2 * Copyright (C) 2008 Advanced Micro Devices, Inc.
4 * Author: Joerg Roedel <joerg.roedel@amd.com>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/scatterlist.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/stacktrace.h>
23 #include <linux/dma-debug.h>
24 #include <linux/spinlock.h>
25 #include <linux/vmalloc.h>
26 #include <linux/debugfs.h>
27 #include <linux/uaccess.h>
28 #include <linux/export.h>
29 #include <linux/device.h>
30 #include <linux/types.h>
31 #include <linux/sched.h>
32 #include <linux/ctype.h>
33 #include <linux/list.h>
34 #include <linux/slab.h>
36 #include <asm/sections.h>
38 #define HASH_SIZE 1024ULL
39 #define HASH_FN_SHIFT 13
40 #define HASH_FN_MASK (HASH_SIZE - 1)
50 MAP_ERR_CHECK_NOT_APPLICABLE
,
55 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
58 * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
59 * @list: node on pre-allocated free_entries list
60 * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
61 * @type: single, page, sg, coherent
62 * @pfn: page frame of the start address
63 * @offset: offset of mapping relative to pfn
64 * @size: length of the mapping
65 * @direction: enum dma_data_direction
66 * @sg_call_ents: 'nents' from dma_map_sg
67 * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
68 * @map_err_type: track whether dma_mapping_error() was checked
69 * @stacktrace: support backtraces when a violation is detected
71 struct dma_debug_entry
{
72 struct list_head list
;
82 enum map_err_types map_err_type
;
83 #ifdef CONFIG_STACKTRACE
84 struct stack_trace stacktrace
;
85 unsigned long st_entries
[DMA_DEBUG_STACKTRACE_ENTRIES
];
89 typedef bool (*match_fn
)(struct dma_debug_entry
*, struct dma_debug_entry
*);
92 struct list_head list
;
94 } ____cacheline_aligned_in_smp
;
96 /* Hash list to save the allocated dma addresses */
97 static struct hash_bucket dma_entry_hash
[HASH_SIZE
];
98 /* List of pre-allocated dma_debug_entry's */
99 static LIST_HEAD(free_entries
);
100 /* Lock for the list above */
101 static DEFINE_SPINLOCK(free_entries_lock
);
103 /* Global disable flag - will be set in case of an error */
104 static bool global_disable __read_mostly
;
106 /* Early initialization disable flag, set at the end of dma_debug_init */
107 static bool dma_debug_initialized __read_mostly
;
109 static inline bool dma_debug_disabled(void)
111 return global_disable
|| !dma_debug_initialized
;
114 /* Global error count */
115 static u32 error_count
;
117 /* Global error show enable*/
118 static u32 show_all_errors __read_mostly
;
119 /* Number of errors to show */
120 static u32 show_num_errors
= 1;
122 static u32 num_free_entries
;
123 static u32 min_free_entries
;
124 static u32 nr_total_entries
;
126 /* number of preallocated entries requested by kernel cmdline */
127 static u32 req_entries
;
129 /* debugfs dentry's for the stuff above */
130 static struct dentry
*dma_debug_dent __read_mostly
;
131 static struct dentry
*global_disable_dent __read_mostly
;
132 static struct dentry
*error_count_dent __read_mostly
;
133 static struct dentry
*show_all_errors_dent __read_mostly
;
134 static struct dentry
*show_num_errors_dent __read_mostly
;
135 static struct dentry
*num_free_entries_dent __read_mostly
;
136 static struct dentry
*min_free_entries_dent __read_mostly
;
137 static struct dentry
*filter_dent __read_mostly
;
139 /* per-driver filter related state */
141 #define NAME_MAX_LEN 64
143 static char current_driver_name
[NAME_MAX_LEN
] __read_mostly
;
144 static struct device_driver
*current_driver __read_mostly
;
146 static DEFINE_RWLOCK(driver_name_lock
);
148 static const char *const maperr2str
[] = {
149 [MAP_ERR_CHECK_NOT_APPLICABLE
] = "dma map error check not applicable",
150 [MAP_ERR_NOT_CHECKED
] = "dma map error not checked",
151 [MAP_ERR_CHECKED
] = "dma map error checked",
154 static const char *type2name
[4] = { "single", "page",
155 "scather-gather", "coherent" };
157 static const char *dir2name
[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
158 "DMA_FROM_DEVICE", "DMA_NONE" };
161 * The access to some variables in this macro is racy. We can't use atomic_t
162 * here because all these variables are exported to debugfs. Some of them even
163 * writeable. This is also the reason why a lock won't help much. But anyway,
164 * the races are no big deal. Here is why:
166 * error_count: the addition is racy, but the worst thing that can happen is
167 * that we don't count some errors
168 * show_num_errors: the subtraction is racy. Also no big deal because in
169 * worst case this will result in one warning more in the
170 * system log than the user configured. This variable is
171 * writeable via debugfs.
173 static inline void dump_entry_trace(struct dma_debug_entry
*entry
)
175 #ifdef CONFIG_STACKTRACE
177 pr_warning("Mapped at:\n");
178 print_stack_trace(&entry
->stacktrace
, 0);
183 static bool driver_filter(struct device
*dev
)
185 struct device_driver
*drv
;
189 /* driver filter off */
190 if (likely(!current_driver_name
[0]))
193 /* driver filter on and initialized */
194 if (current_driver
&& dev
&& dev
->driver
== current_driver
)
197 /* driver filter on, but we can't filter on a NULL device... */
201 if (current_driver
|| !current_driver_name
[0])
204 /* driver filter on but not yet initialized */
209 /* lock to protect against change of current_driver_name */
210 read_lock_irqsave(&driver_name_lock
, flags
);
214 strncmp(current_driver_name
, drv
->name
, NAME_MAX_LEN
- 1) == 0) {
215 current_driver
= drv
;
219 read_unlock_irqrestore(&driver_name_lock
, flags
);
224 #define err_printk(dev, entry, format, arg...) do { \
226 if (driver_filter(dev) && \
227 (show_all_errors || show_num_errors > 0)) { \
228 WARN(1, "%s %s: " format, \
229 dev ? dev_driver_string(dev) : "NULL", \
230 dev ? dev_name(dev) : "NULL", ## arg); \
231 dump_entry_trace(entry); \
233 if (!show_all_errors && show_num_errors > 0) \
234 show_num_errors -= 1; \
238 * Hash related functions
240 * Every DMA-API request is saved into a struct dma_debug_entry. To
241 * have quick access to these structs they are stored into a hash.
