cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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kfd_mqd_manager_v11.c (15404B)


      1/*
      2 * Copyright 2021 Advanced Micro Devices, Inc.
      3 *
      4 * Permission is hereby granted, free of charge, to any person obtaining a
      5 * copy of this software and associated documentation files (the "Software"),
      6 * to deal in the Software without restriction, including without limitation
      7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8 * and/or sell copies of the Software, and to permit persons to whom the
      9 * Software is furnished to do so, subject to the following conditions:
     10 *
     11 * The above copyright notice and this permission notice shall be included in
     12 * all copies or substantial portions of the Software.
     13 *
     14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
     18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     20 * OTHER DEALINGS IN THE SOFTWARE.
     21 *
     22 */
     23
     24#include <linux/printk.h>
     25#include <linux/slab.h>
     26#include <linux/uaccess.h>
     27#include "kfd_priv.h"
     28#include "kfd_mqd_manager.h"
     29#include "v11_structs.h"
     30#include "gc/gc_11_0_0_offset.h"
     31#include "gc/gc_11_0_0_sh_mask.h"
     32#include "amdgpu_amdkfd.h"
     33
     34static inline struct v11_compute_mqd *get_mqd(void *mqd)
     35{
     36	return (struct v11_compute_mqd *)mqd;
     37}
     38
     39static inline struct v11_sdma_mqd *get_sdma_mqd(void *mqd)
     40{
     41	return (struct v11_sdma_mqd *)mqd;
     42}
     43
     44static void update_cu_mask(struct mqd_manager *mm, void *mqd,
     45			   struct mqd_update_info *minfo)
     46{
     47	struct v11_compute_mqd *m;
     48	uint32_t se_mask[KFD_MAX_NUM_SE] = {0};
     49
     50	if (!minfo || (minfo->update_flag != UPDATE_FLAG_CU_MASK) ||
     51	    !minfo->cu_mask.ptr)
     52		return;
     53
     54	mqd_symmetrically_map_cu_mask(mm,
     55		minfo->cu_mask.ptr, minfo->cu_mask.count, se_mask);
     56
     57	m = get_mqd(mqd);
     58	m->compute_static_thread_mgmt_se0 = se_mask[0];
     59	m->compute_static_thread_mgmt_se1 = se_mask[1];
     60	m->compute_static_thread_mgmt_se2 = se_mask[2];
     61	m->compute_static_thread_mgmt_se3 = se_mask[3];
     62	m->compute_static_thread_mgmt_se4 = se_mask[4];
     63	m->compute_static_thread_mgmt_se5 = se_mask[5];
     64	m->compute_static_thread_mgmt_se6 = se_mask[6];
     65	m->compute_static_thread_mgmt_se7 = se_mask[7];
     66
     67	pr_debug("update cu mask to %#x %#x %#x %#x %#x %#x %#x %#x\n",
     68		m->compute_static_thread_mgmt_se0,
     69		m->compute_static_thread_mgmt_se1,
     70		m->compute_static_thread_mgmt_se2,
     71		m->compute_static_thread_mgmt_se3,
     72		m->compute_static_thread_mgmt_se4,
     73		m->compute_static_thread_mgmt_se5,
     74		m->compute_static_thread_mgmt_se6,
     75		m->compute_static_thread_mgmt_se7);
     76}
     77
     78static void set_priority(struct v11_compute_mqd *m, struct queue_properties *q)
     79{
     80	m->cp_hqd_pipe_priority = pipe_priority_map[q->priority];
     81	m->cp_hqd_queue_priority = q->priority;
     82}
     83
     84static struct kfd_mem_obj *allocate_mqd(struct kfd_dev *kfd,
     85		struct queue_properties *q)
     86{
     87	struct kfd_mem_obj *mqd_mem_obj;
     88	int size;
     89
     90	/*
     91	 * MES write to areas beyond MQD size. So allocate
     92	 * 1 PAGE_SIZE memory for MQD is MES is enabled.
