| Message ID | 20240924013204.13763-3-xuanzhuo@linux.alibaba.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | virtio-net: support AF_XDP zero copy (tx) | expand |
On Tue, Sep 24, 2024 at 9:32 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > 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 <xuanzhuo@linux.alibaba.com> > --- > drivers/virtio/virtio_ring.c | 126 +++++++++++++++++------------------ > 1 file changed, 61 insertions(+), 65 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 228e9fbcba3f..62901bee97c0 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -67,9 +67,20 @@ > #define LAST_ADD_TIME_INVALID(vq) > #endif > > +struct vring_desc_extra { > + dma_addr_t addr; /* Descriptor DMA addr. */ > + u32 len; /* Descriptor length. */ > + u16 flags; /* Descriptor flags. */ > + u16 next; /* The next desc state in a list. */ > +}; > + > struct vring_desc_state_split { > void *data; /* Data for callback. */ > - struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ > + > + /* Indirect extra table and desc table, if any. These two will be > + * allocated together. So we won't stress more to the memory allocator. > + */ > + struct vring_desc_extra *indir; > }; > > struct vring_desc_state_packed { > @@ -79,13 +90,6 @@ struct vring_desc_state_packed { > u16 last; /* The last desc state in a list. */ > }; > > -struct vring_desc_extra { > - dma_addr_t addr; /* Descriptor DMA addr. */ > - u32 len; /* Descriptor length. */ > - u16 flags; /* Descriptor flags. */ > - u16 next; /* The next desc state in a list. */ > -}; > - > struct vring_virtqueue_split { > /* Actual memory layout for this queue. */ > struct vring vring; > @@ -440,38 +444,20 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num) > * Split ring specific functions - *_split(). > */ > > -static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq, > - const struct vring_desc *desc) > -{ > - u16 flags; > - > - if (!vring_need_unmap_buffer(vq)) > - return; > - > - flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); > - > - dma_unmap_page(vring_dma_dev(vq), > - virtio64_to_cpu(vq->vq.vdev, desc->addr), > - virtio32_to_cpu(vq->vq.vdev, desc->len), > - (flags & VRING_DESC_F_WRITE) ? > - DMA_FROM_DEVICE : DMA_TO_DEVICE); > -} > - > static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, > - unsigned int i) > + struct vring_desc_extra *extra) > { > - struct vring_desc_extra *extra = vq->split.desc_extra; > u16 flags; > > - flags = extra[i].flags; > + flags = extra->flags; > > if (flags & VRING_DESC_F_INDIRECT) { > if (!vq->use_dma_api) > goto out; > > dma_unmap_single(vring_dma_dev(vq), > - extra[i].addr, > - extra[i].len, > + extra->addr, > + extra->len, > (flags & VRING_DESC_F_WRITE) ? > DMA_FROM_DEVICE : DMA_TO_DEVICE); > } else { > @@ -479,20 +465,22 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, > goto out; > > dma_unmap_page(vring_dma_dev(vq), > - extra[i].addr, > - extra[i].len, > + extra->addr, > + extra->len, > (flags & VRING_DESC_F_WRITE) ? > DMA_FROM_DEVICE : DMA_TO_DEVICE); > } > > out: > - return extra[i].next; > + return extra->next; > } > > static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, > unsigned int total_sg, > + struct vring_desc_extra **pextra, This kind of API seems a little bit strange. In the caller we had: if (desc) { ... } else { extra = vq->split.desc_extra; } I'd move the assignment of the extra there to make the code more readable. > gfp_t gfp) > { > + struct vring_desc_extra *extra; > struct vring_desc *desc; > unsigned int i; > > @@ -503,40 +491,45 @@ static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, > */ > gfp &= ~__GFP_HIGHMEM; > > - desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp); > - if (!desc) > + extra = kmalloc_array(total_sg, sizeof(*desc) + sizeof(*extra), gfp); I'd suggest using kmalloc() directly, as it seems not an array where each descriptor is followed by one extra. > + if (!extra) > return NULL; > > - for (i = 0; i < total_sg; i++) > + desc = (struct vring_desc *)&extra[total_sg]; Still seems strange, I would rather make the descriptor come first then. This makes