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authorLi Zefan <lizf@cn.fujitsu.com>2009-03-24 17:43:30 +0800
committerIngo Molnar <mingo@elte.hu>2009-03-24 13:09:00 +0100
commit093419971e03362a00f499960557c119982ea09f (patch)
treef355954c6282bc6ee3d67f7ae374408821a216ef /kernel
parente0dc81bec0927fa0c8aabc521793161909eef7a5 (diff)
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blktrace: print human-readable act_mask
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/blktrace.c103
1 files changed, 65 insertions, 38 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index f69f8bd8bef9..6fb274f5f34e 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -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;
+ }
+ }
+ if (i == ARRAY_SIZE(mask_maps)) {
+ mask = -EINVAL;
+ break;
+ }
}
- kfree(copy);
+ 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));