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authorJason Gunthorpe <jgg@nvidia.com>2020-09-05 01:41:47 +0300
committerJason Gunthorpe <jgg@nvidia.com>2020-09-11 16:24:53 +0300
commita665aca89a411115e35ea937c2d3fb2ee4f5a701 (patch)
tree79c8a3e6ba1b0df6d1cfe1e1067a40b72bc1f942 /include/rdma
parent89603f7e7e5a6b719f1a163a05bd8a9231b58318 (diff)
downloadlinux-a665aca89a411115e35ea937c2d3fb2ee4f5a701.tar.xz
RDMA/umem: Split ib_umem_num_pages() into ib_umem_num_dma_blocks()
ib_umem_num_pages() should only be used by things working with the SGL in CPU pages directly. Drivers building DMA lists should use the new ib_num_dma_blocks() which returns the number of blocks rdma_umem_for_each_block() will return. To make this general for DMA drivers requires a different implementation. Computing DMA block count based on umem->address only works if the requested page size is < PAGE_SIZE and/or the IOVA == umem->address. Instead the number of DMA pages should be computed in the IOVA address space, not umem->address. Thus the IOVA has to be stored inside the umem so it can be used for these calculations. For now set it to umem->address by default and fix it up if ib_umem_find_best_pgsz() was called. This allows drivers to be converted to ib_umem_num_dma_blocks() safely. Link: https://lore.kernel.org/r/6-v2-270386b7e60b+28f4-umem_1_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'include/rdma')
-rw-r--r--include/rdma/ib_umem.h15
1 files changed, 12 insertions, 3 deletions
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index b880512ba95f..cf001d4e0a4f 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -17,6 +17,7 @@ struct ib_umem_odp;
struct ib_umem {
struct ib_device *ibdev;
struct mm_struct *owning_mm;
+ u64 iova;
size_t length;
unsigned long address;
u32 writable : 1;
@@ -33,11 +34,17 @@ static inline int ib_umem_offset(struct ib_umem *umem)
return umem->address & ~PAGE_MASK;
}
+static inline size_t ib_umem_num_dma_blocks(struct ib_umem *umem,
+ unsigned long pgsz)
+{
+ return (size_t)((ALIGN(umem->iova + umem->length, pgsz) -
+ ALIGN_DOWN(umem->iova, pgsz))) /
+ pgsz;
+}
+
static inline size_t ib_umem_num_pages(struct ib_umem *umem)
{
- return (ALIGN(umem->address + umem->length, PAGE_SIZE) -
- ALIGN_DOWN(umem->address, PAGE_SIZE)) >>
- PAGE_SHIFT;
+ return ib_umem_num_dma_blocks(umem, PAGE_SIZE);
}
static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
@@ -55,6 +62,8 @@ static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
* pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The
* returned DMA blocks will be aligned to pgsz and span the range:
* ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz)
+ *
+ * Performs exactly ib_umem_num_dma_blocks() iterations.
*/
#define rdma_umem_for_each_dma_block(umem, biter, pgsz) \
for (__rdma_umem_block_iter_start(biter, umem, pgsz); \