code more readable. And we can keep the indir_desc variable name. > + > + for (i = 0; i < total_sg; i++) { > desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1); > + extra[i].next = i + 1; > + } > + > + *pextra = extra; > + > return desc; > } > > static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq, > struct vring_desc *desc, > + struct vring_desc_extra *extra, > unsigned int i, > dma_addr_t addr, > unsigned int len, > u16 flags, > bool indirect) > { > - struct vring_virtqueue *vring = to_vvq(vq); > - struct vring_desc_extra *extra = vring->split.desc_extra; > u16 next; > > desc[i].flags = cpu_to_virtio16(vq->vdev, flags); > desc[i].addr = cpu_to_virtio64(vq->vdev, addr); > desc[i].len = cpu_to_virtio32(vq->vdev, len); > > - if (!indirect) { > - next = extra[i].next; > - desc[i].next = cpu_to_virtio16(vq->vdev, next); > + extra[i].addr = addr; > + extra[i].len = len; > + extra[i].flags = flags; > + > + next = extra[i].next; > > - extra[i].addr = addr; > - extra[i].len = len; > - extra[i].flags = flags; > - } else > - next = virtio16_to_cpu(vq->vdev, desc[i].next); > + if (!indirect) > + desc[i].next = cpu_to_virtio16(vq->vdev, next); Any chance we can remove the check for indirect here? For example, remove the assignment in alloc_indirect_split(). This would be more consistent with the way when we want to use desc_extra for both indirect and direct descriptors. > > return next; > } > @@ -551,6 +544,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > gfp_t gfp) > { > struct vring_virtqueue *vq = to_vvq(_vq); > + struct vring_desc_extra *extra; > struct scatterlist *sg; > struct vring_desc *desc; > unsigned int i, n, avail, descs_used, prev, err_idx; > @@ -574,7 +568,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > head = vq->free_head; > > if (virtqueue_use_indirect(vq, total_sg)) > - desc = alloc_indirect_split(_vq, total_sg, gfp); > + desc = alloc_indirect_split(_vq, total_sg, &extra, gfp); > else { > desc = NULL; > WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect); > @@ -589,6 +583,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > } else { > indirect = false; > desc = vq->split.vring.desc; > + extra = vq->split.desc_extra; > i = head; > descs_used = total_sg; > } > @@ -618,7 +613,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > /* Note that we trust indirect descriptor > * table since it use stream DMA mapping. > */ > - i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length, > + i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, sg->length, > VRING_DESC_F_NEXT, > indirect); > } > @@ -634,7 +629,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > /* Note that we trust indirect descriptor > * table since it use stream DMA mapping. > */ > - i = virtqueue_add_desc_split(_vq, desc, i, addr, > + i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, > sg->length, > VRING_DESC_F_NEXT | > VRING_DESC_F_WRITE, > @@ -660,6 +655,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > } > > virtqueue_add_desc_split(_vq, vq->split.vring.desc, > + vq->split.desc_extra, > head, addr, > total_sg * sizeof(struct vring_desc), > VRING_DESC_F_INDIRECT, > @@ -678,9 +674,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > /* Store token and indirect buffer state. */ > vq->split.desc_state[head].data = data; > if (indirect) > - vq->split.desc_state[head].indir_desc = desc; > + vq->split.desc_state[head].indir = extra; > else > - vq->split.desc_state[head].indir_desc = ctx; > + vq->split.desc_state[head].indir = ctx; > > /* Put entry in available array (but don't update avail->idx until they > * do sync). */ > @@ -716,11 +712,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > for (n = 0; n < total_sg; n++) { > if (i == err_idx) > break; > - if (indirect) { > - vring_unmap_one_split_indirect(vq, &desc[i]); > - i = virtio16_to_cpu(_vq->vdev, desc[i].next); > - } else > - i = vring_unmap_one_split(vq, i); > + > + i = vring_unmap_one_split(vq, &extra[i]); > } > > free_indirect: > @@ -765,22 +758,25 @@ static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) > static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > void **ctx) > { > + struct vring_desc_extra *extra; > unsigned int i, j; > __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); > > /* Clear data ptr. */ > vq->split.desc_state[head].data = NULL; > > + extra = vq->split.desc_extra; > + > /* Put back on free list: unmap first-level descriptors and find end */ > i = head; > > while (vq->split.vring.desc[i].flags & nextflag) { > - vring_unmap_one_split(vq, i); > + vring_unmap_one_split(vq, &extra[i]); > i = vq->split.desc_extra[i].next; > vq->vq.num_free++; > } > > - vring_unmap_one_split(vq, i); > + vring_unmap_one_split(vq, &extra[i]); > vq->split.desc_extra[i].next = vq->free_head; > vq->free_head = head; > > @@ -788,12 +784,12 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > vq->vq.num_free++; > > if (vq->indirect) { > - struct vring_desc *indir_desc = > - vq->split.desc_state[head].indir_desc; > u32 len; > > + extra = vq->split.desc_state[head].indir; > + > /* Free the indirect table, if any, now that it's unmapped. */ > - if (!indir_desc) > + if (!extra) > return; > > len = vq->split.desc_extra[head].len; > @@ -804,13 +800,13 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > > if (vring_need_unmap_buffer(vq)) { > for (j = 0; j < len / sizeof(struct vring_desc); j++) > - vring_unmap_one_split_indirect(vq, &indir_desc[j]); > + vring_unmap_one_split(vq, &extra[j]); > } > > - kfree(indir_desc); > - vq->split.desc_state[head].indir_desc = NULL; > + kfree(extra); > + vq->split.desc_state[head].indir = NULL; > } else if (ctx) { > - *ctx = vq->split.desc_state[head].indir_desc; > + *ctx = vq->split.desc_state[head].indir; > } > } > > -- > 2.32.0.3.g01195cf9f > Thanks
Will fix for all commets in next version. Thanks. On Tue, 24 Sep 2024 15:34:57 +0800, Jason Wang <jasowang@redhat.com> wrote: > On Tue, Sep 24, 2024 at 9:32 AM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote: > > > > 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 <xuanzhuo@linux.alibaba.com> > > --- > > drivers/virtio/virtio_ring.c | 126 +++++++++++++++++------------------ > > 1 file changed, 61 insertions(+), 65 deletions(-) > > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > > index 228e9fbcba3f..62901bee97c0 100644 > > --- a/drivers/virtio/virtio_ring.c > > +++ b/drivers/virtio/virtio_ring.c > > @@ -67,9 +67,20 @@ > > #define LAST_ADD_TIME_INVALID(vq) > > #endif > > > > +struct vring_desc_extra { > > + dma_addr_t addr; /* Descriptor DMA addr. */ > > + u32 len; /* Descriptor length. */ > > + u16 flags; /* Descriptor flags. */ > > + u16 next; /* The next desc state in a list. */ > > +}; > > + > > struct vring_desc_state_split { > > void *data; /* Data for callback. */ > > - struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ > > + > > + /* Indirect extra table and desc table, if any. These two will be > > + * allocated together. So we won't stress more to the memory allocator. > > + */ > > + struct vring_desc_extra *indir; > > }; > > > > struct vring_desc_state_packed { > > @@ -79,13 +90,6 @@ struct vring_desc_state_packed { > > u16 last; /* The last desc state in a list. */ > > }; > > > > -struct vring_desc_extra { > > - dma_addr_t addr; /* Descriptor DMA addr. */ > > - u32 len; /* Descriptor length. */ > > - u16 flags; /* Descriptor flags. */ > > - u16 next; /* The next desc state in a list. */ > > -}; > > - > > struct vring_virtqueue_split { > > /* Actual memory layout for this queue. */ > > struct vring vring; > > @@ -440,38 +444,20 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num) > > * Split ring specific functions - *_split(). > > */ > > > > -static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq, > > - const struct vring_desc *desc) > > -{ > > - u16 flags; > > - > > - if (!vring_need_unmap_buffer(vq)) > > - return; > > - > > - flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); > > - > > - dma_unmap_page(vring_dma_dev(vq), > > - virtio64_to_cpu(vq->vq.vdev, desc->addr), > > - virtio32_to_cpu(vq->vq.vdev, desc->len), > > - (flags & VRING_DESC_F_WRITE) ? > > - DMA_FROM_DEVICE : DMA_TO_DEVICE); > > -} > > - > > static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, > > - unsigned int i) > > + struct vring_desc_extra *extra) > > { > > - struct vring_desc_extra *extra = vq->split.desc_extra; > > u16 flags; > > > > - flags = extra[i].flags; > > + flags = extra->flags; > > > > if (flags & VRING_DESC_F_INDIRECT) { > > if (!vq->use_dma_api) > > goto out; > > > > dma_unmap_single(vring_dma_dev(vq), > > - extra[i].addr, > > - extra[i].len, > > + extra->addr, > > + extra->len, > > (flags & VRING_DESC_F_WRITE) ? > > DMA_FROM_DEVICE : DMA_TO_DEVICE); > > } else { > > @@ -479,20 +465,22 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, > > goto out; > > > > dma_unmap_page(vring_dma_dev(vq), > > - extra[i].addr, > > - extra[i].len, > > + extra->addr, > > + extra->len, > > (flags & VRING_DESC_F_WRITE) ? > > DMA_FROM_DEVICE : DMA_TO_DEVICE); > > } > > > > out: > > - return extra[i].next; > > + return extra->next; > > } > > > > static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, > > unsigned int total_sg, > > + struct vring_desc_extra **pextra, > > This kind of API seems a little bit strange. In the caller we had: > > if (desc) { > ... > } else { > extra = vq->split.desc_extra; > } > > I'd move the assignment of the extra there to make the code more readable. > > > gfp_t gfp) > > { > > + struct vring_desc_extra *extra; > > struct vring_desc *desc; > > unsigned int i; > > > > @@ -503,40 +491,45 @@ static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, > > */ > > gfp &= ~__GFP_HIGHMEM; > > > > - desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp); > > - if (!desc) > > + extra = kmalloc_array(total_sg, sizeof(*desc) + sizeof(*extra), gfp); > > I'd suggest using kmalloc() directly, as it seems not an array where > each descriptor is followed by one extra. > > > + if (!extra) > > return NULL; > > > > - for (i = 0; i < total_sg; i++) > > + desc = (struct vring_desc *)&extra[total_sg]; > > Still seems strange, I would rather make the descriptor come first > then. This makes code more readable. And we can keep the indir_desc > variable name. > > > + > > + for (i = 0; i < total_sg; i++) { > > desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1); > > + extra[i].next = i + 1; > > + } > > + > > + *pextra = extra; > > + > > return desc; > > } > > > > static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq, > > struct vring_desc *desc, > > + struct vring_desc_extra *extra, > > unsigned int i, > > dma_addr_t addr, > > unsigned int len, > > u16 flags, > > bool indirect) > > { > > - struct vring_virtqueue *vring = to_vvq(vq); > > - struct vring_desc_extra *extra = vring->split.desc_extra; > > u16 next; > > > > desc[i].flags = cpu_to_virtio16(vq->vdev, flags); > > desc[i].addr = cpu_to_virtio64(vq->vdev, addr); > > desc[i].len = cpu_to_virtio32(vq->vdev, len); > > > > - if (!indirect) { > > - next = extra[i].next; > > - desc[i].next = cpu_to_virtio16(vq->vdev, next); > > + extra[i].addr = addr; > > + extra[i].len = len; > > + extra[i].flags = flags; > > + > > + next = extra[i].next; > > > > - extra[i].addr = addr; > > - extra[i].len = len; > > - extra[i].flags = flags; > > - } else > > - next = virtio16_to_cpu(vq->vdev, desc[i].next); > > + if (!indirect) > > + desc[i].next = cpu_to_virtio16(vq->vdev, next); > > Any chance we can remove the check for indirect here? For example, > remove the assignment in alloc_indirect_split(). This would be more > consistent with the way when we want to use desc_extra for both > indirect and direct descriptors. > > > > > return next; > > } > > @@ -551,6 +544,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > gfp_t gfp) > > { > > struct vring_virtqueue *vq = to_vvq(_vq); > > + struct vring_desc_extra *extra; > > struct scatterlist *sg; > > struct vring_desc *desc; > > unsigned int i, n, avail, descs_used, prev, err_idx; > > @@ -574,7 +568,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > head = vq->free_head; > > > > if (virtqueue_use_indirect(vq, total_sg)) > > - desc = alloc_indirect_split(_vq, total_sg, gfp); > > + desc = alloc_indirect_split(_vq, total_sg, &extra, gfp); > > else { > > desc = NULL; > > WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect); > > @@ -589,6 +583,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > } else { > > indirect = false; > > desc = vq->split.vring.desc; > > + extra = vq->split.desc_extra; > > i = head; > > descs_used = total_sg; > > } > > @@ -618,7 +613,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > /* Note that we trust indirect descriptor > > * table since it use stream DMA mapping. > > */ > > - i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length, > > + i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, sg->length, > > VRING_DESC_F_NEXT, > > indirect); > > } > > @@ -634,7 +629,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > /* Note that we trust indirect descriptor > > * table since it use stream DMA mapping. > > */ > > - i = virtqueue_add_desc_split(_vq, desc, i, addr, > > + i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, > > sg->length, > > VRING_DESC_F_NEXT | > > VRING_DESC_F_WRITE, > > @@ -660,6 +655,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > } > > > > virtqueue_add_desc_split(_vq, vq->split.vring.desc, > > + vq->split.desc_extra, > > head, addr, > > total_sg * sizeof(struct vring_desc), > > VRING_DESC_F_INDIRECT, > > @@ -678,9 +674,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > /* Store token and indirect buffer state. */ > > vq->split.desc_state[head].data = data; > > if (indirect) > > - vq->split.desc_state[head].indir_desc = desc; > > + vq->split.desc_state[head].indir = extra; > > else > > - vq->split.desc_state[head].indir_desc = ctx; > > + vq->split.desc_state[head].indir = ctx; > > > > /* Put entry in available array (but don't update avail->idx until they > > * do sync). */ > > @@ -716,11 +712,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > > for (n = 0; n < total_sg; n++) { > > if (i == err_idx) > > break; > > - if (indirect) { > > - vring_unmap_one_split_indirect(vq, &desc[i]); > > - i = virtio16_to_cpu(_vq->vdev, desc[i].next); > > - } else > > - i = vring_unmap_one_split(vq, i); > > + > > + i = vring_unmap_one_split(vq, &extra[i]); > > } > > > > free_indirect: > > @@ -765,22 +758,25 @@ static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) > > static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > > void **ctx) > > { > > + struct vring_desc_extra *extra; > > unsigned int i, j; > > __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); > > > > /* Clear data ptr. */ > > vq->split.desc_state[head].data = NULL; > > > > + extra = vq->split.desc_extra; > > + > > /* Put back on free list: unmap first-level descriptors and find end */ > > i = head; > > > > while (vq->split.vring.desc[i].flags & nextflag) { > > - vring_unmap_one_split(vq, i); > > + vring_unmap_one_split(vq, &extra[i]); > > i = vq->split.desc_extra[i].next; > > vq->vq.num_free++; > > } > > > > - vring_unmap_one_split(vq, i); > > + vring_unmap_one_split(vq, &extra[i]); > > vq->split.desc_extra[i].next = vq->free_head; > > vq->free_head = head; > > > > @@ -788,12 +784,12 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > > vq->vq.num_free++; > > > > if (vq->indirect) { > > - struct vring_desc *indir_desc = > > - vq->split.desc_state[head].indir_desc; > > u32 len; > > > > + extra = vq->split.desc_state[head].indir; > > + > > /* Free the indirect table, if any, now that it's unmapped. */ > > - if (!indir_desc) > > + if (!extra) > > return; > > > > len = vq->split.desc_extra[head].len; > > @@ -804,13 +800,13 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > > > > if (vring_need_unmap_buffer(vq)) { > > for (j = 0; j < len / sizeof(struct vring_desc); j++) > > - vring_unmap_one_split_indirect(vq, &indir_desc[j]); > > + vring_unmap_one_split(vq, &extra[j]); > > } > > > > - kfree(indir_desc); > > - vq->split.desc_state[head].indir_desc = NULL; > > + kfree(extra); > > + vq->split.desc_state[head].indir = NULL; > > } else if (ctx) { > > - *ctx = vq->split.desc_state[head].indir_desc; > > + *ctx = vq->split.desc_state[head].indir; > > } > > } > > > > -- > > 2.32.0.3.g01195cf9f > > > > Thanks > >
