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blktrace: print human-readable act_mask

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Impact: new feature, allow symbolic values in /debug/tracing/act_mask

Print stringified act_mask instead of hex value:

 # cat act_mask
 read,write,barrier,sync,queue,requeue,issue,complete,fs,pc,ahead,meta,
 discard,drv_data
 # echo "meta,write" > act_mask
 # cat act_mask
 write,meta

Also:
 - make act_mask accept "ahead", "meta", "discard" and "drv_data"
 - use strsep() instead of strchr() to parse user input
 - return -EINVAL if a token is not found in the mask map
 - fix a bug that 'value' is unsigned, so it can < 0
 - propagate error value of blk_trace_mask2str() to userspace, but not
   always return -ENXIO.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49C8AB42.1000802@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Li Zefan 2009-03-24 17:43:30 +08:00 committed by Ingo Molnar
parent e0dc81bec0
commit 093419971e
1 changed files with 65 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

103
kernel/trace/blktrace.c
View File

@ -1316,53 +1316,77 @@ struct attribute_group blk_trace_attr_group = {
.attrs = blk_trace_attrs,
};
static int blk_str2act_mask(const char *str)
static const struct {
int mask;
const char *str;
} mask_maps[] = {
{ BLK_TC_READ, "read" },
{ BLK_TC_WRITE, "write" },
{ BLK_TC_BARRIER, "barrier" },
{ BLK_TC_SYNC, "sync" },
{ BLK_TC_QUEUE, "queue" },
{ BLK_TC_REQUEUE, "requeue" },
{ BLK_TC_ISSUE, "issue" },
{ BLK_TC_COMPLETE, "complete" },
{ BLK_TC_FS, "fs" },
{ BLK_TC_PC, "pc" },
{ BLK_TC_AHEAD, "ahead" },
{ BLK_TC_META, "meta" },
{ BLK_TC_DISCARD, "discard" },
{ BLK_TC_DRV_DATA, "drv_data" },
};
static int blk_trace_str2mask(const char *str)
{
int i;
int mask = 0;
char *copy = kstrdup(str, GFP_KERNEL), *s;
char *s, *token;
if (copy == NULL)
s = kstrdup(str, GFP_KERNEL);
if (s == NULL)
return -ENOMEM;
s = strstrip(copy);
s = strstrip(s);
while (1) {
char *sep = strchr(s, ',');
if (sep != NULL)
*sep = '\0';
if (strcasecmp(s, "barrier") == 0)
mask |= BLK_TC_BARRIER;
else if (strcasecmp(s, "complete") == 0)
mask |= BLK_TC_COMPLETE;
else if (strcasecmp(s, "fs") == 0)
mask |= BLK_TC_FS;
else if (strcasecmp(s, "issue") == 0)
mask |= BLK_TC_ISSUE;
else if (strcasecmp(s, "pc") == 0)
mask |= BLK_TC_PC;
else if (strcasecmp(s, "queue") == 0)
mask |= BLK_TC_QUEUE;
else if (strcasecmp(s, "read") == 0)
mask |= BLK_TC_READ;
else if (strcasecmp(s, "requeue") == 0)
mask |= BLK_TC_REQUEUE;
else if (strcasecmp(s, "sync") == 0)
mask |= BLK_TC_SYNC;
else if (strcasecmp(s, "write") == 0)
mask |= BLK_TC_WRITE;
if (sep == NULL)
token = strsep(&s, ",");
if (token == NULL)
break;
s = sep + 1;
if (*token == '\0')
continue;
for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
if (strcasecmp(token, mask_maps[i].str) == 0) {
mask |= mask_maps[i].mask;
break;
}
kfree(copy);
}
if (i == ARRAY_SIZE(mask_maps)) {
mask = -EINVAL;
break;
}
}
kfree(s);
return mask;
}
static ssize_t blk_trace_mask2str(char *buf, int mask)
{
int i;
char *p = buf;
for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
if (mask & mask_maps[i].mask) {
p += sprintf(p, "%s%s",
(p == buf) ? "" : ",", mask_maps[i].str);
}
}
*p++ = '\n';
return p - buf;
}
static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
{
if (bdev->bd_disk == NULL)
@ -1399,7 +1423,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
if (q->blk_trace == NULL)
ret = sprintf(buf, "disabled\n");
else if (attr == &dev_attr_act_mask)
ret = sprintf(buf, "%#x\n", q->blk_trace->act_mask);
ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
else if (attr == &dev_attr_pid)
ret = sprintf(buf, "%u\n", q->blk_trace->pid);
else if (attr == &dev_attr_start_lba)
@ -1424,7 +1448,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
struct request_queue *q;
struct hd_struct *p;
u64 value;
ssize_t ret = -ENXIO;
ssize_t ret = -EINVAL;
if (count == 0)
goto out;
@ -1432,13 +1456,16 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
if (attr == &dev_attr_act_mask) {
if (sscanf(buf, "%llx", &value) != 1) {
/* Assume it is a list of trace category names */
value = blk_str2act_mask(buf);
if (value < 0)
ret = blk_trace_str2mask(buf);
if (ret < 0)
goto out;
value = ret;
}
} else if (sscanf(buf, "%llu", &value) != 1)
goto out;
ret = -ENXIO;
lock_kernel();
p = dev_to_part(dev);
bdev = bdget(part_devt(p));