| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Joerg Roedel | 3923 | 57.84% | 29 | 35.37% |
| Dan J Williams | 824 | 12.15% | 3 | 3.66% |
| FUJITA Tomonori | 410 | 6.04% | 5 | 6.10% |
| Neil Horman | 288 | 4.25% | 1 | 1.22% |
| Niklas Söderlund | 206 | 3.04% | 2 | 2.44% |
| Shuah Khan | 203 | 2.99% | 2 | 2.44% |
| David Woodhouse | 163 | 2.40% | 2 | 2.44% |
| Robin Murphy | 161 | 2.37% | 2 | 2.44% |
| Andrew Lutomirski | 135 | 1.99% | 1 | 1.22% |
| Miles Chen | 102 | 1.50% | 3 | 3.66% |
| Ingo Molnar | 59 | 0.87% | 5 | 6.10% |
| Florian Fainelli | 57 | 0.84% | 2 | 2.44% |
| Stanislaw Gruszka | 50 | 0.74% | 1 | 1.22% |
| Alexander Duyck | 43 | 0.63% | 2 | 2.44% |
| Christoph Hellwig | 40 | 0.59% | 2 | 2.44% |
| Randy Dunlap | 20 | 0.29% | 1 | 1.22% |
| Jakub Kiciński | 19 | 0.28% | 1 | 1.22% |
| Kyle McMartin | 12 | 0.18% | 1 | 1.22% |
| Krzysztof Hałasa | 11 | 0.16% | 1 | 1.22% |
| Stephen Boyd | 8 | 0.12% | 1 | 1.22% |
| Shaun Ruffell | 7 | 0.10% | 1 | 1.22% |
| Geliang Tang | 6 | 0.09% | 1 | 1.22% |
| Pankaj Gupta | 6 | 0.09% | 1 | 1.22% |
| Haggai Eran | 6 | 0.09% | 1 | 1.22% |
| Arnd Bergmann | 5 | 0.07% | 1 | 1.22% |
| Ville Syrjälä | 5 | 0.07% | 1 | 1.22% |
| Paul Gortmaker | 3 | 0.04% | 1 | 1.22% |
| Ming Lei | 3 | 0.04% | 1 | 1.22% |
| Dan Carpenter | 2 | 0.03% | 1 | 1.22% |
| André Goddard Rosa | 1 | 0.01% | 1 | 1.22% |
| Viresh Kumar | 1 | 0.01% | 1 | 1.22% |
| Laura Abbott | 1 | 0.01% | 1 | 1.22% |
| Thomas Jarosch | 1 | 0.01% | 1 | 1.22% |
| Thiago Farina | 1 | 0.01% | 1 | 1.22% |
| Sebastian Ott | 1 | 0.01% | 1 | 1.22% |
| Total | 6783 | 82 |
/* * Copyright (C) 2008 Advanced Micro Devices, Inc. * * Author: Joerg Roedel <joerg.roedel@amd.com> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. * * 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. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/sched/task_stack.h> #include <linux/scatterlist.h> #include <linux/dma-mapping.h> #include <linux/sched/task.h> #include <linux/stacktrace.h> #include <linux/dma-debug.h> #include <linux/spinlock.h> #include <linux/vmalloc.h> #include <linux/debugfs.h> #include <linux/uaccess.h> #include <linux/export.h> #include <linux/device.h> #include <linux/types.h> #include <linux/sched.h> #include <linux/ctype.h> #include <linux/list.h> #include <linux/slab.h> #include <asm/sections.h> #define HASH_SIZE 1024ULL #define HASH_FN_SHIFT 13 #define HASH_FN_MASK (HASH_SIZE - 1) /* allow architectures to override this if absolutely required */ #ifndef PREALLOC_DMA_DEBUG_ENTRIES #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16) #endif enum { dma_debug_single, dma_debug_page, dma_debug_sg, dma_debug_coherent, dma_debug_resource, }; enum map_err_types { MAP_ERR_CHECK_NOT_APPLICABLE, MAP_ERR_NOT_CHECKED, MAP_ERR_CHECKED, }; #define DMA_DEBUG_STACKTRACE_ENTRIES 5 /** * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping * @list: node on pre-allocated free_entries list * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent * @type: single, page, sg, coherent * @pfn: page frame of the start address * @offset: offset of mapping relative to pfn * @size: length of the mapping * @direction: enum dma_data_direction * @sg_call_ents: 'nents' from dma_map_sg * @sg_mapped_ents: 'mapped_ents' from dma_map_sg * @map_err_type: track whether dma_mapping_error() was checked * @stacktrace: support backtraces when a violation is detected */ struct dma_debug_entry { struct list_head list; struct device *dev; int type; unsigned long pfn; size_t offset; u64 dev_addr; u64 size; int direction; int sg_call_ents; int sg_mapped_ents; enum map_err_types map_err_type; #ifdef CONFIG_STACKTRACE struct stack_trace stacktrace; unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES]; #endif }; typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *); struct hash_bucket { struct list_head list; spinlock_t lock; } ____cacheline_aligned_in_smp; /* Hash list to save the allocated dma addresses */ static struct hash_bucket dma_entry_hash[HASH_SIZE]; /* List of pre-allocated dma_debug_entry's */ static LIST_HEAD(free_entries); /* Lock for the list above */ static DEFINE_SPINLOCK(free_entries_lock); /* Global disable flag - will be set in case of an error */ static bool global_disable __read_mostly; /* Early initialization disable flag, set at the end of dma_debug_init */ static bool dma_debug_initialized __read_mostly; static inline bool dma_debug_disabled(void) { return global_disable || !dma_debug_initialized; } /* Global error count */ static u32 error_count; /* Global error show enable*/ static u32 show_all_errors __read_mostly; /* Number of errors to show */ static u32 show_num_errors = 1; static u32 num_free_entries; static u32 min_free_entries; static u32 nr_total_entries; /* number of preallocated entries requested by kernel cmdline */ static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES; /* debugfs dentry's for the stuff above */ static struct dentry *dma_debug_dent __read_mostly; static struct dentry *global_disable_dent __read_mostly; static struct dentry *error_count_dent __read_mostly; static struct dentry *show_all_errors_dent __read_mostly; static struct dentry *show_num_errors_dent __read_mostly; static struct dentry *num_free_entries_dent __read_mostly; static struct dentry *min_free_entries_dent __read_mostly; static struct dentry *filter_dent __read_mostly; /* per-driver filter related state */ #define NAME_MAX_LEN 64 static char current_driver_name[NAME_MAX_LEN] __read_mostly; static