Merge branch 'dynamic_sg' into rdma.git for-next

[linux-2.6-microblaze.git] / drivers / infiniband / core / umem.c

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 52c55e9..e9fecbd 100644 (file)
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -39,6 +39,7 @@
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include <linux/count_zeros.h>
 #include <rdma/ib_umem_odp.h>
 
 #include "uverbs.h"
@@ -79,18 +80,28 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
                                     unsigned long virt)
 {
        struct scatterlist *sg;
-       unsigned int best_pg_bit;
        unsigned long va, pgoff;
        dma_addr_t mask;
        int i;
 
+       /* rdma_for_each_block() has a bug if the page size is smaller than the
+        * page size used to build the umem. For now prevent smaller page sizes
+        * from being returned.
+        */
+       pgsz_bitmap &= GENMASK(BITS_PER_LONG - 1, PAGE_SHIFT);
+
        /* At minimum, drivers must support PAGE_SIZE or smaller */
        if (WARN_ON(!(pgsz_bitmap & GENMASK(PAGE_SHIFT, 0))))
                return 0;
 
-       va = virt;
-       /* max page size not to exceed MR length */
-       mask = roundup_pow_of_two(umem->length);
+       umem->iova = va = virt;
+       /* The best result is the smallest page size that results in the minimum
+        * number of required pages. Compute the largest page size that could
+        * work based on VA address bits that don't change.
+        */
+       mask = pgsz_bitmap &
+              GENMASK(BITS_PER_LONG - 1,
+                      bits_per((umem->length - 1 + virt) ^ virt));
        /* offset into first SGL */
        pgoff = umem->address & ~PAGE_MASK;
 
@@ -108,9 +119,14 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem,
                        mask |= va;
                pgoff = 0;
        }
-       best_pg_bit = rdma_find_pg_bit(mask, pgsz_bitmap);
 
-       return BIT_ULL(best_pg_bit);
+       /* The mask accumulates 1's in each position where the VA and physical
+        * address differ, thus the length of trailing 0 is the largest page
+        * size that can pass the VA through to the physical.
+        */
+       if (mask)
+               pgsz_bitmap &= GENMASK(count_trailing_zeros(mask), 0);
+       return rounddown_pow_of_two(pgsz_bitmap);
 }
 EXPORT_SYMBOL(ib_umem_find_best_pgsz);
 
@@ -157,6 +173,11 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
        umem->ibdev      = device;
        umem->length     = size;
        umem->address    = addr;
+       /*
+        * Drivers should call ib_umem_find_best_pgsz() to set the iova
+        * correctly.
+        */
+       umem->iova = addr;
        umem->writable   = ib_access_writable(access);
        umem->owning_mm = mm = current->mm;
        mmgrab(mm);
@@ -259,18 +280,6 @@ void ib_umem_release(struct ib_umem *umem)
 }
 EXPORT_SYMBOL(ib_umem_release);
 
-int ib_umem_page_count(struct ib_umem *umem)
-{
-       int i, n = 0;
-       struct scatterlist *sg;
-
-       for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
-               n += sg_dma_len(sg) >> PAGE_SHIFT;
-
-       return n;
-}
-EXPORT_SYMBOL(ib_umem_page_count);
-
 /*
  * Copy from the given ib_umem's pages to the given buffer.
  *