243 static int hash_fn(struct dma_debug_entry
*entry
)
246 * Hash function is based on the dma address.
247 * We use bits 20-27 here as the index into the hash
249 return (entry
->dev_addr
>> HASH_FN_SHIFT
) & HASH_FN_MASK
;
253 * Request exclusive access to a hash bucket for a given dma_debug_entry.
255 static struct hash_bucket
*get_hash_bucket(struct dma_debug_entry
*entry
,
256 unsigned long *flags
)
257 __acquires(&dma_entry_hash
[idx
].lock
)
259 int idx
= hash_fn(entry
);
260 unsigned long __flags
;
262 spin_lock_irqsave(&dma_entry_hash
[idx
].lock
, __flags
);
264 return &dma_entry_hash
[idx
];
268 * Give up exclusive access to the hash bucket
270 static void put_hash_bucket(struct hash_bucket
*bucket
,
271 unsigned long *flags
)
272 __releases(&bucket
->lock
)
274 unsigned long __flags
= *flags
;
276 spin_unlock_irqrestore(&bucket
->lock
, __flags
);
279 static bool exact_match(struct dma_debug_entry
*a
, struct dma_debug_entry
*b
)
281 return ((a
->dev_addr
== b
->dev_addr
) &&
282 (a
->dev
== b
->dev
)) ? true : false;
285 static bool containing_match(struct dma_debug_entry
*a
,
286 struct dma_debug_entry
*b
)
288 if (a
->dev
!= b
->dev
)
291 if ((b
->dev_addr
<= a
->dev_addr
) &&
292 ((b
->dev_addr
+ b
->size
) >= (a
->dev_addr
+ a
->size
)))
299 * Search a given entry in the hash bucket list
301 static struct dma_debug_entry
*__hash_bucket_find(struct hash_bucket
*bucket
,
302 struct dma_debug_entry
*ref
,
305 struct dma_debug_entry
*entry
, *ret
= NULL
;
306 int matches
= 0, match_lvl
, last_lvl
= -1;
308 list_for_each_entry(entry
, &bucket
->list
, list
) {
309 if (!match(ref
, entry
))
313 * Some drivers map the same physical address multiple
314 * times. Without a hardware IOMMU this results in the
315 * same device addresses being put into the dma-debug
316 * hash multiple times too. This can result in false
317 * positives being reported. Therefore we implement a
318 * best-fit algorithm here which returns the entry from
319 * the hash which fits best to the reference value
320 * instead of the first-fit.
324 entry
->size
== ref
->size
? ++match_lvl
: 0;
325 entry
->type
== ref
->type
? ++match_lvl
: 0;
326 entry
->direction
== ref
->direction
? ++match_lvl
: 0;
327 entry
->sg_call_ents
== ref
->sg_call_ents
? ++match_lvl
: 0;
329 if (match_lvl
== 4) {
330 /* perfect-fit - return the result */
332 } else if (match_lvl
> last_lvl
) {
334 * We found an entry that fits better then the
335 * previous one or it is the 1st match.
337 last_lvl
= match_lvl
;
343 * If we have multiple matches but no perfect-fit, just return
346 ret
= (matches
== 1) ? ret
: NULL
;
351 static struct dma_debug_entry
*bucket_find_exact(struct hash_bucket
*bucket
,
352 struct dma_debug_entry
*ref
)
354 return __hash_bucket_find(bucket
, ref
, exact_match
);
357 static struct dma_debug_entry
*bucket_find_contain(struct hash_bucket
**bucket
,
358 struct dma_debug_entry
*ref
,
359 unsigned long *flags
)
362 unsigned int max_range
= dma_get_max_seg_size(ref
->dev
);
363 struct dma_debug_entry
*entry
, index
= *ref
;
364 unsigned int range
= 0;
366 while (range
<= max_range
) {
367 entry
= __hash_bucket_find(*bucket
, ref
, containing_match
);
373 * Nothing found, go back a hash bucket
375 put_hash_bucket(*bucket
, flags
);
376 range
+= (1 << HASH_FN_SHIFT
);
377 index
.dev_addr
-= (1 << HASH_FN_SHIFT
);
378 *bucket
= get_hash_bucket(&index
, flags
);
385 * Add an entry to a hash bucket
387 static void hash_bucket_add(struct hash_bucket
*bucket
,
388 struct dma_debug_entry
*entry
)
390 list_add_tail(&entry
->list
, &bucket
->list
);
394 * Remove entry from a hash bucket list
396 static void hash_bucket_del(struct dma_debug_entry
*entry
)
398 list_del(&entry
->list
);
401 static unsigned long long phys_addr(struct dma_debug_entry
*entry
)
403 return page_to_phys(pfn_to_page(entry
->pfn
)) + entry
->offset
;
407 * Dump mapping entries for debugging purposes
409 void debug_dma_dump_mappings(struct device
*dev
)
413 for (idx
= 0; idx
< HASH_SIZE
; idx
++) {
414 struct hash_bucket
*bucket
= &dma_entry_hash
[idx
];
415 struct dma_debug_entry
*entry
;
418 spin_lock_irqsave(&bucket
->lock
, flags
);
420 list_for_each_entry(entry
, &bucket
->list
, list
) {
421 if (!dev
|| dev
== entry
->dev
) {
423 "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
424 type2name
[entry
->type
], idx
,
425 phys_addr(entry
), entry
->pfn
,
426 entry
->dev_addr
, entry
->size
,
427 dir2name
[entry
->direction
],
428 maperr2str
[entry
->map_err_type
]);
432 spin_unlock_irqrestore(&bucket
->lock
, flags
);
435 EXPORT_SYMBOL(debug_dma_dump_mappings
);
438 * For each mapping (initial cacheline in the case of
439 * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
440 * scatterlist, or the cacheline specified in dma_map_single) insert
441 * into this tree using the cacheline as the key. At
442 * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry. If
443 * the entry already exists at insertion time add a tag as a reference
444 * count for the overlapping mappings. For now, the overlap tracking
445 * just ensures that 'unmaps' balance 'maps' before marking the
446 * cacheline idle, but we should also be flagging overlaps as an API
449 * Memory usage is mostly constrained by the maximum number of available
450 * dma-debug entries in that we need a free dma_debug_entry before
451 * inserting into the tree. In the case of dma_map_page and
452 * dma_alloc_coherent there is only one dma_debug_entry and one
453 * dma_active_cacheline entry to track per event. dma_map_sg(), on the
454 * other hand, consumes a single dma_debug_entry, but inserts 'nents'
455 * entries into the tree.