struct device_driver *current_driver __read_mostly; static DEFINE_RWLOCK(driver_name_lock); static const char *const maperr2str[] = { [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable", [MAP_ERR_NOT_CHECKED] = "dma map error not checked", [MAP_ERR_CHECKED] = "dma map error checked", }; static const char *type2name[5] = { "single", "page", "scather-gather", "coherent", "resource" }; static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE", "DMA_FROM_DEVICE", "DMA_NONE" }; /* * The access to some variables in this macro is racy. We can't use atomic_t * here because all these variables are exported to debugfs. Some of them even * writeable. This is also the reason why a lock won't help much. But anyway, * the races are no big deal. Here is why: * * error_count: the addition is racy, but the worst thing that can happen is * that we don't count some errors * show_num_errors: the subtraction is racy. Also no big deal because in * worst case this will result in one warning more in the * system log than the user configured. This variable is * writeable via debugfs. */ static inline void dump_entry_trace(struct dma_debug_entry *entry) { #ifdef CONFIG_STACKTRACE if (entry) { pr_warning("Mapped at:\n"); print_stack_trace(&entry->stacktrace, 0); } #endif } static bool driver_filter(struct device *dev) { struct device_driver *drv; unsigned long flags; bool ret; /* driver filter off */ if (likely(!current_driver_name[0])) return true; /* driver filter on and initialized */ if (current_driver && dev && dev->driver == current_driver) return true; /* driver filter on, but we can't filter on a NULL device... */ if (!dev) return false; if (current_driver || !current_driver_name[0]) return false; /* driver filter on but not yet initialized */ drv = dev->driver; if (!drv) return false; /* lock to protect against change of current_driver_name */ read_lock_irqsave(&driver_name_lock, flags); ret = false; if (drv->name && strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) { current_driver = drv; ret = true; } read_unlock_irqrestore(&driver_name_lock, flags); return ret; } #define err_printk(dev, entry, format, arg...) do { \ error_count += 1; \ if (driver_filter(dev) && \ (show_all_errors || show_num_errors > 0)) { \ WARN(1, "%s %s: " format, \ dev ? dev_driver_string(dev) : "NULL", \ dev ? dev_name(dev) : "NULL", ## arg); \ dump_entry_trace(entry); \ } \ if (!show_all_errors && show_num_errors > 0) \ show_num_errors -= 1; \ } while (0); /* * Hash related functions * * Every DMA-API request is saved into a struct dma_debug_entry. To * have quick access to these structs they are stored into a hash. */ static int hash_fn(struct dma_debug_entry *entry) { /* * Hash function is based on the dma address. * We use bits 20-27 here as the index into the hash */ return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK; } /* * Request exclusive access to a hash bucket for a given dma_debug_entry. */ static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry, unsigned long *flags) __acquires(&dma_entry_hash[idx].lock) { int idx = hash_fn(entry); unsigned long __flags; spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags); *flags = __flags; return &dma_entry_hash[idx]; } /* * Give up exclusive access to the hash bucket */ static void put_hash_bucket(struct hash_bucket *bucket, unsigned long *flags) __releases(&bucket->lock) { unsigned long __flags = *flags; spin_unlock_irqrestore(&bucket->lock, __flags); } static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b) { return ((a->dev_addr == b->dev_addr) && (a->dev == b->dev)) ? true : false; } static bool containing_match(struct dma_debug_entry *a, struct dma_debug_entry *b) { if (a->dev != b->dev) return false; if ((b->dev_addr <= a->dev_addr) && ((b->dev_addr + b->size) >= (a->dev_addr + a->size))) return true; return false; } /* * Search a given entry in the hash bucket list */ static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket, struct dma_debug_entry *ref, match_fn match) { struct dma_debug_entry *entry, *ret = NULL; int matches = 0, match_lvl, last_lvl = -1; list_for_each_entry(entry, &bucket->list, list) { if (!match(ref, entry)) continue; /* * Some drivers map the same physical address multiple * times. Without a hardware IOMMU this results in the * same device addresses being put into the dma-debug * hash multiple times too. This can result in false * positives being reported. Therefore we implement a * best-fit algorithm here which returns the entry from * the hash which fits best to the reference value * instead of the first-fit. */ matches += 1; match_lvl = 0; entry->size == ref->size ? ++match_lvl : 0; entry->type == ref->type ? ++match_lvl : 0; entry->direction == ref->direction ? ++match_lvl : 0; entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0; if (match_lvl == 4) { /* perfect-fit - return the result */ return entry; } else if (match_lvl > last_lvl) { /* * We found an entry that fits better then the * previous one or it is the 1st match. */ last_lvl = match_lvl; ret = entry; } } /* * If we have multiple matches but no perfect-fit, just return * NULL. */ ret = (matches == 1) ? ret : NULL; return ret; } static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket, struct dma_debug_entry *ref) { return __hash_bucket_find(bucket, ref, exact_match); } static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket, struct dma_debug_entry *ref, unsigned long *flags) { unsigned int max_range = dma_get_max_seg_size(ref->dev); struct dma_debug_entry *entry, index = *ref; unsigned int range = 0; while (range <= max_range) { entry = __hash_bucket_find(*bucket, ref, containing_match); if (entry) return entry; /* * Nothing found, go back a hash bucket */ put_hash_bucket(*bucket, flags); range += (1 << HASH_FN_SHIFT); index.dev_addr -= (1 << HASH_FN_SHIFT); *bucket = get_hash_bucket(&index, flags); } return NULL; } /* * Add an entry to a hash bucket */ static void hash_bucket_add(struct hash_bucket *bucket, struct dma_debug_entry *entry) { list_add_tail(&entry->list, &bucket->list); } /* * Remove entry from a hash bucket list */ static void hash_bucket_del(struct dma_debug_entry *entry) { list_del(&entry->list); } static unsigned long long phys_addr(struct dma_debug_entry *entry) { if (entry->type == dma_debug_resource) return __pfn_to_phys(entry->pfn) + entry->offset; return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset; } /* * Dump mapping entries for debugging purposes */ void debug_dma_dump_mappings(struct device *dev) { int idx; for (idx = 0; idx < HASH_SIZE; idx++) { struct hash_bucket *bucket = &dma_entry_hash[idx]; struct dma_debug_entry *entry; unsigned long flags; spin_lock_irqsave(&bucket->lock, flags); list_for_each_entry(entry, &bucket->list, list) { if (!dev || dev == entry->dev) { dev_info(entry->dev, "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n", type2name[entry->type], idx, phys_addr(entry), entry->pfn, entry->dev_addr, entry->size, dir2name[entry->direction], maperr2str[entry->map_err_type]); } } spin_unlock_irqrestore(&bucket->lock, flags); } } /* * For each mapping (initial cacheline in the case of * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a * scatterlist, or the cacheline specified in dma_map_single) insert * into this tree using the cacheline as the key. At * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry. If * the entry already exists at insertion time add a tag as a reference * count for the overlapping mappings. For now, the overlap tracking * just ensures that 'unmaps' balance 'maps' before marking the * cacheline idle, but we should also be flagging overlaps as an API * violation. * * Memory usage is mostly constrained by the maximum number of available * dma-debug entries in that we need a free dma_debug_entry before * inserting into the tree. In the case of dma_map_page and * dma_alloc_coherent there is only one dma_debug_entry and one * dma_active_cacheline entry to track per event. dma_map_sg(), on the * other hand, consumes a single dma_debug_entry, but inserts 'nents' * entries into the tree. * * At any time debug_dma_assert_idle() can be called to trigger a * warning if any cachelines in the given page are in the active set. */ static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT); static DEFINE_SPINLOCK(radix_lock); #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1) #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT) #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT) static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry) { return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) + (entry->offset >> L1_CACHE_SHIFT); } static int active_cacheline_read_overlap(phys_addr_t cln) { int overlap = 0, i; for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--) if (radix_tree_tag_get(&dma_active_cacheline, cln, i)) overlap |= 1 << i; return overlap; } static int active_cacheline_set_overlap(phys_addr_t cln, int overlap) { int i; if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0) return overlap; for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--) if (overlap & 1 << i) radix_tree_tag_set(&dma_active_cacheline, cln, i); else radix_tree_tag_clear(&dma_active_cacheline, cln, i); return overlap; } static void active_cacheline_inc_overlap(phys_addr_t cln) { int overlap = active_cacheline_read_overlap(cln); overlap = active_cacheline_set_overlap(cln, ++overlap); /* If we overflowed the overlap counter then we're potentially * leaking dma-mappings. Otherwise, if maps and unmaps are * balanced then this overflow may cause false negatives in * debug_dma_assert_idle() as the cacheline may be marked idle * prematurely. */ WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP, "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n", ACTIVE_CACHELINE_MAX_OVERLAP, &cln); } static int active_cacheline_dec_overlap(phys_addr_t cln) { int overlap = active_cacheline_read_overlap(cln); return active_cacheline_set_overlap(cln, --overlap); } static int active_cacheline_insert(struct dma_debug_entry *entry) { phys_addr_t cln = to_cacheline_number(entry); unsigned long flags; int rc; /* If the device is not writing memory then we don't have any * concerns about the cpu consuming stale data. This mitigates * legitimate usages of overlapping mappings. */ if (entry->direction == DMA_TO_DEVICE) return 0; spin_lock_irqsave(&radix_lock, flags); rc = radix_tree_insert(&dma_active_cacheline, cln, entry); if (rc == -EEXIST) active_cacheline_inc_overlap(cln); spin_unlock_irqrestore(&radix_lock, flags); return rc; } static void active_cacheline_remove(struct dma_debug_entry *entry) { phys_addr_t cln = to_cacheline_number(entry); unsigned long flags; /* ...mirror the insert case */ if (entry->direction == DMA_TO_DEVICE) return; spin_lock_irqsave(&radix_lock, flags); /* since we are counting overlaps the final put of the * cacheline will occur when the overlap count is 