     93	 */
     94	if (kfd->shared_resources.enable_mes)
     95		size = PAGE_SIZE;
     96	else
     97		size = sizeof(struct v11_compute_mqd);
     98
     99	if (kfd_gtt_sa_allocate(kfd, size, &mqd_mem_obj))
    100		return NULL;
    101
    102	return mqd_mem_obj;
    103}
    104
    105static void init_mqd(struct mqd_manager *mm, void **mqd,
    106			struct kfd_mem_obj *mqd_mem_obj, uint64_t *gart_addr,
    107			struct queue_properties *q)
    108{
    109	uint64_t addr;
    110	struct v11_compute_mqd *m;
    111	int size;
    112
    113	m = (struct v11_compute_mqd *) mqd_mem_obj->cpu_ptr;
    114	addr = mqd_mem_obj->gpu_addr;
    115
    116	if (mm->dev->shared_resources.enable_mes)
    117		size = PAGE_SIZE;
    118	else
    119		size = sizeof(struct v11_compute_mqd);
    120
    121	memset(m, 0, size);
    122
    123	m->header = 0xC0310800;
    124	m->compute_pipelinestat_enable = 1;
    125	m->compute_static_thread_mgmt_se0 = 0xFFFFFFFF;
    126	m->compute_static_thread_mgmt_se1 = 0xFFFFFFFF;
    127	m->compute_static_thread_mgmt_se2 = 0xFFFFFFFF;
    128	m->compute_static_thread_mgmt_se3 = 0xFFFFFFFF;
    129
    130	m->cp_hqd_persistent_state = CP_HQD_PERSISTENT_STATE__PRELOAD_REQ_MASK |
    131			0x55 << CP_HQD_PERSISTENT_STATE__PRELOAD_SIZE__SHIFT;
    132
    133	m->cp_mqd_control = 1 << CP_MQD_CONTROL__PRIV_STATE__SHIFT;
    134
    135	m->cp_mqd_base_addr_lo        = lower_32_bits(addr);
    136	m->cp_mqd_base_addr_hi        = upper_32_bits(addr);
    137
    138	m->cp_hqd_quantum = 1 << CP_HQD_QUANTUM__QUANTUM_EN__SHIFT |
    139			1 << CP_HQD_QUANTUM__QUANTUM_SCALE__SHIFT |
    140			1 << CP_HQD_QUANTUM__QUANTUM_DURATION__SHIFT;
    141
    142	if (q->format == KFD_QUEUE_FORMAT_AQL) {
    143		m->cp_hqd_aql_control =
    144			1 << CP_HQD_AQL_CONTROL__CONTROL0__SHIFT;
    145	}
    146
    147	if (mm->dev->cwsr_enabled) {
    148		m->cp_hqd_persistent_state |=
    149			(1 << CP_HQD_PERSISTENT_STATE__QSWITCH_MODE__SHIFT);
    150		m->cp_hqd_ctx_save_base_addr_lo =
    151			lower_32_bits(q->ctx_save_restore_area_address);
    152		m->cp_hqd_ctx_save_base_addr_hi =
    153			upper_32_bits(q->ctx_save_restore_area_address);
    154		m->cp_hqd_ctx_save_size = q->ctx_save_restore_area_size;
    155		m->cp_hqd_cntl_stack_size = q->ctl_stack_size;
    156		m->cp_hqd_cntl_stack_offset = q->ctl_stack_size;
    157		m->cp_hqd_wg_state_offset = q->ctl_stack_size;
    158	}
    159
    160	*mqd = m;
    161	if (gart_addr)
    162		*gart_addr = addr;
    163	mm->update_mqd(mm, m, q, NULL);
    164}
    165
    166static int load_mqd(struct mqd_manager *mm, void *mqd,
    167			uint32_t pipe_id, uint32_t queue_id,
    168			struct queue_properties *p, struct mm_struct *mms)
    169{
    170	int r = 0;
    171	/* AQL write pointer counts in 64B packets, PM4/CP counts in dwords. */
    172	uint32_t wptr_shift = (p->format == KFD_QUEUE_FORMAT_AQL ? 4 : 0);
    173
    174	r = mm->dev->kfd2kgd->hqd_load(mm->dev->adev, mqd, pipe_id, queue_id,
    175					  (uint32_t __user *)p->write_ptr,
