RDMA/rxe: Cleanup page variables in rxe_mr.c

Cleanup usage of mr->page_shift and mr->page_mask and introduce
an extractor for mr->ibmr.page_size. Normal usage in the kernel
has page_mask masking out offset in page rather than masking out
the page number. The rxe driver had reversed that which was confusing.
Implicitly there can be a per mr page_size which was not uniformly
supported.

Link: https://lore.kernel.org/r/20230119235936.19728-6-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/sw/rxe/rxe_mr.c b/drivers/infiniband/sw/rxe/rxe_mr.c
index 5c4ce43..2181165 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_mr.c
+++ b/drivers/infiniband/sw/rxe/rxe_mr.c
@@ -62,6 +62,9 @@ static void rxe_mr_init(int access, struct rxe_mr *mr)
        mr->lkey = mr->ibmr.lkey = lkey;
        mr->rkey = mr->ibmr.rkey = rkey;
 
+       mr->ibmr.page_size = PAGE_SIZE;
+       mr->page_mask = PAGE_MASK;
+       mr->page_shift = PAGE_SHIFT;
        mr->state = RXE_MR_STATE_INVALID;
 }
 
@@ -151,9 +154,6 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
                goto err_release_umem;
        }
 
-       mr->page_shift = PAGE_SHIFT;
-       mr->page_mask = PAGE_SIZE - 1;
-
        num_buf                 = 0;
        map = mr->map;
        if (length > 0) {
@@ -182,7 +182,7 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
                                goto err_release_umem;
                        }
                        buf->addr = (uintptr_t)vaddr;
-                       buf->size = PAGE_SIZE;
+                       buf->size = mr_page_size(mr);
                        num_buf++;
                        buf++;
 
@@ -191,10 +191,9 @@ int rxe_mr_init_user(struct rxe_dev *rxe, u64 start, u64 length, u64 iova,
 
        mr->umem = umem;
        mr->access = access;
-       mr->offset = ib_umem_offset(umem);
+       mr->page_offset = ib_umem_offset(umem);
        mr->state = RXE_MR_STATE_VALID;
        mr->ibmr.type = IB_MR_TYPE_USER;
-       mr->ibmr.page_size = PAGE_SIZE;
 
        return 0;
 
@@ -248,29 +247,27 @@ int rxe_map_mr_sg(struct ib_mr *ibmr, struct scatterlist *sg,
                  int sg_nents, unsigned int *sg_offset)
 {
        struct rxe_mr *mr = to_rmr(ibmr);
-       int n;
-
-       mr->nbuf = 0;
+       unsigned int page_size = mr_page_size(mr);
 
-       n = ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, rxe_set_page);
+       mr->page_shift = ilog2(page_size);
+       mr->page_mask = ~((u64)page_size - 1);
+       mr->page_offset = ibmr->iova & (page_size - 1);
 
-       mr->page_shift = ilog2(ibmr->page_size);
-       mr->page_mask = ibmr->page_size - 1;
-       mr->offset = ibmr->iova & mr->page_mask;
+       mr->nbuf = 0;
 
-       return n;
+       return ib_sg_to_pages(ibmr, sg, sg_nents, sg_offset, rxe_set_page);
 }
 
 static void lookup_iova(struct rxe_mr *mr, u64 iova, int *m_out, int *n_out,
                        size_t *offset_out)
 {
-       size_t offset = iova - mr->ibmr.iova + mr->offset;
+       size_t offset = iova - mr->ibmr.iova + mr->page_offset;
        int                     map_index;
        int                     buf_index;
        u64                     length;
 
        if (likely(mr->page_shift)) {
-               *offset_out = offset & mr->page_mask;
+               *offset_out = offset & (mr_page_size(mr) - 1);
                offset >>= mr->page_shift;
                *n_out = offset & mr->map_mask;
                *m_out = offset >> mr->map_shift;
@@ -329,7 +326,7 @@ int rxe_flush_pmem_iova(struct rxe_mr *mr, u64 iova, int length)
        if (mr->ibmr.type == IB_MR_TYPE_DMA)
                return -EFAULT;
 
-       offset = (iova - mr->ibmr.iova + mr->offset) & mr->page_mask;
+       offset = (iova - mr->ibmr.iova + mr->page_offset) & mr->page_mask;
        while (length > 0) {
                u8 *va;
                int bytes;

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.h b/drivers/infiniband/sw/rxe/rxe_verbs.h
index 19ddfa8..bfc94ca 100644 (file)
--- a/drivers/infiniband/sw/rxe/rxe_verbs.h
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.h
@@ -310,11 +310,11 @@ struct rxe_mr {
        u32                     lkey;
        u32                     rkey;
        enum rxe_mr_state       state;
-       u32                     offset;
        int                     access;
 
-       int                     page_shift;
-       int                     page_mask;
+       unsigned int            page_offset;
+       unsigned int            page_shift;
+       u64                     page_mask;
        int                     map_shift;
        int                     map_mask;
 
@@ -329,6 +329,11 @@ struct rxe_mr {
        struct rxe_map          **map;
 };
 
+static inline unsigned int mr_page_size(struct rxe_mr *mr)
+{
+       return mr ? mr->ibmr.page_size : PAGE_SIZE;
+}
+
 enum rxe_mw_state {
        RXE_MW_STATE_INVALID    = RXE_MR_STATE_INVALID,
        RXE_MW_STATE_FREE       = RXE_MR_STATE_FREE,