0. * active_cacheline_dec_overlap() returns -1 in that case */ if (active_cacheline_dec_overlap(cln) < 0) radix_tree_delete(&dma_active_cacheline, cln); spin_unlock_irqrestore(&radix_lock, flags); } /** * debug_dma_assert_idle() - assert that a page is not undergoing dma * @page: page to lookup in the dma_active_cacheline tree * * Place a call to this routine in cases where the cpu touching the page * before the dma completes (page is dma_unmapped) will lead to data * corruption. */ void debug_dma_assert_idle(struct page *page) { static struct dma_debug_entry *ents[CACHELINES_PER_PAGE]; struct dma_debug_entry *entry = NULL; void **results = (void **) &ents; unsigned int nents, i; unsigned long flags; phys_addr_t cln; if (dma_debug_disabled()) return; if (!page) return; cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT; spin_lock_irqsave(&radix_lock, flags); nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln, CACHELINES_PER_PAGE); for (i = 0; i < nents; i++) { phys_addr_t ent_cln = to_cacheline_number(ents[i]); if (ent_cln == cln) { entry = ents[i]; break; } else if (ent_cln >= cln + CACHELINES_PER_PAGE) break; } spin_unlock_irqrestore(&radix_lock, flags); if (!entry) return; cln = to_cacheline_number(entry); err_printk(entry->dev, entry, "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n", &cln); } /* * Wrapper function for adding an entry to the hash. * This function takes care of locking itself. */ static void add_dma_entry(struct dma_debug_entry *entry) { struct hash_bucket *bucket; unsigned long flags; int rc; bucket = get_hash_bucket(entry, &flags); hash_bucket_add(bucket, entry); put_hash_bucket(bucket, &flags); rc = active_cacheline_insert(entry); if (rc == -ENOMEM) { pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n"); global_disable = true; } /* TODO: report -EEXIST errors here as overlapping mappings are * not supported by the DMA API */ } static struct dma_debug_entry *__dma_entry_alloc(void) { struct dma_debug_entry *entry; entry = list_entry(free_entries.next, struct dma_debug_entry, list); list_del(&entry->list); memset(entry, 0, sizeof(*entry)); num_free_entries -= 1; if (num_free_entries < min_free_entries) min_free_entries = num_free_entries; return entry; } /* struct dma_entry allocator * * The next two functions implement the allocator for * struct dma_debug_entries. */ static struct dma_debug_entry *dma_entry_alloc(void) { struct dma_debug_entry *entry; unsigned long flags; spin_lock_irqsave(&free_entries_lock, flags); if (list_empty(&free_entries)) { global_disable = true; spin_unlock_irqrestore(&free_entries_lock, flags); pr_err("DMA-API: debugging out of memory - disabling\n"); return NULL; } entry = __dma_entry_alloc(); spin_unlock_irqrestore(&free_entries_lock, flags); #ifdef CONFIG_STACKTRACE entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES; entry->stacktrace.entries = entry->st_entries; entry->stacktrace.skip = 2; save_stack_trace(&entry->stacktrace); #endif return entry; } static void dma_entry_free(struct dma_debug_entry *entry) { unsigned long flags; active_cacheline_remove(entry); /* * add to beginning of the list - this way the entries are * more likely cache hot when they are reallocated. */ spin_lock_irqsave(&free_entries_lock, flags); list_add(&entry->list, &free_entries); num_free_entries += 1; spin_unlock_irqrestore(&free_entries_lock, flags); } int dma_debug_resize_entries(u32 num_entries) { int i, delta, ret = 0; unsigned long flags; struct dma_debug_entry *entry; LIST_HEAD(tmp); spin_lock_irqsave(&free_entries_lock, flags); if (nr_total_entries < num_entries) { delta = num_entries - nr_total_entries; spin_unlock_irqrestore(&free_entries_lock, flags); for (i = 0; i < delta; i++) { entry = kzalloc(sizeof(*entry), GFP_KERNEL); if (!entry) break; list_add_tail(&entry->list, &tmp); } spin_lock_irqsave(&free_entries_lock, flags); list_splice(&tmp, &free_entries); nr_total_entries += i; num_free_entries += i; } else { delta = nr_total_entries - num_entries; for (i = 0; i < delta && !list_empty(&free_entries); i++) { entry = __dma_entry_alloc(); kfree(entry); } nr_total_entries -= i; } if (nr_total_entries != num_entries) ret = 1; spin_unlock_irqrestore(&free_entries_lock, flags); return ret; } /* * DMA-API debugging init code * * The init code does two things: * 1. Initialize core data structures * 2. Preallocate a given number of dma_debug_entry structs */ static int prealloc_memory(u32 num_entries) { struct dma_debug_entry *entry, *next_entry; int i; for (i = 0; i < num_entries; ++i) { entry = kzalloc(sizeof(*entry), GFP_KERNEL); if (!entry) goto out_err; list_add_tail(&entry->list, &free_entries); } num_free_entries = num_entries; min_free_entries = num_entries; pr_info("DMA-API: preallocated %d debug entries\n", num_entries); return 0; out_err: list_for_each_entry_safe(entry, next_entry, &free_entries, list) { list_del(&entry->list); kfree(entry); } return -ENOMEM; } static ssize_t filter_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { char buf[NAME_MAX_LEN + 1]; unsigned long flags; int len; if (!current_driver_name[0]) return 0; /* * We can't copy to userspace directly because current_driver_name can * only be read under the driver_name_lock with irqs disabled. So * create a temporary copy first. */ read_lock_irqsave(&driver_name_lock, flags); len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name); read_unlock_irqrestore(&driver_name_lock, flags); return simple_read_from_buffer(user_buf, count, ppos, buf, len); } static