    176					  wptr_shift, 0, mms);
    177	return r;
    178}
    179
    180static int hiq_load_mqd_kiq(struct mqd_manager *mm, void *mqd,
    181			    uint32_t pipe_id, uint32_t queue_id,
    182			    struct queue_properties *p, struct mm_struct *mms)
    183{
    184	return mm->dev->kfd2kgd->hiq_mqd_load(mm->dev->adev, mqd, pipe_id,
    185					      queue_id, p->doorbell_off);
    186}
    187
    188static void update_mqd(struct mqd_manager *mm, void *mqd,
    189		       struct queue_properties *q,
    190		       struct mqd_update_info *minfo)
    191{
    192	struct v11_compute_mqd *m;
    193
    194	m = get_mqd(mqd);
    195
    196	m->cp_hqd_pq_control = 5 << CP_HQD_PQ_CONTROL__RPTR_BLOCK_SIZE__SHIFT;
    197	m->cp_hqd_pq_control |=
    198			ffs(q->queue_size / sizeof(unsigned int)) - 1 - 1;
    199	pr_debug("cp_hqd_pq_control 0x%x\n", m->cp_hqd_pq_control);
    200
    201	m->cp_hqd_pq_base_lo = lower_32_bits((uint64_t)q->queue_address >> 8);
    202	m->cp_hqd_pq_base_hi = upper_32_bits((uint64_t)q->queue_address >> 8);
    203
    204	m->cp_hqd_pq_rptr_report_addr_lo = lower_32_bits((uint64_t)q->read_ptr);
    205	m->cp_hqd_pq_rptr_report_addr_hi = upper_32_bits((uint64_t)q->read_ptr);
    206	m->cp_hqd_pq_wptr_poll_addr_lo = lower_32_bits((uint64_t)q->write_ptr);
    207	m->cp_hqd_pq_wptr_poll_addr_hi = upper_32_bits((uint64_t)q->write_ptr);
    208
    209	m->cp_hqd_pq_doorbell_control =
    210		q->doorbell_off <<
    211			CP_HQD_PQ_DOORBELL_CONTROL__DOORBELL_OFFSET__SHIFT;
    212	pr_debug("cp_hqd_pq_doorbell_control 0x%x\n",
    213			m->cp_hqd_pq_doorbell_control);
    214
    215	m->cp_hqd_ib_control = 3 << CP_HQD_IB_CONTROL__MIN_IB_AVAIL_SIZE__SHIFT;
    216
    217	/*
    218	 * HW does not clamp this field correctly. Maximum EOP queue size
    219	 * is constrained by per-SE EOP done signal count, which is 8-bit.
    220	 * Limit is 0xFF EOP entries (= 0x7F8 dwords). CP will not submit
    221	 * more than (EOP entry count - 1) so a queue size of 0x800 dwords
    222	 * is safe, giving a maximum field value of 0xA.
    223	 */
    224	m->cp_hqd_eop_control = min(0xA,
    225		ffs(q->eop_ring_buffer_size / sizeof(unsigned int)) - 1 - 1);
    226	m->cp_hqd_eop_base_addr_lo =
    227			lower_32_bits(q->eop_ring_buffer_address >> 8);
    228	m->cp_hqd_eop_base_addr_hi =
    229			upper_32_bits(q->eop_ring_buffer_address >> 8);
    230
    231	m->cp_hqd_iq_timer = 0;
    232
    233	m->cp_hqd_vmid = q->vmid;
    234
    235	if (q->format == KFD_QUEUE_FORMAT_AQL) {
    236		/* GC 10 removed WPP_CLAMP from PQ Control */
    237		m->cp_hqd_pq_control |= CP_HQD_PQ_CONTROL__NO_UPDATE_RPTR_MASK |
    238				2 << CP_HQD_PQ_CONTROL__SLOT_BASED_WPTR__SHIFT |
    239				1 << CP_HQD_PQ_CONTROL__QUEUE_FULL_EN__SHIFT ;
    240		m->cp_hqd_pq_doorbell_control |=
    241			1 << CP_HQD_PQ_DOORBELL_CONTROL__DOORBELL_BIF_DROP__SHIFT;
    242	}
    243	if (mm->dev->cwsr_enabled)
    244		m->cp_hqd_ctx_save_control = 0;
    245
    246	update_cu_mask(mm, mqd, minfo);