457 * At any time debug_dma_assert_idle() can be called to trigger a
458 * warning if any cachelines in the given page are in the active set.
460 static RADIX_TREE(dma_active_cacheline
, GFP_NOWAIT
);
461 static DEFINE_SPINLOCK(radix_lock
);
462 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
463 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
464 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
466 static phys_addr_t
to_cacheline_number(struct dma_debug_entry
*entry
)
468 return (entry
->pfn
<< CACHELINE_PER_PAGE_SHIFT
) +
469 (entry
->offset
>> L1_CACHE_SHIFT
);
472 static int active_cacheline_read_overlap(phys_addr_t cln
)
476 for (i
= RADIX_TREE_MAX_TAGS
- 1; i
>= 0; i
--)
477 if (radix_tree_tag_get(&dma_active_cacheline
, cln
, i
))
482 static int active_cacheline_set_overlap(phys_addr_t cln
, int overlap
)
486 if (overlap
> ACTIVE_CACHELINE_MAX_OVERLAP
|| overlap
< 0)
489 for (i
= RADIX_TREE_MAX_TAGS
- 1; i
>= 0; i
--)
490 if (overlap
& 1 << i
)
491 radix_tree_tag_set(&dma_active_cacheline
, cln
, i
);
493 radix_tree_tag_clear(&dma_active_cacheline
, cln
, i
);
498 static void active_cacheline_inc_overlap(phys_addr_t cln
)
500 int overlap
= active_cacheline_read_overlap(cln
);
502 overlap
= active_cacheline_set_overlap(cln
, ++overlap
);
504 /* If we overflowed the overlap counter then we're potentially
505 * leaking dma-mappings. Otherwise, if maps and unmaps are
506 * balanced then this overflow may cause false negatives in
507 * debug_dma_assert_idle() as the cacheline may be marked idle
510 WARN_ONCE(overlap
> ACTIVE_CACHELINE_MAX_OVERLAP
,
511 "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
512 ACTIVE_CACHELINE_MAX_OVERLAP
, &cln
);
515 static int active_cacheline_dec_overlap(phys_addr_t cln
)
517 int overlap
= active_cacheline_read_overlap(cln
);
519 return active_cacheline_set_overlap(cln
, --overlap
);
522 static int active_cacheline_insert(struct dma_debug_entry
*entry
)
524 phys_addr_t cln
= to_cacheline_number(entry
);
528 /* If the device is not writing memory then we don't have any
529 * concerns about the cpu consuming stale data. This mitigates
530 * legitimate usages of overlapping mappings.
532 if (entry
->direction
== DMA_TO_DEVICE
)
535 spin_lock_irqsave(&radix_lock
, flags
);
536 rc
= radix_tree_insert(&dma_active_cacheline
, cln
, entry
);
538 active_cacheline_inc_overlap(cln
);
539 spin_unlock_irqrestore(&radix_lock
, flags
);
544 static void active_cacheline_remove(struct dma_debug_entry
*entry
)
546 phys_addr_t cln
= to_cacheline_number(entry
);
549 /* ...mirror the insert case */
550 if (entry
->direction
== DMA_TO_DEVICE
)
553 spin_lock_irqsave(&radix_lock
, flags
);
554 /* since we are counting overlaps the final put of the
555 * cacheline will occur when the overlap count is 0.
556 * active_cacheline_dec_overlap() returns -1 in that case
558 if (active_cacheline_dec_overlap(cln
) < 0)
559 radix_tree_delete(&dma_active_cacheline
, cln
);
560 spin_unlock_irqrestore(&radix_lock
, flags
);
564 * debug_dma_assert_idle() - assert that a page is not undergoing dma
565 * @page: page to lookup in the dma_active_cacheline tree
567 * Place a call to this routine in cases where the cpu touching the page
568 * before the dma completes (page is dma_unmapped) will lead to data
571 void debug_dma_assert_idle(struct page
*page
)
573 static struct dma_debug_entry
*ents
[CACHELINES_PER_PAGE
];
574 struct dma_debug_entry
*entry
= NULL
;
575 void **results
= (void **) &ents
;
576 unsigned int nents
, i
;
580 if (dma_debug_disabled())
586 cln
= (phys_addr_t
) page_to_pfn(page
) << CACHELINE_PER_PAGE_SHIFT
;
587 spin_lock_irqsave(&radix_lock
, flags
);
588 nents
= radix_tree_gang_lookup(&dma_active_cacheline
, results
, cln
,
589 CACHELINES_PER_PAGE
);
590 for (i
= 0; i
< nents
; i
++) {
591 phys_addr_t ent_cln
= to_cacheline_number(ents
[i
]);
593 if (ent_cln
== cln
) {
596 } else if (ent_cln
>= cln
+ CACHELINES_PER_PAGE
)
599 spin_unlock_irqrestore(&radix_lock
, flags
);
604 cln
= to_cacheline_number(entry
);
605 err_printk(entry
->dev
, entry
,
606 "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
611 * Wrapper function for adding an entry to the hash.
612 * This function takes care of locking itself.
