search for: sg_dma_len

Hi Logan/All, I have added a check for the sg_dma_len == 0 : """ } __sgt_iter(struct scatterlist *sgl, bool dma) { struct sgt_iter s = { .sgp = sgl }; + if (sgl && sg_dma_len(sgl) == 0) + s.sgp = NULL; if (s.sgp) { ..... """ at location [1]. but it doens't fix the...

On Thu, 27 Aug 2020 at 22:36, Logan Gunthorpe <logang at deltatee.com> wrote: > > > > On 2020-08-23 6:04 p.m., Tom Murphy wrote: > > I have added a check for the sg_dma_len == 0 : > > """ > > } __sgt_iter(struct scatterlist *sgl, bool dma) { > > struct sgt_iter s = { .sgp = sgl }; > > > > + if (sgl && sg_dma_len(sgl) == 0) > > + s.sgp = NULL; > > > > if (s.sgp) { &g...

..., max_len = dma_get_max_seg_size(dev); - int i, count = 0; + int i; for_each_sg(sg, s, nents, i) { /* Restore this segment's original unaligned fields first */ @@ -862,39 +861,16 @@ static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents, unsigned int s_length = sg_dma_len(s); unsigned int s_iova_len = s->length; + if (i > 0) + cur = sg_next(cur); + s->offset += s_iova_off; s->length = s_length; - sg_dma_address(s) = DMA_MAPPING_ERROR; - sg_dma_len(s) = 0; - - /* - * Now fill in the real DMA data. If... - * - there is a valid output s...

...+27,19 @@ static __always_inline struct sgt_iter { > >>>>>> } __sgt_iter(struct scatterlist *sgl, bool dma) { > >>>>>> struct sgt_iter s = { .sgp = sgl }; > >>>>>> > >>>>>> + if (sgl && !sg_dma_len(s.sgp)) > >>>>> > >>>>> I'd extend the condition to be, just to be safe: > >>>>> if (dma && sgl && !sg_dma_len(s.sgp)) > >>>>> > >>>> > >>>> Right, good catch, that's...

...15/i915_scatterlist.h > >>> @@ -27,13 +27,19 @@ static __always_inline struct sgt_iter { > >>> } __sgt_iter(struct scatterlist *sgl, bool dma) { > >>> struct sgt_iter s = { .sgp = sgl }; > >>> > >>> + if (sgl && !sg_dma_len(s.sgp)) > >> > >> I'd extend the condition to be, just to be safe: > >> if (dma && sgl && !sg_dma_len(s.sgp)) > >> > > > > Right, good catch, that's definitely necessary. > > > >>> + s.sgp =...

...f (!vring_use_dma_api(vq->vq.vdev)) > return (dma_addr_t)sg_phys(sg); > > + /* If the sg is already mapped, return the DMA address */ How come we even reach this code for rpmsg? Does vring_use_dma_api return true for rpmsg? > + if (sg_dma_address(sg)) { > + sg->length = sg_dma_len(sg); > + return sg_dma_address(sg); > + } > + Is there a rule that says 0 is not a valid address? > /* > * We can't use dma_map_sg, because we don't use scatterlists in > * the way it expects (we don't guarantee that the scatterlist > -- > 1.9.1

...f (!vring_use_dma_api(vq->vq.vdev)) > return (dma_addr_t)sg_phys(sg); > > + /* If the sg is already mapped, return the DMA address */ How come we even reach this code for rpmsg? Does vring_use_dma_api return true for rpmsg? > + if (sg_dma_address(sg)) { > + sg->length = sg_dma_len(sg); > + return sg_dma_address(sg); > + } > + Is there a rule that says 0 is not a valid address? > /* > * We can't use dma_map_sg, because we don't use scatterlists in > * the way it expects (we don't guarantee that the scatterlist > -- > 1.9.1

RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote. In this case, as there is no pages setup in the dma_alloc_coherent(), we cannot get the physical address back from the virtual address, and thus, we can set the sg_dma_addr to store the DMA address and mark it already DMA mapped. When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page(). The issue

RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote. In this case, as there is no pages setup in the dma_alloc_coherent(), we cannot get the physical address back from the virtual address, and thus, we can set the sg_dma_addr to store the DMA address and mark it already DMA mapped. When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page(). The issue

RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote. In this case, as there is no pages setup in the dma_alloc_coherent(), we cannot get the physical address back from the virtual address, and thus, we can set the sg_dma_addr to store the DMA address and mark it already DMA mapped. When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page(). The issue

RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote. In this case, as there is no pages setup in the dma_alloc_coherent(), we cannot get the physical address back from the virtual address, and thus, we can set the sg_dma_addr to store the DMA address and mark it already DMA mapped. When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page(). The issue

RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote. In this case, as there is no pages setup in the dma_alloc_coherent(), we cannot get the physical address back from the virtual address, and thus, we can set the sg_dma_addr to store the DMA address and mark it already DMA mapped. When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page(). The issue

RPMsg uses dma_alloc_coherent() to allocate memory to shared with the remote. In this case, as there is no pages setup in the dma_alloc_coherent(), we cannot get the physical address back from the virtual address, and thus, we can set the sg_dma_addr to store the DMA address and mark it already DMA mapped. When virtio vring sees the sg_dma_addr is ready set, do not call dma_map_page(). The issue

...ls in the kernel seems to > indicate checking for 0 for errors and then ignoring the non-zero return > is a common pattern. Are you sure it's okay to make the change you're > proposing? Various code uses tricks like just iterating the mapped list until the first segment with zero sg_dma_len(). Others may well simply have bugs. Robin. > Anyway, due to the time of year and all, I'd like to ask you to file a > bug against i915 at [1] so this is not forgotten, and please let's not > merge the changes before this is resolved. > > > Thanks, > Jani. > &gt...

From: "Edgar E. Iglesias" <edgar.iglesias at xilinx.com> I'm trying to run rpmsg and remoteproc on the ZynqMP (arm64) but I'm hitting a DMA/mm error. The issue was discussed here: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333050.html Russel King pointed out that the arm64 is not doing anything wrong by returning vmapped memory (which is incompatible

From: "Edgar E. Iglesias" <edgar.iglesias at xilinx.com> I'm trying to run rpmsg and remoteproc on the ZynqMP (arm64) but I'm hitting a DMA/mm error. The issue was discussed here: http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/333050.html Russel King pointed out that the arm64 is not doing anything wrong by returning vmapped memory (which is incompatible

...) - 1)) >> bits; u32 max = 1 << (vmm->pgt_bits - bits); @@ -98,7 +99,7 @@ nouveau_vm_map_sg_table(struct nouveau_vma *vma, u64 delta, u64 length, for_each_sg(mem->sg->sgl, sg, mem->sg->nents, i) { struct nouveau_gpuobj *pgt = vm->pgt[pde].obj[big]; - sglen = sg_dma_len(sg) >> PAGE_SHIFT; + sglen = sg_dma_len(sg) >> shift; end = pte + sglen; if (unlikely(end >= max)) @@ -106,7 +107,7 @@ nouveau_vm_map_sg_table(struct nouveau_vma *vma, u64 delta, u64 length, len = end - pte; for (m = 0; m < len; m++) { - dma_addr_t addr = sg_dma...

...u32 pte = offset & ((1 << vmm->pgt_bits) - 1); + u32 max = 1 << vmm->pgt_bits; + u32 end, len, cardlen; int i; struct scatterlist *sg; - for_each_sg(mem->sg->sgl, sg, mem->sg->nents, i) { - struct nouveau_gpuobj *pgt = vm->pgt[pde].obj[big]; - sglen = sg_dma_len(sg) >> PAGE_SHIFT; + /* We don't handle "big" pages here */ + if (WARN_ON(shift != vmm->spg_shift || shift > PAGE_SHIFT)) + return; - end = pte + sglen; - if (unlikely(end >= max)) - end = max; - len = end - pte; + /* We dont' handle objects that aren't...

...m->pgt_bits - bits); > > @@ -98,7 +99,7 @@ nouveau_vm_map_sg_table(struct nouveau_vma *vma, u64 delta, u64 length, > > > > for_each_sg(mem->sg->sgl, sg, mem->sg->nents, i) { > > struct nouveau_gpuobj *pgt = vm->pgt[pde].obj[big]; > > - sglen = sg_dma_len(sg) >> PAGE_SHIFT; > > + sglen = sg_dma_len(sg) >> shift; > > > > end = pte + sglen; > > if (unlikely(end >= max)) > Please add a WARN_ON(big); in map_sg and map_sg_table if you do this. So that's debatable :-) The above code is map_sg. Argua...

...eturn vrp->bufs_dma + offset; > +} > + > +static inline void rpmsg_msg_sg_init(struct virtproc_info *vrp, > + struct scatterlist *sg, > + void *msg, unsigned int len) > +{ > + sg_init_table(sg, 1); > + sg_dma_address(sg) = msg_dma_address(vrp, msg); > + sg_dma_len(sg) = len; > +} > + > /* for more info, see below documentation of rpmsg_create_ept() */ > static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp, > struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb, > @@ -754,12 +770,12 @@ int rpmsg_send_offchannel_raw(struct...