ssize_t filter_write(struct file *file, const char __user *userbuf, size_t count, loff_t *ppos) { char buf[NAME_MAX_LEN]; unsigned long flags; size_t len; int i; /* * We can't copy from userspace directly. Access to * current_driver_name is protected with a write_lock with irqs * disabled. Since copy_from_user can fault and may sleep we * need to copy to temporary buffer first */ len = min(count, (size_t)(NAME_MAX_LEN - 1)); if (copy_from_user(buf, userbuf, len)) return -EFAULT; buf[len] = 0; write_lock_irqsave(&driver_name_lock, flags); /* * Now handle the string we got from userspace very carefully. * The rules are: * - only use the first token we got * - token delimiter is everything looking like a space * character (' ', '\n', '\t' ...) * */ if (!isalnum(buf[0])) { /* * If the first character userspace gave us is not * alphanumerical then assume the filter should be * switched off. */ if (current_driver_name[0]) pr_info("DMA-API: switching off dma-debug driver filter\n"); current_driver_name[0] = 0; current_driver = NULL; goto out_unlock; } /* * Now parse out the first token and use it as the name for the * driver to filter for. */ for (i = 0; i < NAME_MAX_LEN - 1; ++i) { current_driver_name[i] = buf[i]; if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0) break; } current_driver_name[i] = 0; current_driver = NULL; pr_info("DMA-API: enable driver filter for driver [%s]\n", current_driver_name); out_unlock: write_unlock_irqrestore(&driver_name_lock, flags); return count; } static const struct file_operations filter_fops = { .read = filter_read, .write = filter_write, .llseek = default_llseek, }; static int dma_debug_fs_init(void) { dma_debug_dent = debugfs_create_dir("dma-api", NULL); if (!dma_debug_dent) { pr_err("DMA-API: can not create debugfs directory\n"); return -ENOMEM; } global_disable_dent = debugfs_create_bool("disabled", 0444, dma_debug_dent, &global_disable); if (!global_disable_dent) goto out_err; error_count_dent = debugfs_create_u32("error_count", 0444, dma_debug_dent, &error_count); if (!error_count_dent) goto out_err; show_all_errors_dent = debugfs_create_u32("all_errors", 0644, dma_debug_dent, &show_all_errors); if (!show_all_errors_dent) goto out_err; show_num_errors_dent = debugfs_create_u32("num_errors", 0644, dma_debug_dent, &show_num_errors); if (!show_num_errors_dent) goto out_err; num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444, dma_debug_dent, &num_free_entries); if (!num_free_entries_dent) goto out_err; min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444, dma_debug_dent, &min_free_entries); if (!min_free_entries_dent) goto out_err; filter_dent = debugfs_create_file("driver_filter", 0644, dma_debug_dent, NULL, &filter_fops); if (!filter_dent) goto out_err; return 0; out_err: debugfs_remove_recursive(dma_debug_dent); return -ENOMEM; } static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry) { struct dma_debug_entry *entry; unsigned long flags; int count = 0, i; for (i = 0; i < HASH_SIZE; ++i) { spin_lock_irqsave(&dma_entry_hash[i].lock, flags); list_for_each_entry(entry, &dma_entry_hash[i].list, list) { if (entry->dev == dev) { count += 1; *out_entry = entry; } } spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags); } return count; } static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data) { struct device *dev = data; struct dma_debug_entry *uninitialized_var(entry); int count; if (dma_debug_disabled()) return 0; switch (action) { case BUS_NOTIFY_UNBOUND_DRIVER: count = device_dma_allocations(dev, &entry); if (count == 0) break; err_printk(dev, entry, "DMA-API: device driver has pending " "DMA allocations while released from device " "[count=%d]\n" "One of leaked entries details: " "[device address=0x%016llx] [size=%llu bytes] " "[mapped with %s] [mapped as %s]\n", count, entry->dev_addr, entry->size, dir2name[entry->direction], type2name[entry->type]); break; default: break; } return 0; } void dma_debug_add_bus(struct bus_type *bus) { struct notifier_block *nb; if (dma_debug_disabled()) return; nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL); if (nb == NULL) { pr_err("dma_debug_add_bus: out of memory\n"); return; } nb->notifier_call = dma_debug_device_change; bus_register_notifier(bus, nb); } static int dma_debug_init(void) { int i; /* Do not use dma_debug_initialized here, since we really want to be * called to set dma_debug_initialized */ if (global_disable) return 0; for (i = 0; i < HASH_SIZE; ++i) { INIT_LIST_HEAD(&dma_entry_hash[i].list); spin_lock_init(&dma_entry_hash[i].lock); } if (dma_debug_fs_init() != 0) { pr_err("DMA-API: error creating debugfs entries - disabling\n"); global_disable = true; return 0; } if (prealloc_memory(nr_prealloc_entries) != 0) { pr_err("DMA-API: debugging out of memory error - disabled\n"); global_disable = true; return 0; } nr_total_entries = num_free_entries; dma_debug_initialized = true; pr_info("DMA-API: debugging enabled by kernel config\n"); return 0; } core_initcall(dma_debug_init); static __init int dma_debug_cmdline(char *str) { if (!str) return -EINVAL; if (strncmp(str, "off", 3) == 0) { pr_info("DMA-API: debugging disabled on kernel command line\n"); global_disable = true; } return 0; } static __init int dma_debug_entries_cmdline(char *str) { if (!str) return -EINVAL; if (!get_option(&str, &nr_prealloc_entries)) nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES; return 0; } __setup("dma_debug=", dma_debug_cmdline); __setup("dma_debug_entries=", dma_debug_entries_cmdline); static