OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Merge branch 'dma-debug/2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into core/iommu

This commit is contained in:
Ingo Molnar 2009-06-07 11:36:02 +02:00
parent 56fdd18c7b bdc2911cde
commit 62a6f465f6
3 changed files with 288 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
Documentation/DMA-API.txt
View File

@ -704,12 +704,24 @@ this directory the following files can currently be found:
The current number of free dma_debug_entries
in the allocator.
dma-api/driver-filter
You can write a name of a driver into this file
to limit the debug output to requests from that
particular driver. Write an empty string to
that file to disable the filter and see
all errors again.
If you have this code compiled into your kernel it will be enabled by default.
If you want to boot without the bookkeeping anyway you can provide
'dma_debug=off' as a boot parameter. This will disable DMA-API debugging.
Notice that you can not enable it again at runtime. You have to reboot to do
so.
If you want to see debug messages only for a special device driver you can
specify the dma_debug_driver=<drivername> parameter. This will enable the
driver filter at boot time. The debug code will only print errors for that
driver afterwards. This filter can be disabled or changed later using debugfs.
When the code disables itself at runtime this is most likely because it ran
out of dma_debug_entries. These entries are preallocated at boot. The number
of preallocated entries is defined per architecture. If it is too low for you

7
Documentation/kernel-parameters.txt
View File

@ -641,6 +641,13 @@ and is between 256 and 4096 characters. It is defined in the file
DMA-API debugging code disables itself because the
architectural default is too low.
dma_debug_driver=<driver_name>
With this option the DMA-API debugging driver
filter feature can be enabled at boot time. Just
pass the driver to filter for as the parameter.
The filter can be disabled or changed to another
driver later using sysfs.
dscc4.setup= [NET]
dtc3181e= [HW,SCSI]