614 static void add_dma_entry(struct dma_debug_entry
*entry
)
616 struct hash_bucket
*bucket
;
620 bucket
= get_hash_bucket(entry
, &flags
);
621 hash_bucket_add(bucket
, entry
);
622 put_hash_bucket(bucket
, &flags
);
624 rc
= active_cacheline_insert(entry
);
626 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
627 global_disable
= true;
630 /* TODO: report -EEXIST errors here as overlapping mappings are
631 * not supported by the DMA API
635 static struct dma_debug_entry
*__dma_entry_alloc(void)
637 struct dma_debug_entry
*entry
;
639 entry
= list_entry(free_entries
.next
, struct dma_debug_entry
, list
);
640 list_del(&entry
->list
);
641 memset(entry
, 0, sizeof(*entry
));
643 num_free_entries
-= 1;
644 if (num_free_entries
< min_free_entries
)
645 min_free_entries
= num_free_entries
;
650 /* struct dma_entry allocator
652 * The next two functions implement the allocator for
653 * struct dma_debug_entries.
655 static struct dma_debug_entry
*dma_entry_alloc(void)
657 struct dma_debug_entry
*entry
;
660 spin_lock_irqsave(&free_entries_lock
, flags
);
662 if (list_empty(&free_entries
)) {
663 global_disable
= true;
664 spin_unlock_irqrestore(&free_entries_lock
, flags
);
665 pr_err("DMA-API: debugging out of memory - disabling\n");
669 entry
= __dma_entry_alloc();
671 spin_unlock_irqrestore(&free_entries_lock
, flags
);
673 #ifdef CONFIG_STACKTRACE
674 entry
->stacktrace
.max_entries
= DMA_DEBUG_STACKTRACE_ENTRIES
;
675 entry
->stacktrace
.entries
= entry
->st_entries
;
676 entry
->stacktrace
.skip
= 2;
677 save_stack_trace(&entry
->stacktrace
);
683 static void dma_entry_free(struct dma_debug_entry
*entry
)
687 active_cacheline_remove(entry
);
690 * add to beginning of the list - this way the entries are
691 * more likely cache hot when they are reallocated.
693 spin_lock_irqsave(&free_entries_lock
, flags
);
694 list_add(&entry
->list
, &free_entries
);
695 num_free_entries
+= 1;
696 spin_unlock_irqrestore(&free_entries_lock
, flags
);
699 int dma_debug_resize_entries(u32 num_entries
)
701 int i
, delta
, ret
= 0;
703 struct dma_debug_entry
*entry
;
706 spin_lock_irqsave(&free_entries_lock
, flags
);
708 if (nr_total_entries
< num_entries
) {
709 delta
= num_entries
- nr_total_entries
;
711 spin_unlock_irqrestore(&free_entries_lock
, flags
);
713 for (i
= 0; i
< delta
; i
++) {
714 entry
= kzalloc(sizeof(*entry
), GFP_KERNEL
);
718 list_add_tail(&entry
->list
, &tmp
);
721 spin_lock_irqsave(&free_entries_lock
, flags
);
723 list_splice(&tmp
, &free_entries
);
724 nr_total_entries
+= i
;
725 num_free_entries
+= i
;
727 delta
= nr_total_entries
- num_entries
;
729 for (i
= 0; i
< delta
&& !list_empty(&free_entries
); i
++) {
730 entry
= __dma_entry_alloc();
734 nr_total_entries
-= i
;
737 if (nr_total_entries
!= num_entries
)
740 spin_unlock_irqrestore(&free_entries_lock
, flags
);
744 EXPORT_SYMBOL(dma_debug_resize_entries
);
747 * DMA-API debugging init code
749 * The init code does two things:
750 * 1. Initialize core data structures
751 * 2. Preallocate a given number of dma_debug_entry structs
754 static int prealloc_memory(u32 num_entries
)
756 struct dma_debug_entry
*entry
, *next_entry
;
759 for (i
= 0; i
< num_entries
; ++i
) {
760 entry
= kzalloc(sizeof(*entry
), GFP_KERNEL
);
764 list_add_tail(&entry
->list
, &free_entries
);
767 num_free_entries
= num_entries
;
768 min_free_entries
= num_entries
;
770 pr_info("DMA-API: preallocated %d debug entries\n", num_entries
);
776 list_for_each_entry_safe(entry
, next_entry
, &free_entries
, list
) {
777 list_del(&entry
->list
);
784 static ssize_t
filter_read(struct file
*file
, char __user
*user_buf
,
785 size_t count
, loff_t
*ppos
)
787 char buf
[NAME_MAX_LEN
+ 1];
791 if (!current_driver_name
[0])
795 * We can't copy to userspace directly because current_driver_name can
796 * only be read under the driver_name_lock with irqs disabled. So
797 * create a temporary copy first.
799 read_lock_irqsave(&driver_name_lock
, flags
);
800 len
= scnprintf(buf
, NAME_MAX_LEN
+ 1, "%s\n", current_driver_name
);
801 read_unlock_irqrestore(&driver_name_lock
, flags
);
803 return simple_read_from_buffer(user_buf
, count
, ppos
, buf
, len
);
806 static ssize_t
filter_write(struct file
*file
, const char __user
*userbuf
,
807 size_t count
, loff_t
*ppos
)
809 char buf
[NAME_MAX_LEN
];
815 * We can't copy from userspace directly. Access to
816 * current_driver_name is protected with a write_lock with irqs
817 * disabled. Since copy_from_user can fault and may sleep we
818 * need to copy to temporary buffer first
820 len
= min(count
, (size_t)(NAME_MAX_LEN
- 1));
821 if (copy_from_user(buf
, userbuf
, len
))
826 write_lock_irqsave(&driver_name_lock
, flags
);
829 * Now handle the string we got from userspace very carefully.
831 * - only use the first token we got
832 * - token delimiter is everything looking like a space
833 * character (' ', '\n', '\t' ...)
836 if (!isalnum(buf
[0])) {
838 * If the first character userspace gave us is not
839 * alphanumerical then assume the filter should be
842 if (current_driver_name
[0])
843 pr_info("DMA-API: switching off dma-debug driver filter\n");
844 current_driver_name
[0] = 0;
845 current_driver
= NULL
;
850 * Now parse out the first token and use it as the name for the
851 * driver to filter for.