void check_unmap(struct dma_debug_entry *ref) { struct dma_debug_entry *entry; struct hash_bucket *bucket; unsigned long flags; bucket = get_hash_bucket(ref, &flags); entry = bucket_find_exact(bucket, ref); if (!entry) { /* must drop lock before calling dma_mapping_error */ put_hash_bucket(bucket, &flags); if (dma_mapping_error(ref->dev, ref->dev_addr)) { err_printk(ref->dev, NULL, "DMA-API: device driver tries to free an " "invalid DMA memory address\n"); } else { err_printk(ref->dev, NULL, "DMA-API: device driver tries to free DMA " "memory it has not allocated [device " "address=0x%016llx] [size=%llu bytes]\n", ref->dev_addr, ref->size); } return; } if (ref->size != entry->size) { err_printk(ref->dev, entry, "DMA-API: device driver frees " "DMA memory with different size " "[device address=0x%016llx] [map size=%llu bytes] " "[unmap size=%llu bytes]\n", ref->dev_addr, entry->size, ref->size); } if (ref->type != entry->type) { err_printk(ref->dev, entry, "DMA-API: device driver frees " "DMA memory with wrong function " "[device address=0x%016llx] [size=%llu bytes] " "[mapped as %s] [unmapped as %s]\n", ref->dev_addr, ref->size, type2name[entry->type], type2name[ref->type]); } else if ((entry->type == dma_debug_coherent) && (phys_addr(ref) != phys_addr(entry))) { err_printk(ref->dev, entry, "DMA-API: device driver frees " "DMA memory with different CPU address " "[device address=0x%016llx] [size=%llu bytes] " "[cpu alloc address=0x%016llx] " "[cpu free address=0x%016llx]", ref->dev_addr, ref->size, phys_addr(entry), phys_addr(ref)); } if (ref->sg_call_ents && ref->type == dma_debug_sg && ref->sg_call_ents != entry->sg_call_ents) { err_printk(ref->dev, entry, "DMA-API: device driver frees " "DMA sg list with different entry count " "[map count=%d] [unmap count=%d]\n", entry->sg_call_ents, ref->sg_call_ents); } /* * This may be no bug in reality - but most implementations of the * DMA API don't handle this properly, so check for it here */ if (ref->direction != entry->direction) { err_printk(ref->dev, entry, "DMA-API: device driver frees " "DMA memory with different direction " "[device address=0x%016llx] [size=%llu bytes] " "[mapped with %s] [unmapped with %s]\n", ref->dev_addr, ref->size, dir2name[entry->direction], dir2name[ref->direction]); } /* * Drivers should use dma_mapping_error() to check the returned * addresses of dma_map_single() and dma_map_page(). * If not, print this warning message. See Documentation/DMA-API.txt. */ if (entry->map_err_type == MAP_ERR_NOT_CHECKED) { err_printk(ref->dev, entry, "DMA-API: device driver failed to check map error" "[device address=0x%016llx] [size=%llu bytes] " "[mapped as %s]", ref->dev_addr, ref->size, type2name[entry->type]); } hash_bucket_del(entry); dma_entry_free(entry); put_hash_bucket(bucket, &flags); } static void check_for_stack(struct device *dev, struct page *page, size_t offset) { void *addr; struct vm_struct *stack_vm_area = task_stack_vm_area(current); if (!stack_vm_area) { /* Stack is direct-mapped. */ if (PageHighMem(page)) return; addr = page_address(page) + offset; if (object_is_on_stack(addr)) err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [addr=%p]\n", addr); } else { /* Stack is vmalloced. */ int i; for (i = 0; i < stack_vm_area->nr_pages; i++) { if (page != stack_vm_area->pages[i]) continue; addr = (u8 *)current->stack + i * PAGE_SIZE + offset; err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [probable addr=%p]\n", addr); break; } } } static inline bool overlap(void *addr, unsigned long len, void *start, void *end) { unsigned long a1 = (unsigned long)addr; unsigned long b1 = a1 + len; unsigned long a2 = (unsigned long)start; unsigned long b2 = (unsigned long)end; return !(b1 <= a2 || a1 >= b2); } static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len) { if (overlap(addr, len, _stext, _etext) || overlap(addr, len, __start_rodata, __end_rodata)) err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len); } static void check_sync(struct device *dev, struct dma_debug_entry *ref, bool to_cpu) { struct dma_debug_entry *entry; struct hash_bucket *bucket; unsigned long flags; bucket = get_hash_bucket(ref, &flags); entry = bucket_find_contain(&bucket, ref, &flags); if (!entry) { err_printk(dev, NULL, "DMA-API: device driver tries " "to sync DMA memory it has not allocated " "[device address=0x%016llx] [size=%llu bytes]\n", (unsigned long long)ref->dev_addr, ref->size); goto out; } if (ref->size > entry->size) { err_printk(dev, entry, "DMA-API: device driver syncs" " DMA memory outside allocated range " "[device address=0x%016llx] " "[allocation size=%llu bytes] " "[sync offset+size=%llu]\n", entry->dev_addr, entry->size, ref->size); } if (entry->direction == DMA_BIDIRECTIONAL) goto out; if (ref->direction != entry->direction) { err_printk(dev, entry, "DMA-API: device driver syncs " "DMA memory with different direction " "[device address=0x%016llx] [size=%llu bytes] " "[mapped with %s] [synced with %s]\n", (unsigned long long)ref->dev_addr, entry->size, dir2name[entry->direction], dir2name[ref->direction]); } if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) && !(ref->direction == DMA_TO_DEVICE)) err_printk(dev, entry, "DMA-API: device driver syncs " "device read-only DMA memory for cpu " "[device address=0x%016llx] [size=%llu bytes] " "[mapped with %s] [synced with %s]\n", (unsigned long long)ref->dev_addr, entry->size, dir2name[entry->direction], dir2name[ref->direction]); if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) && !