dma-debug: add core checking functions
Impact: add functions to check on dma unmap and sync Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel
parent
788dcfa6f1
commit
2d62ece14f
188
lib/dma-debug.c
188
lib/dma-debug.c
@ -17,10 +17,13 @@
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/dma-mapping.h>
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#include <linux/dma-debug.h>
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#include <linux/spinlock.h>
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#include <linux/debugfs.h>
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#include <linux/device.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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@ -50,7 +53,7 @@ struct dma_debug_entry {
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struct hash_bucket {
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struct list_head list;
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spinlock_t lock;
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} __cacheline_aligned_in_smp;
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} ____cacheline_aligned_in_smp;
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/* Hash list to save the allocated dma addresses */
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static struct hash_bucket dma_entry_hash[HASH_SIZE];
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@ -85,6 +88,36 @@ static struct dentry *show_num_errors_dent __read_mostly;
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static struct dentry *num_free_entries_dent __read_mostly;
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static struct dentry *min_free_entries_dent __read_mostly;
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static const char *type2name[4] = { "single", "page",
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"scather-gather", "coherent" };
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static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
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"DMA_FROM_DEVICE", "DMA_NONE" };
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/*
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* The access to some variables in this macro is racy. We can't use atomic_t
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* here because all these variables are exported to debugfs. Some of them even
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* writeable. This is also the reason why a lock won't help much. But anyway,
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* the races are no big deal. Here is why:
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*
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* error_count: the addition is racy, but the worst thing that can happen is
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* that we don't count some errors
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* show_num_errors: the subtraction is racy. Also no big deal because in
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* worst case this will result in one warning more in the
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* system log than the user configured. This variable is
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* writeable via debugfs.
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*/
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#define err_printk(dev, format, arg...) do { \
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error_count += 1; \
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if (show_all_errors || show_num_errors > 0) { \
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WARN(1, "%s %s: " format, \
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dev_driver_string(dev), \
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dev_name(dev) , ## arg); \
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} \
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if (!show_all_errors && show_num_errors > 0) \
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show_num_errors -= 1; \
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} while (0);
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/*
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* Hash related functions
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*
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@ -380,3 +413,156 @@ static __init int dma_debug_entries_cmdline(char *str)
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__setup("dma_debug=", dma_debug_cmdline);
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__setup("dma_debug_entries=", dma_debug_entries_cmdline);
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static void check_unmap(struct dma_debug_entry *ref)
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{
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struct dma_debug_entry *entry;
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struct hash_bucket *bucket;
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unsigned long flags;
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if (dma_mapping_error(ref->dev, ref->dev_addr))
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return;
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bucket = get_hash_bucket(ref, &flags);
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entry = hash_bucket_find(bucket, ref);
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if (!entry) {
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err_printk(ref->dev, "DMA-API: device driver tries "
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"to free DMA memory it has not allocated "
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"[device address=0x%016llx] [size=%llu bytes]\n",
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ref->dev_addr, ref->size);
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goto out;
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}
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if (ref->size != entry->size) {
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err_printk(ref->dev, "DMA-API: device driver frees "
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"DMA memory with different size "
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"[device address=0x%016llx] [map size=%llu bytes] "
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"[unmap size=%llu bytes]\n",
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ref->dev_addr, entry->size, ref->size);
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}
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if (ref->type != entry->type) {
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err_printk(ref->dev, "DMA-API: device driver frees "
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"DMA memory with wrong function "
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"[device address=0x%016llx] [size=%llu bytes] "
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"[mapped as %s] [unmapped as %s]\n",
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ref->dev_addr, ref->size,
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type2name[entry->type], type2name[ref->type]);
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} else if ((entry->type == dma_debug_coherent) &&
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(ref->paddr != entry->paddr)) {
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err_printk(ref->dev, "DMA-API: device driver frees "
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"DMA memory with different CPU address "
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"[device address=0x%016llx] [size=%llu bytes] "
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"[cpu alloc address=%p] [cpu free address=%p]",
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ref->dev_addr, ref->size,
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(void *)entry->paddr, (void *)ref->paddr);
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}
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if (ref->sg_call_ents && ref->type == dma_debug_sg &&
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ref->sg_call_ents != entry->sg_call_ents) {
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err_printk(ref->dev, "DMA-API: device driver frees "
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"DMA sg list with different entry count "
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"[map count=%d] [unmap count=%d]\n",
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entry->sg_call_ents, ref->sg_call_ents);
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}
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/*
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* This may be no bug in reality - but most implementations of the
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* DMA API don't handle this properly, so check for it here
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*/
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if (ref->direction != entry->direction) {
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err_printk(ref->dev, "DMA-API: device driver frees "
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"DMA memory with different direction "
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"[device address=0x%016llx] [size=%llu bytes] "
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"[mapped with %s] [unmapped with %s]\n",
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ref->dev_addr, ref->size,
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dir2name[entry->direction],
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dir2name[ref->direction]);
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}
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hash_bucket_del(entry);
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dma_entry_free(entry);
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out:
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put_hash_bucket(bucket, &flags);
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}
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static void check_for_stack(struct device *dev, void *addr)
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{
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if (object_is_on_stack(addr))
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err_printk(dev, "DMA-API: device driver maps memory from stack"
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" [addr=%p]\n", addr);
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}
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static void check_sync(struct device *dev, dma_addr_t addr,
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u64 size, u64 offset, int direction, bool to_cpu)
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{
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struct dma_debug_entry ref = {
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.dev = dev,
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.dev_addr = addr,
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.size = size,
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.direction = direction,
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};
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struct dma_debug_entry *entry;
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struct hash_bucket *bucket;
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unsigned long flags;
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bucket = get_hash_bucket(&ref, &flags);
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entry = hash_bucket_find(bucket, &ref);
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if (!entry) {
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err_printk(dev, "DMA-API: device driver tries "
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"to sync DMA memory it has not allocated "
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"[device address=0x%016llx] [size=%llu bytes]\n",
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addr, size);
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goto out;
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}
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if ((offset + size) > entry->size) {
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err_printk(dev, "DMA-API: device driver syncs"
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" DMA memory outside allocated range "
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"[device address=0x%016llx] "
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"[allocation size=%llu bytes] [sync offset=%llu] "
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"[sync size=%llu]\n", entry->dev_addr, entry->size,
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offset, size);
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}
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if (direction != entry->direction) {
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err_printk(dev, "DMA-API: device driver syncs "
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"DMA memory with different direction "
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"[device address=0x%016llx] [size=%llu bytes] "
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"[mapped with %s] [synced with %s]\n",
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addr, entry->size,
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dir2name[entry->direction],
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dir2name[direction]);
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}
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if (entry->direction == DMA_BIDIRECTIONAL)
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goto out;
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if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
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!(direction == DMA_TO_DEVICE))
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err_printk(dev, "DMA-API: device driver syncs "
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"device read-only DMA memory for cpu "
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"[device address=0x%016llx] [size=%llu bytes] "
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"[mapped with %s] [synced with %s]\n",
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addr, entry->size,
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dir2name[entry->direction],
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dir2name[direction]);
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if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
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!(direction == DMA_FROM_DEVICE))
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err_printk(dev, "DMA-API: device driver syncs "
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"device write-only DMA memory to device "
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"[device address=0x%016llx] [size=%llu bytes] "
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"[mapped with %s] [synced with %s]\n",
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addr, entry->size,
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dir2name[entry->direction],
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dir2name[direction]);
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out:
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put_hash_bucket(bucket, &flags);
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}
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