853 for (i
= 0; i
< NAME_MAX_LEN
- 1; ++i
) {
854 current_driver_name
[i
] = buf
[i
];
855 if (isspace(buf
[i
]) || buf
[i
] == ' ' || buf
[i
] == 0)
858 current_driver_name
[i
] = 0;
859 current_driver
= NULL
;
861 pr_info("DMA-API: enable driver filter for driver [%s]\n",
862 current_driver_name
);
865 write_unlock_irqrestore(&driver_name_lock
, flags
);
870 static const struct file_operations filter_fops
= {
872 .write
= filter_write
,
873 .llseek
= default_llseek
,
876 static int dma_debug_fs_init(void)
878 dma_debug_dent
= debugfs_create_dir("dma-api", NULL
);
879 if (!dma_debug_dent
) {
880 pr_err("DMA-API: can not create debugfs directory\n");
884 global_disable_dent
= debugfs_create_bool("disabled", 0444,
887 if (!global_disable_dent
)
890 error_count_dent
= debugfs_create_u32("error_count", 0444,
891 dma_debug_dent
, &error_count
);
892 if (!error_count_dent
)
895 show_all_errors_dent
= debugfs_create_u32("all_errors", 0644,
898 if (!show_all_errors_dent
)
901 show_num_errors_dent
= debugfs_create_u32("num_errors", 0644,
904 if (!show_num_errors_dent
)
907 num_free_entries_dent
= debugfs_create_u32("num_free_entries", 0444,
910 if (!num_free_entries_dent
)
913 min_free_entries_dent
= debugfs_create_u32("min_free_entries", 0444,
916 if (!min_free_entries_dent
)
919 filter_dent
= debugfs_create_file("driver_filter", 0644,
920 dma_debug_dent
, NULL
, &filter_fops
);
927 debugfs_remove_recursive(dma_debug_dent
);
932 static int device_dma_allocations(struct device
*dev
, struct dma_debug_entry
**out_entry
)
934 struct dma_debug_entry
*entry
;
938 local_irq_save(flags
);
940 for (i
= 0; i
< HASH_SIZE
; ++i
) {
941 spin_lock(&dma_entry_hash
[i
].lock
);
942 list_for_each_entry(entry
, &dma_entry_hash
[i
].list
, list
) {
943 if (entry
->dev
== dev
) {
948 spin_unlock(&dma_entry_hash
[i
].lock
);
951 local_irq_restore(flags
);
956 static int dma_debug_device_change(struct notifier_block
*nb
, unsigned long action
, void *data
)
958 struct device
*dev
= data
;
959 struct dma_debug_entry
*uninitialized_var(entry
);
962 if (dma_debug_disabled())
966 case BUS_NOTIFY_UNBOUND_DRIVER
:
967 count
= device_dma_allocations(dev
, &entry
);
970 err_printk(dev
, entry
, "DMA-API: device driver has pending "
971 "DMA allocations while released from device "
973 "One of leaked entries details: "
974 "[device address=0x%016llx] [size=%llu bytes] "
975 "[mapped with %s] [mapped as %s]\n",
976 count
, entry
->dev_addr
, entry
->size
,
977 dir2name
[entry
->direction
], type2name
[entry
->type
]);
986 void dma_debug_add_bus(struct bus_type
*bus
)
988 struct notifier_block
*nb
;
990 if (dma_debug_disabled())
993 nb
= kzalloc(sizeof(struct notifier_block
), GFP_KERNEL
);
995 pr_err("dma_debug_add_bus: out of memory\n");
999 nb
->notifier_call
= dma_debug_device_change
;
1001 bus_register_notifier(bus
, nb
);
1005 * Let the architectures decide how many entries should be preallocated.
1007 void dma_debug_init(u32 num_entries
)
1011 /* Do not use dma_debug_initialized here, since we really want to be
1012 * called to set dma_debug_initialized
1017 for (i
= 0; i
< HASH_SIZE
; ++i
) {
1018 INIT_LIST_HEAD(&dma_entry_hash
[i
].list
);
1019 spin_lock_init(&dma_entry_hash
[i
].lock
);
1022 if (dma_debug_fs_init() != 0) {
1023 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1024 global_disable
= true;
1030 num_entries
= req_entries
;
1032 if (prealloc_memory(num_entries
) != 0) {
1033 pr_err("DMA-API: debugging out of memory error - disabled\n");
1034 global_disable
= true;
1039 nr_total_entries
= num_free_entries
;
1041 dma_debug_initialized
= true;
1043 pr_info("DMA-API: debugging enabled by kernel config\n");
1046 static __init
int dma_debug_cmdline(char *str
)
1051 if (strncmp(str
, "off", 3) == 0) {
1052 pr_info("DMA-API: debugging disabled on kernel command line\n");
1053 global_disable
= true;
1059 static __init
int dma_debug_entries_cmdline(char *str
)
1066 res
= get_option(&str
, &req_entries
);
1074 __setup("dma_debug=", dma_debug_cmdline
);
1075 __setup("dma_debug_entries=", dma_debug_entries_cmdline
);
1077 static void check_unmap(struct dma_debug_entry
*ref
)
1079 struct dma_debug_entry
*entry
;
1080 struct hash_bucket
*bucket
;
1081 unsigned long flags
;
1083 bucket
= get_hash_bucket(ref
, &flags
);
1084 entry
= bucket_find_exact(bucket
, ref
);
1087 /* must drop lock before calling dma_mapping_error */
1088 put_hash_bucket(bucket
, &flags
);
1090 if (dma_mapping_error(ref
->dev
, ref
->dev_addr
)) {
1091 err_printk(ref
->dev
, NULL
,
1092 "DMA-API: device driver tries to free an "
1093 "invalid DMA memory address\n");
1095 err_printk(ref
->dev
, NULL
,
1096 "DMA-API: device driver tries to free DMA "
1097 "memory it has not allocated [device "
1098 "address=0x%016llx] [size=%llu bytes]\n",
1099 ref
->dev_addr
, ref
->size
);
1104 if (ref
->size