(ref->direction == DMA_FROM_DEVICE)) err_printk(dev, entry, "DMA-API: device driver syncs " "device write-only DMA memory to device " "[device address=0x%016llx] [size=%llu bytes] " "[mapped with %s] [synced with %s]\n", (unsigned long long)ref->dev_addr, entry->size, dir2name[entry->direction], dir2name[ref->direction]); if (ref->sg_call_ents && ref->type == dma_debug_sg && ref->sg_call_ents != entry->sg_call_ents) { err_printk(ref->dev, entry, "DMA-API: device driver syncs " "DMA sg list with different entry count " "[map count=%d] [sync count=%d]\n", entry->sg_call_ents, ref->sg_call_ents); } out: put_hash_bucket(bucket, &flags); } static void check_sg_segment(struct device *dev, struct scatterlist *sg) { #ifdef CONFIG_DMA_API_DEBUG_SG unsigned int max_seg = dma_get_max_seg_size(dev); u64 start, end, boundary = dma_get_seg_boundary(dev); /* * Either the driver forgot to set dma_parms appropriately, or * whoever generated the list forgot to check them. */ if (sg->length > max_seg) err_printk(dev, NULL, "DMA-API: mapping sg segment longer than device claims to support [len=%u] [max=%u]\n", sg->length, max_seg); /* * In some cases this could potentially be the DMA API * implementation's fault, but it would usually imply that * the scatterlist was built inappropriately to begin with. */ start = sg_dma_address(sg); end = start + sg_dma_len(sg) - 1; if ((start ^ end) & ~boundary) err_printk(dev, NULL, "DMA-API: mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n", start, end, boundary); #endif } void debug_dma_map_page(struct device *dev, struct page *page, size_t offset, size_t size, int direction, dma_addr_t dma_addr, bool map_single) { struct dma_debug_entry *entry; if (unlikely(dma_debug_disabled())) return; if (dma_mapping_error(dev, dma_addr)) return; entry = dma_entry_alloc(); if (!entry) return; entry->dev = dev; entry->type = dma_debug_page; entry->pfn = page_to_pfn(page); entry->offset = offset, entry->dev_addr = dma_addr; entry->size = size; entry->direction = direction; entry->map_err_type = MAP_ERR_NOT_CHECKED; if (map_single) entry->type = dma_debug_single; check_for_stack(dev, page, offset); if (!PageHighMem(page)) { void *addr = page_address(page) + offset; check_for_illegal_area(dev, addr, size); } add_dma_entry(entry); } EXPORT_SYMBOL(debug_dma_map_page); void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr) { struct dma_debug_entry ref; struct dma_debug_entry *entry; struct hash_bucket *bucket; unsigned long flags; if (unlikely(dma_debug_disabled())) return; ref.dev = dev; ref.dev_addr = dma_addr; bucket = get_hash_bucket(&ref, &flags); list_for_each_entry(entry, &bucket->list, list) { if (!exact_match(&ref, entry)) continue; /* * The same physical address can be mapped multiple * times. Without a hardware IOMMU this results in the * same device addresses being put into the dma-debug * hash multiple times too. This can result in false * positives being reported. Therefore we implement a * best-fit algorithm here which updates the first entry * from the hash which fits the reference value and is * not currently listed as being checked. */ if (entry->map_err_type == MAP_ERR_NOT_CHECKED) { entry->map_err_type = MAP_ERR_CHECKED; break; } } put_hash_bucket(bucket, &flags); } EXPORT_SYMBOL(debug_dma_mapping_error); void debug_dma_unmap_page(struct device *dev, dma_addr_t addr, size_t size, int direction, bool map_single) { struct dma_debug_entry ref = { .type = dma_debug_page, .dev = dev, .dev_addr = addr, .size = size, .direction = direction, }; if (unlikely(dma_debug_disabled())) return; if (map_single) ref.type = dma_debug_single; check_unmap(&ref); } EXPORT_SYMBOL(debug_dma_unmap_page); void debug_dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, int mapped_ents, int direction) { struct dma_debug_entry *entry; struct scatterlist *s; int i; if (unlikely(dma_debug_disabled())) return; for_each_sg(sg, s, mapped_ents, i) { entry = dma_entry_alloc(); if (!entry) return; entry->type = dma_debug_sg; entry->dev = dev; entry->pfn = page_to_pfn(sg_page(s)); entry->offset = s->offset, entry->size = sg_dma_len(s); entry->dev_addr = sg_dma_address(s); entry->direction = direction; entry->sg_call_ents = nents; entry->sg_mapped_ents = mapped_ents; check_for_stack(dev, sg_page(s), s->offset); if (!PageHighMem(sg_page(s))) { check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s)); } check_sg_segment(dev, s); add_dma_entry(entry); } } EXPORT_SYMBOL(debug_dma_map_sg); static int get_nr_mapped_entries(struct device *dev, struct dma_debug_entry *ref) { struct dma_debug_entry *entry; struct hash_bucket *bucket; unsigned long flags; int mapped_ents; bucket = get_hash_bucket(ref, &flags); entry = bucket_find_exact(bucket, ref); mapped_ents = 0; if (entry) mapped_ents = entry->sg_mapped_ents; put_hash_bucket(bucket, &flags); return mapped_ents; } void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist, int nelems, int dir) { struct scatterlist *s; int mapped_ents = 0, i; if (unlikely(dma_debug_disabled())) return; for_each_sg(sglist, s, nelems, i) { struct dma_debug_entry ref = { .type = dma_debug_sg, .dev = dev, .pfn = page_to_pfn(sg_page(s)), .offset = s->offset, .dev_addr = sg_dma_address(s), .size = sg_dma_len(s), .direction = dir, .sg_call_ents = nelems, }; if (mapped_ents && i >= mapped_ents) break; if (!i) mapped_ents = get_nr_mapped_entries(dev, &ref); check_unmap(&ref); } } EXPORT_SYMBOL(debug_dma_unmap_sg); void