include/drm/drm_util.h

0001 /*
0002  * Internal Header for the Direct Rendering Manager
0003  *
0004  * Copyright 2018 Intel Corporation
0005  *
0006  * Permission is hereby granted, free of charge, to any person obtaining a
0007  * copy of this software and associated documentation files (the "Software"),
0008  * to deal in the Software without restriction, including without limitation
0009  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
0010  * and/or sell copies of the Software, and to permit persons to whom the
0011  * Software is furnished to do so, subject to the following conditions:
0012  *
0013  * The above copyright notice and this permission notice (including the next
0014  * paragraph) shall be included in all copies or substantial portions of the
0015  * Software.
0016  *
0017  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
0018  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
0019  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
0020  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
0021  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
0022  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
0023  * OTHER DEALINGS IN THE SOFTWARE.
0024  */
0025
0026 #ifndef _DRM_UTIL_H_
0027 #define _DRM_UTIL_H_
0028
0029 /**
0030  * DOC: drm utils
0031  *
0032  * Macros and inline functions that does not naturally belong in other places
0033  */
0034
0035 #include <linux/interrupt.h>
0036 #include <linux/kgdb.h>
0037 #include <linux/preempt.h>
0038 #include <linux/smp.h>
0039
0040 /*
0041  * Use EXPORT_SYMBOL_FOR_TESTS_ONLY() for functions that shall
0042  * only be visible for drmselftests.
0043  */
0044 #if defined(CONFIG_DRM_EXPORT_FOR_TESTS)
0045 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x) EXPORT_SYMBOL(x)
0046 #else
0047 #define EXPORT_SYMBOL_FOR_TESTS_ONLY(x)
0048 #endif
0049
0050 /**
0051  * for_each_if - helper for handling conditionals in various for_each macros
0052  * @condition: The condition to check
0053  *
0054  * Typical use::
0055  *
0056  *  #define for_each_foo_bar(x, y) \'
0057  *      list_for_each_entry(x, y->list, head) \'
0058  *          for_each_if(x->something == SOMETHING)
0059  *
0060  * The for_each_if() macro makes the use of for_each_foo_bar() less error
0061  * prone.
0062  */
0063 #define for_each_if(condition) if (!(condition)) {} else
0064
0065 /**
0066  * drm_can_sleep - returns true if currently okay to sleep
0067  *
0068  * This function shall not be used in new code.
0069  * The check for running in atomic context may not work - see linux/preempt.h.
0070  *
0071  * FIXME: All users of drm_can_sleep should be removed (see todo.rst)
0072  *
0073  * Returns:
0074  * False if kgdb is active, we are in atomic context or irqs are disabled.
0075  */
0076 static inline bool drm_can_sleep(void)
0077 {
0078     if (in_atomic() || in_dbg_master() || irqs_disabled())
0079         return false;
0080     return true;
0081 }
0082
0083 #endif