    247	set_priority(m, q);
    248
    249	q->is_active = QUEUE_IS_ACTIVE(*q);
    250}
    251
    252static uint32_t read_doorbell_id(void *mqd)
    253{
    254	struct v11_compute_mqd *m = (struct v11_compute_mqd *)mqd;
    255
    256	return m->queue_doorbell_id0;
    257}
    258
    259static int destroy_mqd(struct mqd_manager *mm, void *mqd,
    260		       enum kfd_preempt_type type,
    261		       unsigned int timeout, uint32_t pipe_id,
    262		       uint32_t queue_id)
    263{
    264	return mm->dev->kfd2kgd->hqd_destroy
    265		(mm->dev->adev, mqd, type, timeout,
    266		 pipe_id, queue_id);
    267}
    268
    269static void free_mqd(struct mqd_manager *mm, void *mqd,
    270			struct kfd_mem_obj *mqd_mem_obj)
    271{
    272	kfd_gtt_sa_free(mm->dev, mqd_mem_obj);
    273}
    274
    275static bool is_occupied(struct mqd_manager *mm, void *mqd,
    276			uint64_t queue_address,	uint32_t pipe_id,
    277			uint32_t queue_id)
    278{
    279	return mm->dev->kfd2kgd->hqd_is_occupied(
    280		mm->dev->adev, queue_address,
    281		pipe_id, queue_id);
    282}
    283
    284static int get_wave_state(struct mqd_manager *mm, void *mqd,
    285			  void __user *ctl_stack,
    286			  u32 *ctl_stack_used_size,
    287			  u32 *save_area_used_size)
    288{
    289	struct v11_compute_mqd *m;
    290	/*struct mqd_user_context_save_area_header header;*/
    291
    292	m = get_mqd(mqd);
    293
    294	/* Control stack is written backwards, while workgroup context data
    295	 * is written forwards. Both starts from m->cp_hqd_cntl_stack_size.
    296	 * Current position is at m->cp_hqd_cntl_stack_offset and
    297	 * m->cp_hqd_wg_state_offset, respectively.
    298	 */
    299	*ctl_stack_used_size = m->cp_hqd_cntl_stack_size -
    300		m->cp_hqd_cntl_stack_offset;
    301	*save_area_used_size = m->cp_hqd_wg_state_offset -
    302		m->cp_hqd_cntl_stack_size;
    303
    304	/* Control stack is not copied to user mode for GFXv11 because
    305	 * it's part of the context save area that is already
    306	 * accessible to user mode
    307	 */
    308/*
    309	header.control_stack_size = *ctl_stack_used_size;
    310	header.wave_state_size = *save_area_used_size;
    311
    312	header.wave_state_offset = m->cp_hqd_wg_state_offset;
    313	header.control_stack_offset = m->cp_hqd_cntl_stack_offset;
    314
    315	if (copy_to_user(ctl_stack, &header, sizeof(header)))
    316		return -EFAULT;
    317*/
    318	return 0;
    319}
    320
    321static void init_mqd_hiq(struct mqd_manager *mm, void **mqd,
    322			struct kfd_mem_obj *mqd_mem_obj, uint64_t *gart_addr,
    323			struct queue_properties *q)
    324{
    325	struct v11_compute_mqd *m;
    326
    327	init_mqd(mm, mqd, mqd_mem_obj, gart_addr, q);
    328
    329	m = get_mqd(*mqd);
    330
    331	m->cp_hqd_pq_control |= 1 << CP_HQD_PQ_CONTROL__PRIV_STATE__SHIFT |
    332			1 << CP_HQD_PQ_CONTROL__KMD_QUEUE__SHIFT;
    333}
    334
    335static void init_mqd_sdma(struct mqd_manager *mm, void **mqd,
