Clean up the LITMUS color device.

1 files changed, 125 insertions, 104 deletions

diff --git a/litmus/color_dev.c b/litmus/color_dev.c
index 51760328418e..677905a2a6b1 100644
--- a/litmus/color_dev.c
+++ b/litmus/color_dev.c
@@ -15,16 +15,49 @@
 
 extern unsigned long nr_colors;
 
+/************************************************************
+ * Common functions.
+************************************************************/
+
+static int mmap_common_checks(struct vm_area_struct *vma)
+{
+        /* you can only map the "first" page */
+        if (vma->vm_pgoff != 0)
+                return -EINVAL;
+
+        /* you can't share it with anyone */
+        if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED)) {
+                TRACE_CUR("error: page had MAYSHARE or SHARED set\n");
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static void mmap_common_vma_flags(struct vm_area_struct *vma)
+{
+        /* This mapping should not be kept across forks,
+         * cannot be expanded, and is not a "normal" page. */
+        vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_IO;
+
+        /* We don't want the first write access to trigger a "minor" page fault
+         * to mark the page as dirty.  This is transient, private memory, we
+         * don't care if it was touched or not. __S011 means RW access, but not
+         * execute, and avoids copy-on-write behavior.
+         * See protection_map in mmap.c.  */
+        vma->vm_page_prot = __S011;
+}
+
 /***********************************************************
  * Control device
 ***********************************************************/
 
 static void litmus_color_ctrl_vm_close(struct vm_area_struct *vma)
 {
-        TRACE_CUR("%s flags=0x%lx prot=0x%lx\n", __FUNCTION__,
+        TRACE_CUR("flags=0x%lx prot=0x%lx\n",
                         vma->vm_flags, pgprot_val(vma->vm_page_prot));
 
-        TRACE_CUR(CTRL_NAME ": %p:%p vma:%p vma->vm_private_data:%p closed.\n",
+        TRACE_CUR("%p:%p vma:%p vma->vm_private_data:%p closed.\n",
                         (void*) vma->vm_start, (void*) vma->vm_end, vma,
                         vma->vm_private_data);
 }
@@ -35,11 +68,10 @@ static int litmus_color_ctrl_vm_fault(struct vm_area_struct *vma,
         /* This function should never be called, since
          * all pages should have been mapped by mmap()
          * already. */
-        TRACE_CUR("%s flags=0x%lx\n", __FUNCTION__, vma->vm_flags);
-        printk(KERN_WARNING "fault: %s flags=0x%lx\n", __FUNCTION__,
-                        vma->vm_flags);
+        TRACE_CUR("flags=0x%lx (off:%ld)\n", vma->vm_flags, vmf->pgoff);
+
+        WARN(1, "Page fault in color ctrl page! flags=0x%lx\n", vma->vm_flags);
 
-        /* nope, you only get one page */
         return VM_FAULT_SIGBUS;
 }
 
@@ -48,63 +80,41 @@ static struct vm_operations_struct litmus_color_ctrl_vm_ops = {
         .fault  = litmus_color_ctrl_vm_fault,
 };
 
-static int mmap_common_checks(struct vm_area_struct *vma)
-{
-        /* you can only map the "first" page */
-        if (vma->vm_pgoff != 0)
-                return -EINVAL;
-
-#if 0
-        /* you can't share it with anyone */
-        /* well, maybe you can... */
-        if (vma->vm_flags & (VM_MAYSHARE | VM_SHARED))
-                return -EINVAL;
-#endif
-
-        return 0;
-}
-
 static int alloc_color_ctrl_page(void)
 {
-        struct task_struct *t;
+        struct task_struct *t = current;
         int err = 0;
 
-        t = current;
         /* only allocate if the task doesn't have one yet */
         if (!tsk_rt(t)->color_ctrl_page) {
                 tsk_rt(t)->color_ctrl_page = (void*) get_zeroed_page(GFP_KERNEL);
-                if (!tsk_rt(t)->color_ctrl_page)
+                if (!tsk_rt(t)->color_ctrl_page) {
+                        TRACE_TASK(t, "could not allocate control page\n");
                         err = -ENOMEM;
+                        goto out;
+                }
                 /* will get de-allocated in task teardown */
-                TRACE_TASK(t, "%s color_ctrl_page = %p\n", __FUNCTION__,
+                TRACE_TASK(t, "color_ctrl_page = %p\n",
                            tsk_rt(t)->color_ctrl_page);
         }
+out:
         return err;
 }
 
 static int map_color_ctrl_page(struct vm_area_struct *vma)
 {
-        int err;
-        unsigned long pfn;
+        int err = 0;
         struct task_struct *t = current;
         struct page *color_ctrl = virt_to_page(tsk_rt(t)->color_ctrl_page);
 
-        t = current;
-        /* Increase ref count. Is decreased when vma is destroyed. */
-        get_page(color_ctrl);
-        pfn = page_to_pfn(color_ctrl);
-
-        TRACE_CUR(CTRL_NAME
-                  ": mapping %p (pfn:%lx, %lx) to 0x%lx (flags:%lx prot:%lx)\n",
-                  tsk_rt(t)->color_ctrl_page, pfn, page_to_pfn(color_ctrl),
+        TRACE_CUR("mapping %p (pfn:%lx) to 0x%lx (flags:%lx prot:%lx)\n",
+                  tsk_rt(t)->color_ctrl_page, page_to_pfn(color_ctrl),
                   vma->vm_start, vma->vm_flags, pgprot_val(vma->vm_page_prot));
 
-        /* Map it into the vma. Make sure to use PAGE_SHARED, otherwise
-         * userspace actually gets a copy-on-write page. */
-        err = remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE, PAGE_SHARED);
-
+        /* Map it into the vma. */
+        err = vm_insert_page(vma, vma->vm_start, color_ctrl);
         if (err)
-                TRACE_CUR(CTRL_NAME ": remap_pfn_range() failed (%d)\n", err);
+                TRACE_CUR("vm_insert_page() failed (%d)\n", err);
 
         return err;
 }
@@ -115,27 +125,25 @@ static int litmus_color_ctrl_mmap(struct file *filp, struct vm_area_struct *vma)
 
         /* you can only get one page */
         if (vma->vm_end - vma->vm_start != PAGE_SIZE) {
-                TRACE_CUR(CTRL_NAME ": must allocate a multiple of PAGE_SIZE\n");
+                TRACE_CUR("must allocate a multiple of PAGE_SIZE\n");
                 err = -EINVAL;
                 goto out;
         }
 
         err = mmap_common_checks(vma);
         if (err) {
-                TRACE_CUR(CTRL_NAME ": failed common mmap checks.\n");
+                TRACE_CUR("failed common mmap checks.\n");
                 goto out;
         }
 
         vma->vm_ops = &litmus_color_ctrl_vm_ops;
-        /* this mapping should not be kept across forks,
-         * and cannot be expanded */
-        vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND;
+        mmap_common_vma_flags(vma);
 
         err = alloc_color_ctrl_page();
         if (!err)
                 err = map_color_ctrl_page(vma);
 
-        TRACE_CUR("%s flags=0x%lx prot=0x%lx\n", __FUNCTION__, vma->vm_flags,
+        TRACE_CUR("flags=0x%lx prot=0x%lx\n", vma->vm_flags,
                         pgprot_val(vma->vm_page_prot));
 out:
         return err;
@@ -149,6 +157,51 @@ out:
 #define vma_nr_pages(vma) \
         ({unsigned long v = ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT); v;})
 
+static int do_map_colored_page_set(struct vm_area_struct *vma,
+                const unsigned long starting_at,
+                const unsigned long color_no,
+                const int nr_pages)
+{
+        int i, err = 0;
+
+        for (i = 0; i < nr_pages; ++i) {
+                const unsigned long addr = starting_at + (i << PAGE_SHIFT);
+                struct page *page = get_colored_page(color_no);
+
+                if (!page) {
+                        TRACE_CUR("Could not get page with color %lu.\n",
+                                        color_no);
+                        /* TODO unmap mapped pages? */
+                        err = -ENOMEM;
+                        goto out;
+                }
+
+#ifdef CONFIG_SPARC
+                clear_user_highpage(page, addr);
+#endif
+
+                TRACE_CUR("insert page (pa:0x%10llx, pfn:%8lu, color:%3lu) "
+                                "at 0x%lx vma:(flags:%16lx prot:%16lx)\n",
+                                page_to_phys(page),
+                                page_to_pfn(page),
+                                color_no,
+                                addr,
+                                vma->vm_flags,
+                                pgprot_val(vma->vm_page_prot));
+
+                err = vm_insert_page(vma, addr, page);
+                if (err) {
+                        TRACE_CUR("vm_insert_page() failed (%d)\n", err);
+                        /* TODO unmap mapped pages? */
+                        err = -EINVAL;
+                        goto out;
+                }
+                add_page_to_alloced_list(page, vma);
+        }
+out:
+        return err;
+}
+
 static int do_map_colored_pages(struct vm_area_struct *vma)
 {
         const unsigned long nr_pages = vma_nr_pages(vma);
@@ -156,67 +209,36 @@ static int do_map_colored_pages(struct vm_area_struct *vma)
         unsigned long nr_mapped;
         int i, err = 0;
 
-        TRACE_CUR(ALLOC_NAME ": allocating %lu pages (flags:%lx prot:%lx)\n",
+        TRACE_CUR("allocating %lu pages (flags:%lx prot:%lx)\n",
                         nr_pages, vma->vm_flags, pgprot_val(vma->vm_page_prot));
 
 #ifdef CONFIG_PLUGIN_COLOR_UNCACHABLE
+        /* Adds non-cached on x86 */
         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 #endif
 
         for (i = 0, nr_mapped = 0; nr_mapped < nr_pages; ++i) {
                 const unsigned long color_no = color_ctrl->colors[i];
-                unsigned int page_no = 0;
+                const unsigned long color_quantity = color_ctrl->pages[i];
+                const unsigned long addr = vma->vm_start +
+                        (nr_mapped << PAGE_SHIFT);
 
-                for (; page_no < color_ctrl->pages[i]; ++page_no, ++nr_mapped) {
-                        const unsigned long addr = vma->vm_start +
-                                (nr_mapped << PAGE_SHIFT);
-                        struct page *page = get_colored_page(color_no);
-#ifdef CONFIG_PLUGIN_COLOR_UNCACHABLE
-                        const pgprot_t ins_prot = pgprot_noncached(PAGE_SHARED);
-#else
-                        const pgprot_t ins_prot = PAGE_SHARED;
-#endif
-
-                        if (!page) {
-                                TRACE_CUR(ALLOC_NAME ": Could not get page with"
-                                          " color %lu.\n", color_no);
-                                /* TODO unmap mapped pages */
-                                err = -ENOMEM;
-                                goto out;
-                        }
-
-#ifdef CONFIG_SPARC
-                        clear_user_highpage(page, addr);
-#endif
-
-                        TRACE_CUR(ALLOC_NAME ": insert page (pa:0x%10llx, "
-                                  "pfn:%8lu, color:%3lu, prot:%lx) at 0x%lx "
-                                  "vma:(flags:%16lx prot:%16lx)\n",
-                                  page_to_phys(page),
-                                  page_to_pfn(page), color_no,
-                                  pgprot_val(ins_prot), addr,
-                                  vma->vm_flags,
-                                  pgprot_val(vma->vm_page_prot));
-
-                        err = remap_pfn_range(vma, addr, page_to_pfn(page),
-                                        PAGE_SIZE, ins_prot);
-                        if (err) {
-                                TRACE_CUR(ALLOC_NAME ": remap_pfn_range() fail "
-                                          "(%d)\n", err);
-                                /* TODO unmap mapped pages */
-                                err = -EINVAL;
-                                goto out;
-                        }
-                        add_page_to_alloced_list(page, vma);
+                if (!nr_pages) {
+                        TRACE_CUR("0 pages given for color %lu\n", color_no);
+                        err = -EINVAL;
+                        goto out;
                 }
 
-                if (!page_no) {
-                        TRACE_CUR(ALLOC_NAME ": 0 pages given for color %lu\n",
-                                  color_no);
+                err = do_map_colored_page_set(vma, addr,
+                                color_no, color_quantity);
+                if (err) {
+                        TRACE_CUR("Could not map colored page set.\n");
                         err = -EINVAL;
                         goto out;
                 }
+                nr_mapped += color_quantity;
         }
+        TRACE_CUR("Successfully mapped %lu pages.\n", nr_mapped);
  out:
         return err;
 }
@@ -244,10 +266,10 @@ out:
 
 static void litmus_color_alloc_vm_close(struct vm_area_struct *vma)
 {
-        TRACE_CUR("%s flags=0x%lx prot=0x%lx\n", __FUNCTION__,
+        TRACE_CUR("flags=0x%lx prot=0x%lx\n",
                         vma->vm_flags, pgprot_val(vma->vm_page_prot));
 
-        TRACE_CUR(ALLOC_NAME ": %p:%p vma:%p vma->vm_private_data:%p closed.\n",
+        TRACE_CUR("%p:%p vma:%p vma->vm_private_data:%p closed.\n",
                         (void*) vma->vm_start, (void*) vma->vm_end, vma,
                         vma->vm_private_data);
         reclaim_pages(vma);
@@ -259,11 +281,10 @@ static int litmus_color_alloc_vm_fault(struct vm_area_struct *vma,
         /* This function should never be called, since
          * all pages should have been mapped by mmap()
          * already. */
-        TRACE_CUR("%s flags=0x%lx\n", __FUNCTION__, vma->vm_flags);
-        printk(KERN_WARNING "fault: %s flags=0x%lx\n", __FUNCTION__,
-                        vma->vm_flags);
+        TRACE_CUR("flags=0x%lx (off:%ld)\n", vma->vm_flags, vmf->pgoff);
+
+        WARN(1, "Page fault in color ctrl page! flags=0x%lx\n", vma->vm_flags);
 
-        /* nope, you only get one page */
         return VM_FAULT_SIGBUS;
 }
 
@@ -283,17 +304,17 @@ static int litmus_color_alloc_mmap(struct file *filp, struct vm_area_struct *vma
         }
 
         err = mmap_common_checks(vma);
-        if (err)
+        if (err) {
+                TRACE_CUR("failed mmap common checks\n");
                 goto out;
+        }
 
         vma->vm_ops = &litmus_color_alloc_vm_ops;
-        /* this mapping should not be kept across forks,
-         * and cannot be expanded */
-        vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND;
+        mmap_common_vma_flags(vma);
 
         err = map_colored_pages(vma);
 
-        TRACE_CUR("%s flags=0x%lx prot=0x%lx\n", __FUNCTION__, vma->vm_flags,
+        TRACE_CUR("flags=0x%lx prot=0x%lx\n", vma->vm_flags,
                         pgprot_val(vma->vm_page_prot));
 out:
         return err;