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 228e9fbcba3f..62901bee97c0 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -67,9 +67,20 @@ #define LAST_ADD_TIME_INVALID(vq) #endif +struct vring_desc_extra { + dma_addr_t addr; /* Descriptor DMA addr. */ + u32 len; /* Descriptor length. */ + u16 flags; /* Descriptor flags. */ + u16 next; /* The next desc state in a list. */ +}; + struct vring_desc_state_split { void *data; /* Data for callback. */ - struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ + + /* Indirect extra table and desc table, if any. These two will be + * allocated together. So we won't stress more to the memory allocator. + */ + struct vring_desc_extra *indir; }; struct vring_desc_state_packed { @@ -79,13 +90,6 @@ struct vring_desc_state_packed { u16 last; /* The last desc state in a list. */ }; -struct vring_desc_extra { - dma_addr_t addr; /* Descriptor DMA addr. */ - u32 len; /* Descriptor length. */ - u16 flags; /* Descriptor flags. */ - u16 next; /* The next desc state in a list. */ -}; - struct vring_virtqueue_split { /* Actual memory layout for this queue. */ struct vring vring; @@ -440,38 +444,20 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num) * Split ring specific functions - *_split(). */ -static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq, - const struct vring_desc *desc) -{ - u16 flags; - - if (!vring_need_unmap_buffer(vq)) - return; - - flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); - - dma_unmap_page(vring_dma_dev(vq), - virtio64_to_cpu(vq->vq.vdev, desc->addr), - virtio32_to_cpu(vq->vq.vdev, desc->len), - (flags & VRING_DESC_F_WRITE) ? - DMA_FROM_DEVICE : DMA_TO_DEVICE); -} - static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, - unsigned int i) + struct vring_desc_extra *extra) { - struct vring_desc_extra *extra = vq->split.desc_extra; u16 flags; - flags = extra[i].flags; + flags = extra->flags; if (flags & VRING_DESC_F_INDIRECT) { if (!vq->use_dma_api) goto out; dma_unmap_single(vring_dma_dev(vq), - extra[i].addr, - extra[i].len, + extra->addr, + extra->len, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { @@ -479,20 +465,22 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, goto out; dma_unmap_page(vring_dma_dev(vq), - extra[i].addr, - extra[i].len, + extra->addr, + extra->len, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } out: - return extra[i].next; + return extra->next; } static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, unsigned int total_sg, + struct vring_desc_extra **pextra, gfp_t gfp) { + struct vring_desc_extra *extra; struct vring_desc *desc; unsigned int i; @@ -503,40 +491,45 @@ static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, */ gfp &= ~__GFP_HIGHMEM; - desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp); - if (!desc) + extra = kmalloc_array(total_sg, sizeof(*desc) + sizeof(*extra), gfp); + if (!extra) return NULL; - for (i = 0; i < total_sg; i++) + desc = (struct vring_desc *)&extra[total_sg]; + + for (i = 0; i < total_sg; i++) { desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1); + extra[i].next = i + 1; + } + + *pextra = extra; + return desc; } static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq, struct vring_desc *desc, + struct vring_desc_extra *extra, unsigned int i, dma_addr_t addr, unsigned int len, u16 flags, bool indirect) { - struct vring_virtqueue *vring = to_vvq(vq); - struct vring_desc_extra *extra = vring->split.desc_extra; u16 next; desc[i].flags = cpu_to_virtio16(vq->vdev, flags); desc[i].addr = cpu_to_virtio64(vq->vdev, addr); desc[i].len = cpu_to_virtio32(vq->vdev, len); - if (!indirect) { - next = extra[i].next; - desc[i].next = cpu_to_virtio16(vq->vdev, next); + extra[i].addr = addr; + extra[i].len = len; + extra[i].flags = flags; + + next = extra[i].next; - extra[i].addr = addr; - extra[i].len = len; - extra[i].flags = flags; - } else - next = virtio16_to_cpu(vq->vdev, desc[i].next); + if (!indirect) + desc[i].next = cpu_to_virtio16(vq->vdev, next); return next; } @@ -551,6 +544,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, gfp_t gfp) { struct vring_virtqueue *vq = to_vvq(_vq); + struct