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// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/*
* Copyright (c) 2020 Intel Corporation. All rights reserved.
*/
#include <linux/dma-buf.h>
#include <linux/dma-resv.h>
#include <linux/dma-mapping.h>
#include "uverbs.h"
int ib_umem_dmabuf_map_pages(struct ib_umem_dmabuf *umem_dmabuf)
{
struct sg_table *sgt;
struct scatterlist *sg;
struct dma_fence *fence;
unsigned long start, end, cur = 0;
unsigned int nmap = 0;
int i;
dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
if (umem_dmabuf->sgt)
goto wait_fence;
sgt = dma_buf_map_attachment(umem_dmabuf->attach, DMA_BIDIRECTIONAL);
if (IS_ERR(sgt))
return PTR_ERR(sgt);
/* modify the sg list in-place to match umem address and length */
start = ALIGN_DOWN(umem_dmabuf->umem.address, PAGE_SIZE);
end = ALIGN(umem_dmabuf->umem.address + umem_dmabuf->umem.length,
PAGE_SIZE);
for_each_sgtable_dma_sg(sgt, sg, i) {
if (start < cur + sg_dma_len(sg) && cur < end)
nmap++;
if (cur <= start && start < cur + sg_dma_len(sg)) {
unsigned long offset = start - cur;
umem_dmabuf->first_sg = sg;
umem_dmabuf->first_sg_offset = offset;
sg_dma_address(sg) += offset;
sg_dma_len(sg) -= offset;
cur += offset;
}
if (cur < end && end <= cur + sg_dma_len(sg)) {
unsigned long trim = cur + sg_dma_len(sg) - end;
umem_dmabuf->last_sg = sg;
umem_dmabuf->last_sg_trim = trim;
sg_dma_len(sg) -= trim;
break;
}
cur += sg_dma_len(sg);
}
umem_dmabuf->umem.sgt_append.sgt.sgl = umem_dmabuf->first_sg;
umem_dmabuf->umem.sgt_append.sgt.nents = nmap;
umem_dmabuf->sgt = sgt;
wait_fence:
/*
* Although the sg list is valid now, the content of the pages
* may be not up-to-date. Wait for the exporter to finish
* the migration.
*/
fence = dma_resv_excl_fence(umem_dmabuf->attach->dmabuf->resv);
if (fence)
return dma_fence_wait(fence, false);
return 0;
}
EXPORT_SYMBOL(ib_umem_dmabuf_map_pages);
void ib_umem_dmabuf_unmap_pages(struct ib_umem_dmabuf *umem_dmabuf)
{
dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
if (!umem_dmabuf->sgt)
return;
/* retore the original sg list */
if (umem_dmabuf->first_sg) {
sg_dma_address(umem_dmabuf->first_sg) -=
umem_dmabuf->first_sg_offset;
sg_dma_len(umem_dmabuf->first_sg) +=
umem_dmabuf->first_sg_offset;
umem_dmabuf->first_sg = NULL;
umem_dmabuf->first_sg_offset = 0;
}
if (umem_dmabuf->last_sg) {
sg_dma_len(umem_dmabuf->last_sg) +=
umem_dmabuf->last_sg_trim;
umem_dmabuf->last_sg = NULL;
umem_dmabuf->last_sg_trim = 0;
}
dma_buf_unmap_attachment(umem_dmabuf->attach, umem_dmabuf->sgt,
DMA_BIDIRECTIONAL);
umem_dmabuf->sgt = NULL;
}
EXPORT_SYMBOL(ib_umem_dmabuf_unmap_pages);
struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
unsigned long offset, size_t size,
int fd, int access,
const struct dma_buf_attach_ops *ops)
{
struct dma_buf *dmabuf;
struct ib_umem_dmabuf *umem_dmabuf;
struct ib_umem *umem;
unsigned long end;
struct ib_umem_dmabuf *ret = ERR_PTR(-EINVAL);
if (check_add_overflow(offset, (unsigned long)size, &end))
return ret;
if (unlikely(!ops || !ops->move_notify))
return ret;
dmabuf = dma_buf_get(fd);
if (IS_ERR(dmabuf))
return ERR_CAST(dmabuf);
if (dmabuf->size < end)
goto out_release_dmabuf;
umem_dmabuf = kzalloc(sizeof(*umem_dmabuf), GFP_KERNEL);
if (!umem_dmabuf) {
ret = ERR_PTR(-ENOMEM);
goto out_release_dmabuf;
}
umem = &umem_dmabuf->umem;
umem->ibdev = device;
umem->length = size;
umem->address = offset;
umem->writable = ib_access_writable(access);
umem->is_dmabuf = 1;
if (!ib_umem_num_pages(umem))
goto out_free_umem;
umem_dmabuf->attach = dma_buf_dynamic_attach(
dmabuf,
device->dma_device,
ops,
umem_dmabuf);
if (IS_ERR(umem_dmabuf->attach)) {
ret = ERR_CAST(umem_dmabuf->attach);
goto out_free_umem;
}
return umem_dmabuf;
out_free_umem:
kfree(umem_dmabuf);
out_release_dmabuf:
dma_buf_put(dmabuf);
return ret;
}
EXPORT_SYMBOL(ib_umem_dmabuf_get);
void ib_umem_dmabuf_release(struct ib_umem_dmabuf *umem_dmabuf)
{
struct dma_buf *dmabuf = umem_dmabuf->attach->dmabuf;
dma_resv_lock(dmabuf->resv, NULL);
ib_umem_dmabuf_unmap_pages(umem_dmabuf);
dma_resv_unlock(dmabuf->resv);
dma_buf_detach(dmabuf, umem_dmabuf->attach);
dma_buf_put(dmabuf);
kfree(umem_dmabuf);
}
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