!= entry
->size
) {
1105 err_printk(ref
->dev
, entry
, "DMA-API: device driver frees "
1106 "DMA memory with different size "
1107 "[device address=0x%016llx] [map size=%llu bytes] "
1108 "[unmap size=%llu bytes]\n",
1109 ref
->dev_addr
, entry
->size
, ref
->size
);
1112 if (ref
->type
!= entry
->type
) {
1113 err_printk(ref
->dev
, entry
, "DMA-API: device driver frees "
1114 "DMA memory with wrong function "
1115 "[device address=0x%016llx] [size=%llu bytes] "
1116 "[mapped as %s] [unmapped as %s]\n",
1117 ref
->dev_addr
, ref
->size
,
1118 type2name
[entry
->type
], type2name
[ref
->type
]);
1119 } else if ((entry
->type
== dma_debug_coherent
) &&
1120 (phys_addr(ref
) != phys_addr(entry
))) {
1121 err_printk(ref
->dev
, entry
, "DMA-API: device driver frees "
1122 "DMA memory with different CPU address "
1123 "[device address=0x%016llx] [size=%llu bytes] "
1124 "[cpu alloc address=0x%016llx] "
1125 "[cpu free address=0x%016llx]",
1126 ref
->dev_addr
, ref
->size
,
1131 if (ref
->sg_call_ents
&& ref
->type
== dma_debug_sg
&&
1132 ref
->sg_call_ents
!= entry
->sg_call_ents
) {
1133 err_printk(ref
->dev
, entry
, "DMA-API: device driver frees "
1134 "DMA sg list with different entry count "
1135 "[map count=%d] [unmap count=%d]\n",
1136 entry
->sg_call_ents
, ref
->sg_call_ents
);
1140 * This may be no bug in reality - but most implementations of the
1141 * DMA API don't handle this properly, so check for it here
1143 if (ref
->direction
!= entry
->direction
) {
1144 err_printk(ref
->dev
, entry
, "DMA-API: device driver frees "
1145 "DMA memory with different direction "
1146 "[device address=0x%016llx] [size=%llu bytes] "
1147 "[mapped with %s] [unmapped with %s]\n",
1148 ref
->dev_addr
, ref
->size
,
1149 dir2name
[entry
->direction
],
1150 dir2name
[ref
->direction
]);
1153 if (entry
->map_err_type
== MAP_ERR_NOT_CHECKED
) {
1154 err_printk(ref
->dev
, entry
,
1155 "DMA-API: device driver failed to check map error"
1156 "[device address=0x%016llx] [size=%llu bytes] "
1158 ref
->dev_addr
, ref
->size
,
1159 type2name
[entry
->type
]);
1162 hash_bucket_del(entry
);
1163 dma_entry_free(entry
);
1165 put_hash_bucket(bucket
, &flags
);
1168 static void check_for_stack(struct device
*dev
,
1169 struct page
*page
, size_t offset
)
1172 struct vm_struct
*stack_vm_area
= task_stack_vm_area(current
);
1174 if (!stack_vm_area
) {
1175 /* Stack is direct-mapped. */
1176 if (PageHighMem(page
))
1178 addr
= page_address(page
) + offset
;
1179 if (object_is_on_stack(addr
))
1180 err_printk(dev
, NULL
, "DMA-API: device driver maps memory from stack [addr=%p]\n", addr
);
1182 /* Stack is vmalloced. */
1185 for (i
= 0; i
< stack_vm_area
->nr_pages
; i
++) {
1186 if (page
!= stack_vm_area
->pages
[i
])
1189 addr
= (u8
*)current
->stack
+ i
* PAGE_SIZE
+ offset
;
1190 err_printk(dev
, NULL
, "DMA-API: device driver maps memory from stack [probable addr=%p]\n", addr
);
1196 static inline bool overlap(void *addr
, unsigned long len
, void *start
, void *end
)
1198 unsigned long a1
= (unsigned long)addr
;
1199 unsigned long b1
= a1
+ len
;
1200 unsigned long a2
= (unsigned long)start
;
1201 unsigned long b2
= (unsigned long)end
;
1203 return !(b1
<= a2
|| a1
>= b2
);
1206 static void check_for_illegal_area(struct device
*dev
, void *addr
, unsigned long len
)
1208 if (overlap(addr
, len
, _stext
, _etext
) ||
1209 overlap(addr
, len
, __start_rodata
, __end_rodata
))
1210 err_printk(dev
, NULL
, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr
, len
);
1213 static void check_sync(struct device
*dev
,
1214 struct dma_debug_entry
*ref
,
1217 struct dma_debug_entry
*entry
;
1218 struct hash_bucket
*bucket
;
1219 unsigned long flags
;
1221 bucket
= get_hash_bucket(ref
, &flags
);
1223 entry
= bucket_find_contain(&bucket
, ref
, &flags
);
1226 err_printk(dev
, NULL
, "DMA-API: device driver tries "
1227 "to sync DMA memory it has not allocated "
1228 "[device address=0x%016llx] [size=%llu bytes]\n",
1229 (unsigned long long)ref
->dev_addr
, ref
->size
);
1233 if (ref
->size
> entry
->size
) {
1234 err_printk(dev
, entry
, "DMA-API: device driver syncs"
1235 " DMA memory outside allocated range "
1236 "[device address=0x%016llx] "
1237 "[allocation size=%llu bytes] "
1238 "[sync offset+size=%llu]\n",
1239 entry
->dev_addr
, entry
->size
,
1243 if (entry
->direction
== DMA_BIDIRECTIONAL
)
1246 if (ref
->direction
!= entry
->direction
) {
1247 err_printk(dev
, entry
, "DMA-API: device driver syncs "
1248 "DMA memory with different direction "
1249 "[device address=0x%016llx] [size=%llu bytes] "
1250 "[mapped with %s] [synced with %s]\n",
1251 (unsigned long long)ref
->dev_addr
, entry
->size
,
1252 dir2name
[entry
->direction
],
1253 dir2name
[ref
->direction
]);
1256 if (to_cpu
&& !(entry
->direction
== DMA_FROM_DEVICE
) &&
1257 !(ref
->direction
== DMA_TO_DEVICE
