)) - return; - - flags = le16_to_cpu(desc->flags); - - dma_unmap_page(vring_dma_dev(vq), - le64_to_cpu(desc->addr), - le32_to_cpu(desc->len), - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); -} - static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg, gfp_t gfp) { + struct vring_desc_extra *extra; struct vring_packed_desc *desc; + int i, size; /* * We require lowmem mappings for the descriptors because @@ -1267,7 +1256,16 @@ static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg, */ gfp &= ~__GFP_HIGHMEM; - desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp); + size = (sizeof(*desc) + sizeof(*extra)) * total_sg; + + desc = kmalloc(size, gfp); + if (!desc) + return NULL; + + extra = (struct vring_desc_extra *)&desc[total_sg]; + + for (i = 0; i < total_sg; i++) + extra[i].next = i + 1; return desc; } @@ -1280,6 +1278,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, void *data, gfp_t gfp) { + struct vring_desc_extra *extra; struct vring_packed_desc *desc; struct scatterlist *sg; unsigned int i, n, err_idx; @@ -1291,6 +1290,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, if (!desc) return -ENOMEM; + extra = (struct vring_desc_extra *)&desc[total_sg]; + if (unlikely(vq->vq.num_free < 1)) { pr_debug("Can't add buf len 1 - avail = 0\n"); kfree(desc); @@ -1312,6 +1313,13 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, 0 : VRING_DESC_F_WRITE); desc[i].addr = cpu_to_le64(addr); desc[i].len = cpu_to_le32(sg->length); + + if (unlikely(vq->use_dma_api)) { + extra[i].addr = addr; + extra[i].len = sg->length; + extra[i].flags = n < out_sgs ? 0 : VRING_DESC_F_WRITE; + } + i++; } } @@ -1381,7 +1389,7 @@ unmap_release: err_idx = i; for (i = 0; i < err_idx; i++) - vring_unmap_desc_packed(vq, &desc[i]); + vring_unmap_extra_packed(vq, &extra[i]); free_desc: kfree(desc); @@ -1617,7 +1625,8 @@ static void detach_buf_packed(struct vring_virtqueue *vq, } if (vq->indirect) { - u32 len; + struct vring_desc_extra *extra; + u32 len, num; /* Free the indirect table, if any, now that it's unmapped. */ desc = state->indir_desc; @@ -1626,9 +1635,12 @@ static void detach_buf_packed(struct vring_virtqueue *vq, if (vring_need_unmap_buffer(vq)) { len = vq->packed.desc_extra[id].len; - for (i = 0; i < len / sizeof(struct vring_packed_desc); - i++) - vring_unmap_desc_packed(vq, &desc[i]); + num = len / sizeof(struct vring_packed_desc); + + extra = (struct vring_desc_extra *)&desc[num]; + + for (i = 0; i < num; i++) + vring_unmap_extra_packed(vq, &extra[i]); } kfree(desc); state->indir_desc = NULL; -- 2.49.0