debug_dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t dma_addr, void *virt) { struct dma_debug_entry *entry; if (unlikely(dma_debug_disabled())) return; if (unlikely(virt == NULL)) return; /* handle vmalloc and linear addresses */ if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt)) return; entry = dma_entry_alloc(); if (!entry) return; entry->type = dma_debug_coherent; entry->dev = dev; entry->offset = offset_in_page(virt); entry->size = size; entry->dev_addr = dma_addr; entry->direction = DMA_BIDIRECTIONAL; if (is_vmalloc_addr(virt)) entry->pfn = vmalloc_to_pfn(virt); else entry->pfn = page_to_pfn(virt_to_page(virt)); add_dma_entry(entry); } EXPORT_SYMBOL(debug_dma_alloc_coherent); void debug_dma_free_coherent(struct device *dev, size_t size, void *virt, dma_addr_t addr) { struct dma_debug_entry ref = { .type = dma_debug_coherent, .dev = dev, .offset = offset_in_page(virt), .dev_addr = addr, .size = size, .direction = DMA_BIDIRECTIONAL, }; /* handle vmalloc and linear addresses */ if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt)) return; if (is_vmalloc_addr(virt)) ref.pfn = vmalloc_to_pfn(virt); else ref.pfn = page_to_pfn(virt_to_page(virt)); if (unlikely(dma_debug_disabled())) return; check_unmap(&ref); } EXPORT_SYMBOL(debug_dma_free_coherent); void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size, int direction, dma_addr_t dma_addr) { struct dma_debug_entry *entry; if (unlikely(dma_debug_disabled())) return; entry = dma_entry_alloc(); if (!entry) return; entry->type = dma_debug_resource; entry->dev = dev; entry->pfn = PHYS_PFN(addr); entry->offset = offset_in_page(addr); entry->size = size; entry->dev_addr = dma_addr; entry->direction = direction; entry->map_err_type = MAP_ERR_NOT_CHECKED; add_dma_entry(entry); } EXPORT_SYMBOL(debug_dma_map_resource); void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr, size_t size, int direction) { struct dma_debug_entry ref = { .type = dma_debug_resource, .dev = dev, .dev_addr = dma_addr, .size = size, .direction = direction, }; if (unlikely(dma_debug_disabled())) return; check_unmap(&ref); } EXPORT_SYMBOL(debug_dma_unmap_resource); void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle, size_t size, int direction) { struct dma_debug_entry ref; if (unlikely(dma_debug_disabled())) return; ref.type = dma_debug_single; ref.dev = dev; ref.dev_addr = dma_handle; ref.size = size; ref.direction = direction; ref.sg_call_ents = 0; check_sync(dev, &ref, true); } EXPORT_SYMBOL(debug_dma_sync_single_for_cpu); void debug_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle, size_t size, int direction) { struct dma_debug_entry ref; if (unlikely(dma_debug_disabled())) return; ref.type = dma_debug_single; ref.dev = dev; ref.dev_addr = dma_handle; ref.size = size; ref.direction = direction; ref.sg_call_ents = 0; check_sync(dev, &ref, false); } EXPORT_SYMBOL(debug_dma_sync_single_for_device); void debug_dma_sync_single_range_for_cpu(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, int direction) { struct dma_debug_entry ref; if (unlikely(dma_debug_disabled())) return; ref.type = dma_debug_single; ref.dev = dev; ref.dev_addr = dma_handle; ref.size = offset + size; ref.direction = direction; ref.sg_call_ents = 0; check_sync(dev, &ref, true); } EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu); void debug_dma_sync_single_range_for_device(struct device *dev, dma_addr_t dma_handle, unsigned long offset, size_t size, int direction) { struct dma_debug_entry ref; if (unlikely(dma_debug_disabled())) return; ref.type = dma_debug_single; ref.dev = dev; ref.dev_addr = dma_handle; ref.size = offset + size; ref.direction = direction; ref.sg_call_ents = 0; check_sync(dev, &ref, false); } EXPORT_SYMBOL(debug_dma_sync_single_range_for_device); void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nelems, int direction) { struct scatterlist *s; int mapped_ents = 0, i; if (unlikely(dma_debug_disabled())) return; for_each_sg(sg, s, nelems, i) { struct dma_debug_entry ref = { .type = dma_debug_sg, .dev = dev, .pfn = page_to_pfn(sg_page(s)), .offset = s->offset, .dev_addr = sg_dma_address(s), .size = sg_dma_len(s), .direction = direction, .sg_call_ents = nelems, }; if (!i) mapped_ents = get_nr_mapped_entries(dev, &ref); if (i >= mapped_ents) break; check_sync(dev, &ref, true); } } EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu); void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nelems, int direction) { struct scatterlist *s; int mapped_ents = 0, i; if (unlikely(dma_debug_disabled())) return; for_each_sg(sg, s, nelems, i) { struct dma_debug_entry ref = { .type = dma_debug_sg, .dev = dev, .pfn = page_to_pfn(sg_page(s)), .offset = s->offset, .dev_addr = sg_dma_address(s), .size = sg_dma_len(s), .direction = direction, .sg_call_ents = nelems, }; if (!i) mapped_ents = get_nr_mapped_entries(dev, &ref); if (i >= mapped_ents) break; check_sync(dev, &ref, false); } } EXPORT_SYMBOL(debug_dma_sync_sg_for_device); static int __init dma_debug_driver_setup(char *str) { int i; for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) { current_driver_name[i] = *str; if (*str == 0) break; } if (current_driver_name[0]) pr_info("DMA-API: enable driver filter for driver [%s]\n", current_driver_name); return 1; } __setup("dma_debug_driver=", dma_debug_driver_setup);
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with Cregit http://github.com/cregit/cregit
Version 2.0-RC1