vring_desc_extra *extra; struct scatterlist *sg; struct vring_desc *desc; unsigned int i, n, avail, descs_used, prev, err_idx; @@ -574,7 +568,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, head = vq->free_head; if (virtqueue_use_indirect(vq, total_sg)) - desc = alloc_indirect_split(_vq, total_sg, gfp); + desc = alloc_indirect_split(_vq, total_sg, &extra, gfp); else { desc = NULL; WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect); @@ -589,6 +583,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, } else { indirect = false; desc = vq->split.vring.desc; + extra = vq->split.desc_extra; i = head; descs_used = total_sg; } @@ -618,7 +613,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, /* Note that we trust indirect descriptor * table since it use stream DMA mapping. */ - i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length, + i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, sg->length, VRING_DESC_F_NEXT, indirect); } @@ -634,7 +629,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, /* Note that we trust indirect descriptor * table since it use stream DMA mapping. */ - i = virtqueue_add_desc_split(_vq, desc, i, addr, + i = virtqueue_add_desc_split(_vq, desc, extra, i, addr, sg->length, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE, @@ -660,6 +655,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, } virtqueue_add_desc_split(_vq, vq->split.vring.desc, + vq->split.desc_extra, head, addr, total_sg * sizeof(struct vring_desc), VRING_DESC_F_INDIRECT, @@ -678,9 +674,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, /* Store token and indirect buffer state. */ vq->split.desc_state[head].data = data; if (indirect) - vq->split.desc_state[head].indir_desc = desc; + vq->split.desc_state[head].indir = extra; else - vq->split.desc_state[head].indir_desc = ctx; + vq->split.desc_state[head].indir = ctx; /* Put entry in available array (but don't update avail->idx until they * do sync). */ @@ -716,11 +712,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, for (n = 0; n < total_sg; n++) { if (i == err_idx) break; - if (indirect) { - vring_unmap_one_split_indirect(vq, &desc[i]); - i = virtio16_to_cpu(_vq->vdev, desc[i].next); - } else - i = vring_unmap_one_split(vq, i); + + i = vring_unmap_one_split(vq, &extra[i]); } free_indirect: @@ -765,22 +758,25 @@ static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, void **ctx) { + struct vring_desc_extra *extra; unsigned int i, j; __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); /* Clear data ptr. */ vq->split.desc_state[head].data = NULL; + extra = vq->split.desc_extra; + /* Put back on free list: unmap first-level descriptors and find end */ i = head; while (vq->split.vring.desc[i].flags & nextflag) { - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, &extra[i]); i = vq->split.desc_extra[i].next; vq->vq.num_free++; } - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, &extra[i]); vq->split.desc_extra[i].next = vq->free_head; vq->free_head = head; @@ -788,12 +784,12 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, vq->vq.num_free++; if (vq->indirect) { - struct vring_desc *indir_desc = - vq->split.desc_state[head].indir_desc; u32 len; + extra = vq->split.desc_state[head].indir; + /* Free the indirect table, if any, now that it's unmapped. */ - if (!indir_desc) + if (!extra) return; len = vq->split.desc_extra[head].len; @@ -804,13 +800,13 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, if (vring_need_unmap_buffer(vq)) { for (j = 0; j < len / sizeof(struct vring_desc); j++) - vring_unmap_one_split_indirect(vq, &indir_desc[j]); + vring_unmap_one_split(vq, &extra[j]); } - kfree(indir_desc); - vq->split.desc_state[head].indir_desc = NULL; + kfree(extra); + vq->split.desc_state[head].indir = NULL; } else if (ctx) { - *ctx = vq->split.desc_state[head].indir_desc; + *ctx = vq->split.desc_state[head].indir; } }
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 <xuanzhuo@linux.alibaba.com> --- drivers/virtio/virtio_ring.c | 126 +++++++++++++++++------------------ 1 file changed, 61 insertions(+), 65 deletions(-)