    336		struct kfd_mem_obj *mqd_mem_obj, uint64_t *gart_addr,
    337		struct queue_properties *q)
    338{
    339	struct v11_sdma_mqd *m;
    340
    341	m = (struct v11_sdma_mqd *) mqd_mem_obj->cpu_ptr;
    342
    343	memset(m, 0, sizeof(struct v11_sdma_mqd));
    344
    345	*mqd = m;
    346	if (gart_addr)
    347		*gart_addr = mqd_mem_obj->gpu_addr;
    348
    349	mm->update_mqd(mm, m, q, NULL);
    350}
    351
    352static int load_mqd_sdma(struct mqd_manager *mm, void *mqd,
    353		uint32_t pipe_id, uint32_t queue_id,
    354		struct queue_properties *p, struct mm_struct *mms)
    355{
    356	return mm->dev->kfd2kgd->hqd_sdma_load(mm->dev->adev, mqd,
    357					       (uint32_t __user *)p->write_ptr,
    358					       mms);
    359}
    360
    361#define SDMA_RLC_DUMMY_DEFAULT 0xf
    362
    363static void update_mqd_sdma(struct mqd_manager *mm, void *mqd,
    364		struct queue_properties *q,
    365		struct mqd_update_info *minfo)
    366{
    367	struct v11_sdma_mqd *m;
    368
    369	m = get_sdma_mqd(mqd);
    370	m->sdmax_rlcx_rb_cntl = (ffs(q->queue_size / sizeof(unsigned int)) - 1)
    371		<< SDMA0_QUEUE0_RB_CNTL__RB_SIZE__SHIFT |
    372		q->vmid << SDMA0_QUEUE0_RB_CNTL__RB_VMID__SHIFT |
    373		1 << SDMA0_QUEUE0_RB_CNTL__RPTR_WRITEBACK_ENABLE__SHIFT |
    374		6 << SDMA0_QUEUE0_RB_CNTL__RPTR_WRITEBACK_TIMER__SHIFT;
    375
    376	m->sdmax_rlcx_rb_base = lower_32_bits(q->queue_address >> 8);
    377	m->sdmax_rlcx_rb_base_hi = upper_32_bits(q->queue_address >> 8);
    378	m->sdmax_rlcx_rb_rptr_addr_lo = lower_32_bits((uint64_t)q->read_ptr);
    379	m->sdmax_rlcx_rb_rptr_addr_hi = upper_32_bits((uint64_t)q->read_ptr);
    380	m->sdmax_rlcx_doorbell_offset =
    381		q->doorbell_off << SDMA0_QUEUE0_DOORBELL_OFFSET__OFFSET__SHIFT;
    382
    383	m->sdma_engine_id = q->sdma_engine_id;
    384	m->sdma_queue_id = q->sdma_queue_id;
    385	m->sdmax_rlcx_dummy_reg = SDMA_RLC_DUMMY_DEFAULT;
    386
    387	q->is_active = QUEUE_IS_ACTIVE(*q);
    388}
    389
    390/*
    391 *  * preempt type here is ignored because there is only one way
    392 *  * to preempt sdma queue
    393 */
    394static int destroy_mqd_sdma(struct mqd_manager *mm, void *mqd,
    395		enum kfd_preempt_type type,
    396		unsigned int timeout, uint32_t pipe_id,
    397		uint32_t queue_id)
    398{
    399	return mm->dev->kfd2kgd->hqd_sdma_destroy(mm->dev->adev, mqd, timeout);
    400}
    401
    402static bool is_occupied_sdma(struct mqd_manager *mm, void *mqd,
    403		uint64_t queue_address, uint32_t pipe_id,
    404		uint32_t queue_id)
    405{
    406	return mm->dev->kfd2kgd->hqd_sdma_is_occupied(mm->dev->adev, mqd);
    407}
    408
    409#if defined(CONFIG_DEBUG_FS)
    410
    411static int debugfs_show_mqd(struct seq_file *m, void *data)
    412{
    413	seq_hex_dump(m, "    ", DUMP_PREFIX_OFFSET, 32, 4,
    414		     data, sizeof(struct v11_compute_mqd), false);
    415	return 0;
    416}
    417
    418static int debugfs_show_mqd_sdma(struct seq_file *m, void *data)