291
lib/dma-debug.c
View File

@ -23,9 +23,11 @@
#include <linux/dma-debug.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/uaccess.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>
@ -98,6 +100,16 @@ 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 *type2name[4] = { "single", "page",
"scather-gather", "coherent" };
@ -105,6 +117,11 @@ static const char *type2name[4] = { "single", "page",
static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
"DMA_FROM_DEVICE", "DMA_NONE" };
/* little merge helper - remove it after the merge window */
#ifndef BUS_NOTIFY_UNBOUND_DRIVER
#define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
#endif
/*
* 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
@ -128,9 +145,48 @@ static inline void dump_entry_trace(struct dma_debug_entry *entry)
#endif
}
static bool driver_filter(struct device *dev)
{
/* driver filter off */
if (likely(!current_driver_name[0]))
return true;
/* driver filter on and initialized */
if (current_driver && dev->driver == current_driver)
return true;
/* driver filter on but not yet initialized */
if (!current_driver && current_driver_name[0]) {
struct device_driver *drv = get_driver(dev->driver);
unsigned long flags;
bool ret = false;
if (!drv)
return false;
/* lock to protect against change of current_driver_name */
read_lock_irqsave(&driver_name_lock, flags);
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);
put_driver(drv);
return ret;
}
return false;
}
#define err_printk(dev, entry, format, arg...) do { \
error_count += 1; \
if (show_all_errors || show_num_errors > 0) { \
if (driver_filter(dev) && \
(show_all_errors || show_num_errors > 0)) { \
WARN(1, "%s %s: " format, \
dev_driver_string(dev), \
dev_name(dev) , ## arg); \
@ -442,6 +498,97 @@ out_err:
return -ENOMEM;
}
static ssize_t filter_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
unsigned long flags;
char buf[NAME_MAX_LEN + 1];
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)
{
unsigned long flags;
char buf[NAME_MAX_LEN];
size_t len = NAME_MAX_LEN - 1;
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, len);
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])
printk(KERN_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; ++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;
printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
current_driver_name);
out_unlock:
write_unlock_irqrestore(&driver_name_lock, flags);
return count;
}
const struct file_operations filter_fops = {
.read = filter_read,
.write = filter_write,
};
static int dma_debug_fs_init(void)
{
dma_debug_dent = debugfs_create_dir("dma-api", NULL);
@ -485,6 +632,11 @@ static int dma_debug_fs_init(void)
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:
@ -493,9 +645,60 @@ out_err:
return -ENOMEM;
}
static int device_dma_allocations(struct device *dev)
{
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;
}
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;
int count;
switch (action) {
case BUS_NOTIFY_UNBOUND_DRIVER:
count = device_dma_allocations(dev);
if (count == 0)
break;
err_printk(dev, NULL, "DMA-API: device driver has pending "
"DMA allocations while released from device "
"[count=%d]\n", count);
break;
default:
break;
}
return 0;
}
void dma_debug_add_bus(struct bus_type *bus)
{
/* FIXME: register notifier */
struct notifier_block *nb;
nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
if (nb == NULL) {
printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
return;
}
nb->notifier_call = dma_debug_device_change;
bus_register_notifier(bus, nb);
}
/*
@ -818,15 +1021,15 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
entry->type = dma_debug_sg;
entry->dev = dev;
entry->paddr = sg_phys(s);
entry->size = s->length;
entry->dev_addr = s->dma_address;
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;
if (!PageHighMem(sg_page(s))) {
check_for_stack(dev, sg_virt(s));
check_for_illegal_area(dev, sg_virt(s), s->length);
check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
}
add_dma_entry(entry);
@ -834,13 +1037,32 @@ void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL(debug_dma_map_sg);
static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
{
struct dma_debug_entry *entry;
struct hash_bucket *bucket;
unsigned long flags;
int mapped_ents = 0;
struct dma_debug_entry ref;
ref.dev = dev;
ref.dev_addr = sg_dma_address(s);
ref.size = sg_dma_len(s),
bucket = get_hash_bucket(&ref, &flags);
entry = hash_bucket_find(bucket, &ref);
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 dma_debug_entry *entry;
struct scatterlist *s;
int mapped_ents = 0, i;
unsigned long flags;
if (unlikely(global_disable))
return;
@ -851,8 +1073,8 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
.type = dma_debug_sg,
.dev = dev,
.paddr = sg_phys(s),
.dev_addr = s->dma_address,
.size = s->length,
.dev_addr = sg_dma_address(s),
.size = sg_dma_len(s),
.direction = dir,
.sg_call_ents = 0,
};
@ -860,14 +1082,9 @@ void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
if (mapped_ents && i >= mapped_ents)
break;
if (mapped_ents == 0) {
struct hash_bucket *bucket;
if (!i) {
ref.sg_call_ents = nelems;
bucket = get_hash_bucket(&ref, &flags);
entry = hash_bucket_find(bucket, &ref);
if (entry)
mapped_ents = entry->sg_mapped_ents;
put_hash_bucket(bucket, &flags);
mapped_ents = get_nr_mapped_entries(dev, s);
}
check_unmap(&ref);
@ -969,14 +1186,20 @@ void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, int direction)
{
struct scatterlist *s;
int i;
int mapped_ents = 0, i;
if (unlikely(global_disable))
return;
for_each_sg(sg, s, nelems, i) {
check_sync(dev, s->dma_address, s->dma_length, 0,
direction, true);
if (!i)
mapped_ents = get_nr_mapped_entries(dev, s);
if (i >= mapped_ents)
break;
check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
direction, true);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
@ -985,15 +1208,39 @@ void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, int direction)
{
struct scatterlist *s;
int i;
int mapped_ents = 0, i;
if (unlikely(global_disable))
return;
for_each_sg(sg, s, nelems, i) {
check_sync(dev, s->dma_address, s->dma_length, 0,
direction, false);
if (!i)
mapped_ents = get_nr_mapped_entries(dev, s);
if (i >= mapped_ents)
break;
check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
direction, 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])
printk(KERN_INFO "DMA-API: enable driver filter for "
"driver [%s]\n", current_driver_name);
return 1;
}
__setup("dma_debug_driver=", dma_debug_driver_setup);