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RDMA/core: Add umem "is_contiguous" and "start_dma_addr" helpers 

In some cases drivers may need to check if a given umem is contiguous.
Add a helper function in core code so that drivers don't need to deal
with umem or scatter-gather lists structure.
Additionally add a helper for getting umem's start DMA address and use
it in other helper functions that open code it.

Signed-off-by: Michael Margolin <mrgolin@amazon.com>
Link: https://patch.msgid.link/20250708202308.24783-3-mrgolin@amazon.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
This commit is contained in:
Michael Margolin 2025-07-08 20:23:07 +00:00 committed by Leon Romanovsky
parent 1a40c362ae
commit c897c2c8b8
1 changed files with 21 additions and 4 deletions
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25
include/rdma/ib_umem.h
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@ -52,11 +52,15 @@ static inline int ib_umem_offset(struct ib_umem *umem)
return umem->address & ~PAGE_MASK;
}
static inline dma_addr_t ib_umem_start_dma_addr(struct ib_umem *umem)
{
return sg_dma_address(umem->sgt_append.sgt.sgl) + ib_umem_offset(umem);
}
static inline unsigned long ib_umem_dma_offset(struct ib_umem *umem,
unsigned long pgsz)
{
return (sg_dma_address(umem->sgt_append.sgt.sgl) + ib_umem_offset(umem)) &
(pgsz - 1);
return ib_umem_start_dma_addr(umem) & (pgsz - 1);
}
static inline size_t ib_umem_num_dma_blocks(struct ib_umem *umem,
@ -135,14 +139,27 @@ static inline unsigned long ib_umem_find_best_pgoff(struct ib_umem *umem,
unsigned long pgsz_bitmap,
u64 pgoff_bitmask)
{
struct scatterlist *sg = umem->sgt_append.sgt.sgl;
dma_addr_t dma_addr;
dma_addr = sg_dma_address(sg) + (umem->address & ~PAGE_MASK);
dma_addr = ib_umem_start_dma_addr(umem);
return ib_umem_find_best_pgsz(umem, pgsz_bitmap,
dma_addr & pgoff_bitmask);
}
static inline bool ib_umem_is_contiguous(struct ib_umem *umem)
{
dma_addr_t dma_addr;
unsigned long pgsz;
/*
* Select the smallest aligned page that can contain the whole umem if
* it was contiguous.
*/
dma_addr = ib_umem_start_dma_addr(umem);
pgsz = roundup_pow_of_two((dma_addr ^ (umem->length - 1 + dma_addr)) + 1);
return !!ib_umem_find_best_pgoff(umem, pgsz, U64_MAX);
}
struct ib_umem_dmabuf *ib_umem_dmabuf_get(struct ib_device *device,
unsigned long offset, size_t size,
int fd, int access,