    419{
    420	seq_hex_dump(m, "    ", DUMP_PREFIX_OFFSET, 32, 4,
    421		     data, sizeof(struct v11_sdma_mqd), false);
    422	return 0;
    423}
    424
    425#endif
    426
    427struct mqd_manager *mqd_manager_init_v11(enum KFD_MQD_TYPE type,
    428		struct kfd_dev *dev)
    429{
    430	struct mqd_manager *mqd;
    431
    432	if (WARN_ON(type >= KFD_MQD_TYPE_MAX))
    433		return NULL;
    434
    435	mqd = kzalloc(sizeof(*mqd), GFP_KERNEL);
    436	if (!mqd)
    437		return NULL;
    438
    439	mqd->dev = dev;
    440
    441	switch (type) {
    442	case KFD_MQD_TYPE_CP:
    443		pr_debug("%s@%i\n", __func__, __LINE__);
    444		mqd->allocate_mqd = allocate_mqd;
    445		mqd->init_mqd = init_mqd;
    446		mqd->free_mqd = free_mqd;
    447		mqd->load_mqd = load_mqd;
    448		mqd->update_mqd = update_mqd;
    449		mqd->destroy_mqd = destroy_mqd;
    450		mqd->is_occupied = is_occupied;
    451		mqd->mqd_size = sizeof(struct v11_compute_mqd);
    452		mqd->get_wave_state = get_wave_state;
    453#if defined(CONFIG_DEBUG_FS)
    454		mqd->debugfs_show_mqd = debugfs_show_mqd;
    455#endif
    456		pr_debug("%s@%i\n", __func__, __LINE__);
    457		break;
    458	case KFD_MQD_TYPE_HIQ:
    459		pr_debug("%s@%i\n", __func__, __LINE__);
    460		mqd->allocate_mqd = allocate_hiq_mqd;
    461		mqd->init_mqd = init_mqd_hiq;
    462		mqd->free_mqd = free_mqd_hiq_sdma;
    463		mqd->load_mqd = hiq_load_mqd_kiq;
    464		mqd->update_mqd = update_mqd;
    465		mqd->destroy_mqd = destroy_mqd;
    466		mqd->is_occupied = is_occupied;
    467		mqd->mqd_size = sizeof(struct v11_compute_mqd);
    468#if defined(CONFIG_DEBUG_FS)
    469		mqd->debugfs_show_mqd = debugfs_show_mqd;
    470#endif
    471		mqd->read_doorbell_id = read_doorbell_id;
    472		pr_debug("%s@%i\n", __func__, __LINE__);
    473		break;
    474	case KFD_MQD_TYPE_DIQ:
    475		mqd->allocate_mqd = allocate_mqd;
    476		mqd->init_mqd = init_mqd_hiq;
    477		mqd->free_mqd = free_mqd;
    478		mqd->load_mqd = load_mqd;
    479		mqd->update_mqd = update_mqd;
    480		mqd->destroy_mqd = destroy_mqd;
    481		mqd->is_occupied = is_occupied;
    482		mqd->mqd_size = sizeof(struct v11_compute_mqd);
    483#if defined(CONFIG_DEBUG_FS)
    484		mqd->debugfs_show_mqd = debugfs_show_mqd;
    485#endif
    486		break;
    487	case KFD_MQD_TYPE_SDMA:
    488		pr_debug("%s@%i\n", __func__, __LINE__);
    489		mqd->allocate_mqd = allocate_sdma_mqd;
    490		mqd->init_mqd = init_mqd_sdma;
    491		mqd->free_mqd = free_mqd_hiq_sdma;
    492		mqd->load_mqd = load_mqd_sdma;
    493		mqd->update_mqd = update_mqd_sdma;
    494		mqd->destroy_mqd = destroy_mqd_sdma;
    495		mqd->is_occupied = is_occupied_sdma;
    496		mqd->mqd_size = sizeof(struct v11_sdma_mqd);
    497#if defined(CONFIG_DEBUG_FS)
    498		mqd->debugfs_show_mqd = debugfs_show_mqd_sdma;
    499#endif
    500		pr_debug("%s@%i\n", __func__, __LINE__);
    501		break;
    502	default:
    503		kfree(mqd);
    504		return NULL;
    505	}
    506
    507	return mqd;
    508}