))
1258 err_printk(dev
, entry
, "DMA-API: device driver syncs "
1259 "device read-only DMA memory for cpu "
1260 "[device address=0x%016llx] [size=%llu bytes] "
1261 "[mapped with %s] [synced with %s]\n",
1262 (unsigned long long)ref
->dev_addr
, entry
->size
,
1263 dir2name
[entry
->direction
],
1264 dir2name
[ref
->direction
]);
1266 if (!to_cpu
&& !(entry
->direction
== DMA_TO_DEVICE
) &&
1267 !(ref
->direction
== DMA_FROM_DEVICE
))
1268 err_printk(dev
, entry
, "DMA-API: device driver syncs "
1269 "device write-only DMA memory to device "
1270 "[device address=0x%016llx] [size=%llu bytes] "
1271 "[mapped with %s] [synced with %s]\n",
1272 (unsigned long long)ref
->dev_addr
, entry
->size
,
1273 dir2name
[entry
->direction
],
1274 dir2name
[ref
->direction
]);
1276 if (ref
->sg_call_ents
&& ref
->type
== dma_debug_sg
&&
1277 ref
->sg_call_ents
!= entry
->sg_call_ents
) {
1278 err_printk(ref
->dev
, entry
, "DMA-API: device driver syncs "
1279 "DMA sg list with different entry count "
1280 "[map count=%d] [sync count=%d]\n",
1281 entry
->sg_call_ents
, ref
->sg_call_ents
);
1285 put_hash_bucket(bucket
, &flags
);
1288 void debug_dma_map_page(struct device
*dev
, struct page
*page
, size_t offset
,
1289 size_t size
, int direction
, dma_addr_t dma_addr
,
1292 struct dma_debug_entry
*entry
;
1294 if (unlikely(dma_debug_disabled()))
1297 if (dma_mapping_error(dev
, dma_addr
))
1300 entry
= dma_entry_alloc();
1305 entry
->type
= dma_debug_page
;
1306 entry
->pfn
= page_to_pfn(page
);
1307 entry
->offset
= offset
,
1308 entry
->dev_addr
= dma_addr
;
1310 entry
->direction
= direction
;
1311 entry
->map_err_type
= MAP_ERR_NOT_CHECKED
;
1314 entry
->type
= dma_debug_single
;
1316 check_for_stack(dev
, page
, offset
);
1318 if (!PageHighMem(page
)) {
1319 void *addr
= page_address(page
) + offset
;
1321 check_for_illegal_area(dev
, addr
, size
);
1324 add_dma_entry(entry
);
1326 EXPORT_SYMBOL(debug_dma_map_page
);
1328 void debug_dma_mapping_error(struct device
*dev
, dma_addr_t dma_addr
)
1330 struct dma_debug_entry ref
;
1331 struct dma_debug_entry
*entry
;
1332 struct hash_bucket
*bucket
;
1333 unsigned long flags
;
1335 if (unlikely(dma_debug_disabled()))
1339 ref
.dev_addr
= dma_addr
;
1340 bucket
= get_hash_bucket(&ref
, &flags
);
1342 list_for_each_entry(entry
, &bucket
->list
, list
) {
1343 if (!exact_match(&ref
, entry
))
1347 * The same physical address can be mapped multiple
1348 * times. Without a hardware IOMMU this results in the
1349 * same device addresses being put into the dma-debug
1350 * hash multiple times too. This can result in false
1351 * positives being reported. Therefore we implement a
1352 * best-fit algorithm here which updates the first entry
1353 * from the hash which fits the reference value and is
1354 * not currently listed as being checked.
1356 if (entry
->map_err_type
== MAP_ERR_NOT_CHECKED
) {
1357 entry
->map_err_type
= MAP_ERR_CHECKED
;
1362 put_hash_bucket(bucket
, &flags
);
1364 EXPORT_SYMBOL(debug_dma_mapping_error
);
1366 void debug_dma_unmap_page(struct device
*dev
, dma_addr_t addr
,
1367 size_t size
, int direction
, bool map_single
)
1369 struct dma_debug_entry ref
= {
1370 .type
= dma_debug_page
,
1374 .direction
= direction
,
1377 if (unlikely(dma_debug_disabled()))
1381 ref
.type
= dma_debug_single
;
1385 EXPORT_SYMBOL(debug_dma_unmap_page
);
1387 void debug_dma_map_sg(struct device
*dev
, struct scatterlist
*sg
,
1388 int nents
, int mapped_ents
, int direction
)
1390 struct dma_debug_entry
*entry
;
1391 struct scatterlist
*s
;
1394 if (unlikely(dma_debug_disabled()))
1397 for_each_sg(sg
, s
, mapped_ents
, i
) {
1398 entry
= dma_entry_alloc();
1402 entry
->type
= dma_debug_sg
;
1404 entry
->pfn
= page_to_pfn(sg_page(s
));
1405 entry
->offset
= s
->offset
,
1406 entry
->size
= sg_dma_len(s
);
1407 entry
->dev_addr
= sg_dma_address(s
);
1408 entry
->direction
= direction
;
1409 entry
->sg_call_ents
= nents
;
1410 entry
->sg_mapped_ents
= mapped_ents
;
1412 check_for_stack(dev
, sg_page(s
), s
->offset
);
1414 if (!PageHighMem(sg_page(s
))) {
1415 check_for_illegal_area(dev
, sg_virt(s
), sg_dma_len(s
));
1418 add_dma_entry(entry
);
1421 EXPORT_SYMBOL(debug_dma_map_sg
);
1423 static int get_nr_mapped_entries(struct device
*dev
,
1424 struct dma_debug_entry
*ref
)
1426 struct dma_debug_entry
*entry
;
1427 struct hash_bucket
*bucket
;
1428 unsigned long flags
;
1431 bucket
= get_hash_bucket(ref
, &flags
);
1432 entry
= bucket_find_exact(bucket
, ref
);
1436 mapped_ents
= entry
->sg_mapped_ents
;
1437 put_hash_bucket(bucket
, &flags
);
1442 void debug_dma_unmap_sg(struct device
*dev
, struct scatterlist
*sglist
,
1443 int nelems
, int dir
)
1445 struct scatterlist
*s
;
1446 int mapped_ents
= 0, i
;
1448 if (unlikely(dma_debug_disabled()))
1451 for_each_sg(sglist
, s
, nelems
, i
) {
