Merge branch 'fixes-for-v3.18' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping

Pull CMA and DMA-mapping fixes from Marek Szyprowski:
 "This contains important fixes for recently introduced highmem support
  for default contiguous memory region used for dma-mapping subsystem"

* 'fixes-for-v3.18' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
  mm, cma: make parameters order consistent in func declaration and definition
  mm: cma: Use %pa to print physical addresses
  mm: cma: Ensure that reservations never cross the low/high mem boundary
  mm: cma: Always consider a 0 base address reservation as dynamic
  mm: cma: Don't crash on allocation if CMA area can't be activated

1 files changed, 44 insertions, 24 deletions

diff --git a/mm/cma.c b/mm/cma.c
index 963bc4add9af..fde706e1284f 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -124,6 +124,7 @@ static int __init cma_activate_area(struct cma *cma)
 
 err:
         kfree(cma->bitmap);
+        cma->count = 0;
         return -EINVAL;
 }
 
@@ -217,9 +218,8 @@ int __init cma_declare_contiguous(phys_addr_t base,
         phys_addr_t highmem_start = __pa(high_memory);
         int ret = 0;
 
-        pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
-                __func__, (unsigned long)size, (unsigned long)base,
-                (unsigned long)limit, (unsigned long)alignment);
+        pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
+                __func__, &size, &base, &limit, &alignment);
 
         if (cma_area_count == ARRAY_SIZE(cma_areas)) {
                 pr_err("Not enough slots for CMA reserved regions!\n");
@@ -244,52 +244,72 @@ int __init cma_declare_contiguous(phys_addr_t base,
         size = ALIGN(size, alignment);
         limit &= ~(alignment - 1);
 
+        if (!base)
+                fixed = false;
+
         /* size should be aligned with order_per_bit */
         if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
                 return -EINVAL;
 
         /*
-         * adjust limit to avoid crossing low/high memory boundary for
-         * automatically allocated regions
+         * If allocating at a fixed base the request region must not cross the
+         * low/high memory boundary.
          */
-        if (((limit == 0 || limit > memblock_end) &&
-             (memblock_end - size < highmem_start &&
-              memblock_end > highmem_start)) ||
-            (!fixed && limit > highmem_start && limit - size < highmem_start)) {
-                limit = highmem_start;
-        }
-
-        if (fixed && base < highmem_start && base+size > highmem_start) {
+        if (fixed && base < highmem_start && base + size > highmem_start) {
                 ret = -EINVAL;
-                pr_err("Region at %08lx defined on low/high memory boundary (%08lx)\n",
-                        (unsigned long)base, (unsigned long)highmem_start);
+                pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
+                        &base, &highmem_start);
                 goto err;
         }
 
+        /*
+         * If the limit is unspecified or above the memblock end, its effective
+         * value will be the memblock end. Set it explicitly to simplify further
+         * checks.
+         */
+        if (limit == 0 || limit > memblock_end)
+                limit = memblock_end;
+
         /* Reserve memory */
-        if (base && fixed) {
+        if (fixed) {
                 if (memblock_is_region_reserved(base, size) ||
                     memblock_reserve(base, size) < 0) {
                         ret = -EBUSY;
                         goto err;
                 }
         } else {
-                phys_addr_t addr = memblock_alloc_range(size, alignment, base,
-                                                        limit);
+                phys_addr_t addr = 0;
+
+                /*
+                 * All pages in the reserved area must come from the same zone.
+                 * If the requested region crosses the low/high memory boundary,
+                 * try allocating from high memory first and fall back to low
+                 * memory in case of failure.
+                 */
+                if (base < highmem_start && limit > highmem_start) {
+                        addr = memblock_alloc_range(size, alignment,
+                                                    highmem_start, limit);
+                        limit = highmem_start;
+                }
+
                 if (!addr) {
-                        ret = -ENOMEM;
-                        goto err;
-                } else {
-                        base = addr;
+                        addr = memblock_alloc_range(size, alignment, base,
+                                                    limit);
+                        if (!addr) {
+                                ret = -ENOMEM;
+                                goto err;
+                        }
                 }
+
+                base = addr;
         }
 
         ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
         if (ret)
                 goto err;
 
-        pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
-                (unsigned long)base);
+        pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
+                &base);
         return 0;
 
 err: