VMCI: handle array implementation.

VMCI handle code adds support for dynamic arrays that will grow if they need to.

Signed-off-by: George Zhang <georgezhang@vmware.com>
Acked-by: Andy king <acking@vmware.com>
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 194 insertions, 0 deletions

diff --git a/drivers/misc/vmw_vmci/vmci_handle_array.c b/drivers/misc/vmw_vmci/vmci_handle_array.c
new file mode 100644
index 000000000000..344973a0fb0a
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_handle_array.c
@@ -0,0 +1,142 @@
+/*
+ * VMware VMCI Driver
+ *
+ * Copyright (C) 2012 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation version 2 and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include <linux/slab.h>
+#include "vmci_handle_array.h"
+
+static size_t handle_arr_calc_size(size_t capacity)
+{
+        return sizeof(struct vmci_handle_arr) +
+            capacity * sizeof(struct vmci_handle);
+}
+
+struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity)
+{
+        struct vmci_handle_arr *array;
+
+        if (capacity == 0)
+                capacity = VMCI_HANDLE_ARRAY_DEFAULT_SIZE;
+
+        array = kmalloc(handle_arr_calc_size(capacity), GFP_ATOMIC);
+        if (!array)
+                return NULL;
+
+        array->capacity = capacity;
+        array->size = 0;
+
+        return array;
+}
+
+void vmci_handle_arr_destroy(struct vmci_handle_arr *array)
+{
+        kfree(array);
+}
+
+void vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
+                                  struct vmci_handle handle)
+{
+        struct vmci_handle_arr *array = *array_ptr;
+
+        if (unlikely(array->size >= array->capacity)) {
+                /* reallocate. */
+                struct vmci_handle_arr *new_array;
+                size_t new_capacity = array->capacity * VMCI_ARR_CAP_MULT;
+                size_t new_size = handle_arr_calc_size(new_capacity);
+
+                new_array = krealloc(array, new_size, GFP_ATOMIC);
+                if (!new_array)
+                        return;
+
+                new_array->capacity = new_capacity;
+                *array_ptr = array = new_array;
+        }
+
+        array->entries[array->size] = handle;
+        array->size++;
+}
+
+/*
+ * Handle that was removed, VMCI_INVALID_HANDLE if entry not found.
+ */
+struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
+                                                struct vmci_handle entry_handle)
+{
+        struct vmci_handle handle = VMCI_INVALID_HANDLE;
+        size_t i;
+
+        for (i = 0; i < array->size; i++) {
+                if (vmci_handle_is_equal(array->entries[i], entry_handle)) {
+                        handle = array->entries[i];
+                        array->size--;
+                        array->entries[i] = array->entries[array->size];
+                        array->entries[array->size] = VMCI_INVALID_HANDLE;
+                        break;
+                }
+        }
+
+        return handle;
+}
+
+/*
+ * Handle that was removed, VMCI_INVALID_HANDLE if array was empty.
+ */
+struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array)
+{
+        struct vmci_handle handle = VMCI_INVALID_HANDLE;
+
+        if (array->size) {
+                array->size--;
+                handle = array->entries[array->size];
+                array->entries[array->size] = VMCI_INVALID_HANDLE;
+        }
+
+        return handle;
+}
+
+/*
+ * Handle at given index, VMCI_INVALID_HANDLE if invalid index.
+ */
+struct vmci_handle
+vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index)
+{
+        if (unlikely(index >= array->size))
+                return VMCI_INVALID_HANDLE;
+
+        return array->entries[index];
+}
+
+bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
+                               struct vmci_handle entry_handle)
+{
+        size_t i;
+
+        for (i = 0; i < array->size; i++)
+                if (vmci_handle_is_equal(array->entries[i], entry_handle))
+                        return true;
+
+        return false;
+}
+
+/*
+ * NULL if the array is empty. Otherwise, a pointer to the array
+ * of VMCI handles in the handle array.
+ */
+struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array)
+{
+        if (array->size)
+                return array->entries;
+
+        return NULL;
+}
diff --git a/drivers/misc/vmw_vmci/vmci_handle_array.h b/drivers/misc/vmw_vmci/vmci_handle_array.h
new file mode 100644
index 000000000000..b5f3a7f98cf1
--- /dev/null
+++ b/drivers/misc/vmw_vmci/vmci_handle_array.h
@@ -0,0 +1,52 @@
+/*
+ * VMware VMCI Driver
+ *
+ * Copyright (C) 2012 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation version 2 and no later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#ifndef _VMCI_HANDLE_ARRAY_H_
+#define _VMCI_HANDLE_ARRAY_H_
+
+#include <linux/vmw_vmci_defs.h>
+#include <linux/types.h>
+
+#define VMCI_HANDLE_ARRAY_DEFAULT_SIZE 4
+#define VMCI_ARR_CAP_MULT 2     /* Array capacity multiplier */
+
+struct vmci_handle_arr {
+        size_t capacity;
+        size_t size;
+        struct vmci_handle entries[];
+};
+
+struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity);
+void vmci_handle_arr_destroy(struct vmci_handle_arr *array);
+void vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
+                                  struct vmci_handle handle);
+struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
+                                                struct vmci_handle
+                                                entry_handle);
+struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array);
+struct vmci_handle
+vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index);
+bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
+                               struct vmci_handle entry_handle);
+struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array);
+
+static inline size_t vmci_handle_arr_get_size(
+        const struct vmci_handle_arr *array)
+{
+        return array->size;
+}
+
+
+#endif /* _VMCI_HANDLE_ARRAY_H_ */