1453 struct dma_debug_entry ref
= {
1454 .type
= dma_debug_sg
,
1456 .pfn
= page_to_pfn(sg_page(s
)),
1457 .offset
= s
->offset
,
1458 .dev_addr
= sg_dma_address(s
),
1459 .size
= sg_dma_len(s
),
1461 .sg_call_ents
= nelems
,
1464 if (mapped_ents
&& i
>= mapped_ents
)
1468 mapped_ents
= get_nr_mapped_entries(dev
, &ref
);
1473 EXPORT_SYMBOL(debug_dma_unmap_sg
);
1475 void debug_dma_alloc_coherent(struct device
*dev
, size_t size
,
1476 dma_addr_t dma_addr
, void *virt
)
1478 struct dma_debug_entry
*entry
;
1480 if (unlikely(dma_debug_disabled()))
1483 if (unlikely(virt
== NULL
))
1486 entry
= dma_entry_alloc();
1490 entry
->type
= dma_debug_coherent
;
1492 entry
->pfn
= page_to_pfn(virt_to_page(virt
));
1493 entry
->offset
= (size_t) virt
& ~PAGE_MASK
;
1495 entry
->dev_addr
= dma_addr
;
1496 entry
->direction
= DMA_BIDIRECTIONAL
;
1498 add_dma_entry(entry
);
1500 EXPORT_SYMBOL(debug_dma_alloc_coherent
);
1502 void debug_dma_free_coherent(struct device
*dev
, size_t size
,
1503 void *virt
, dma_addr_t addr
)
1505 struct dma_debug_entry ref
= {
1506 .type
= dma_debug_coherent
,
1508 .pfn
= page_to_pfn(virt_to_page(virt
)),
1509 .offset
= (size_t) virt
& ~PAGE_MASK
,
1512 .direction
= DMA_BIDIRECTIONAL
,
1515 if (unlikely(dma_debug_disabled()))
1520 EXPORT_SYMBOL(debug_dma_free_coherent
);
1522 void debug_dma_sync_single_for_cpu(struct device
*dev
, dma_addr_t dma_handle
,
1523 size_t size
, int direction
)
1525 struct dma_debug_entry ref
;
1527 if (unlikely(dma_debug_disabled()))
1530 ref
.type
= dma_debug_single
;
1532 ref
.dev_addr
= dma_handle
;
1534 ref
.direction
= direction
;
1535 ref
.sg_call_ents
= 0;
1537 check_sync(dev
, &ref
, true);
1539 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu
);
1541 void debug_dma_sync_single_for_device(struct device
*dev
,
1542 dma_addr_t dma_handle
, size_t size
,
1545 struct dma_debug_entry ref
;
1547 if (unlikely(dma_debug_disabled()))
1550 ref
.type
= dma_debug_single
;
1552 ref
.dev_addr
= dma_handle
;
1554 ref
.direction
= direction
;
1555 ref
.sg_call_ents
= 0;
1557 check_sync(dev
, &ref
, false);
1559 EXPORT_SYMBOL(debug_dma_sync_single_for_device
);
1561 void debug_dma_sync_single_range_for_cpu(struct device
*dev
,
1562 dma_addr_t dma_handle
,
1563 unsigned long offset
, size_t size
,
1566 struct dma_debug_entry ref
;
1568 if (unlikely(dma_debug_disabled()))
1571 ref
.type
= dma_debug_single
;
1573 ref
.dev_addr
= dma_handle
;
1574 ref
.size
= offset
+ size
;
1575 ref
.direction
= direction
;
1576 ref
.sg_call_ents
= 0;
1578 check_sync(dev
, &ref
, true);
1580 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu
);
1582 void debug_dma_sync_single_range_for_device(struct device
*dev
,
1583 dma_addr_t dma_handle
,
1584 unsigned long offset
,
1585 size_t size
, int direction
)
1587 struct dma_debug_entry ref
;
1589 if (unlikely(dma_debug_disabled()))
1592 ref
.type
= dma_debug_single
;
1594 ref
.dev_addr
= dma_handle
;
1595 ref
.size
= offset
+ size
;
1596 ref
.direction
= direction
;
1597 ref
.sg_call_ents
= 0;
1599 check_sync(dev
, &ref
, false);
1601 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device
);
1603 void debug_dma_sync_sg_for_cpu(struct device
*dev
, struct scatterlist
*sg
,
1604 int nelems
, int direction
)
1606 struct scatterlist
*s
;
1607 int mapped_ents
= 0, i
;
1609 if (unlikely(dma_debug_disabled()))
1612 for_each_sg(sg
, s
, nelems
, i
) {
1614 struct dma_debug_entry ref
= {
1615 .type
= dma_debug_sg
,
1617 .pfn
= page_to_pfn(sg_page(s
)),
1618 .offset
= s
->offset
,
1619 .dev_addr
= sg_dma_address(s
),
1620 .size
= sg_dma_len(s
),
1621 .direction
= direction
,
1622 .sg_call_ents
= nelems
,
1626 mapped_ents
= get_nr_mapped_entries(dev
, &ref
);
1628 if (i
>= mapped_ents
)
1631 check_sync(dev
, &ref
, true);
1634 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu
);
1636 void debug_dma_sync_sg_for_device(struct device
*dev
, struct scatterlist
*sg
,
1637 int nelems
, int direction
)
1639 struct scatterlist
*s
;
1640 int mapped_ents
= 0, i
;
1642 if (unlikely(dma_debug_disabled()))
1645 for_each_sg(sg
, s
, nelems
, i
) {
1647 struct dma_debug_entry ref
= {
1648 .type
= dma_debug_sg
,
1650 .pfn
= page_to_pfn(sg_page(s
)),
1651 .offset
= s
->offset
,
1652 .dev_addr
= sg_dma_address(s
),
1653 .size
= sg_dma_len(s
),
1654 .direction
= direction
,
1655 .sg_call_ents
= nelems
,
1658 mapped_ents
= get_nr_mapped_entries(dev
, &ref
);
1660 if (i
>= mapped_ents
)
1663 check_sync(dev
, &ref
, false);
1666 EXPORT_SYMBOL(debug_dma_sync_sg_for_device
);
1668 static int __init
dma_debug_driver_setup(char *str
)
1672 for (i
= 0; i
< NAME_MAX_LEN
- 1; ++i
, ++str
) {
1673 current_driver_name
[i
] = *str
;
1678 if (current_driver_name
[0])
1679 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1680 current_driver_name
);
1685 __setup("dma_debug_driver=", dma_debug_driver_setup
);