include/drm/drm_util.h

   1 /*
   2  * Internal Header for the Direct Rendering Manager
   3  *
   4  * Copyright 2018 Intel Corporation
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26 #ifndef _DRM_UTIL_H_
  27 #define _DRM_UTIL_H_
  28
  29 /**
  30  * DOC: drm utils
  31  *
  32  * Macros and inline functions that does not naturally belong in other places
  33  */
  34
  35 #include <linux/interrupt.h>
  36 #include <linux/kgdb.h>
  37 #include <linux/preempt.h>
  38 #include <linux/smp.h>
  39
  40 /*
  41  * Use EXPORT_SYMBOL_FOR_TESTS_ONLY() for functions that shall
  42  * only be visible for drmselftests.
  43  */
  44 #if defined(CONFIG_DRM_EXPORT_FOR_TESTS)
  45 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x) EXPORT_SYMBOL(x)
  46 #else
  47 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x)
  48 #endif
  49
  50 /**
  51  * for_each_if - helper for handling conditionals in various for_each macros
  52  * @condition: The condition to check
  53  *
  54  * Typical use::
  55  *
  56  *      #define for_each_foo_bar(x, y) \'
  57  *              list_for_each_entry(x, y->list, head) \'
  58  *                      for_each_if(x->something == SOMETHING)
  59  *
  60  * The for_each_if() macro makes the use of for_each_foo_bar() less error
  61  * prone.
  62  */
  63 #define for_each_if(condition) if (!(condition)) {} else
  64
  65 /**
  66  * drm_can_sleep - returns true if currently okay to sleep
  67  *
  68  * This function shall not be used in new code.
  69  * The check for running in atomic context may not work - see linux/preempt.h.
  70  *
  71  * FIXME: All users of drm_can_sleep should be removed (see todo.rst)
  72  *
  73  * Returns:
  74  * False if kgdb is active, we are in atomic context or irqs are disabled.
  75  */
  76 static inline bool drm_can_sleep(void)
  77 {
  78         if (in_atomic() || in_dbg_master() || irqs_disabled())
  79                 return false;
  80         return true;
  81 }
  82
  83 #endif