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ref_tracker: have callers pass output function to pr_ostream()

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In a later patch, we'll be adding a 3rd mechanism for outputting
ref_tracker info via seq_file. Instead of a conditional, have the caller
set a pointer to an output function in struct ostream. As part of this,
the log prefix must be explicitly passed in, as it's too late for the
pr_fmt macro.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20250618-reftrack-dbgfs-v15-3-24fc37ead144@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jeff Layton
2025-06-18 10:24:16 -04:00
committed by Jakub Kicinski
parent e209f9193a
commit 49c94af071
2 changed files with 39 additions and 15 deletions
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2
include/linux/ref_tracker.h
View File

@@ -6,6 +6,8 @@
#include <linux/spinlock.h>
#include <linux/stackdepot.h>
#define __ostream_printf __printf(2, 3)
struct ref_tracker;
struct ref_tracker_dir {

52
lib/ref_tracker.c
View File

@@ -63,21 +63,38 @@ ref_tracker_get_stats(struct ref_tracker_dir *dir, unsigned int limit)
}
struct ostream {
void __ostream_printf (*func)(struct ostream *stream, char *fmt, ...);
char *prefix;
char *buf;
int size, used;
};
static void __ostream_printf pr_ostream_log(struct ostream *stream, char *fmt, ...)
{
va_list args;
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
}
static void __ostream_printf pr_ostream_buf(struct ostream *stream, char *fmt, ...)
{
int ret, len = stream->size - stream->used;
va_list args;
va_start(args, fmt);
ret = vsnprintf(stream->buf + stream->used, len, fmt, args);
va_end(args);
if (ret > 0)
stream->used += min(ret, len);
}
#define pr_ostream(stream, fmt, args...) \
({ \
struct ostream *_s = (stream); \
\
if (!_s->buf) { \
pr_err(fmt, ##args); \
} else { \
int ret, len = _s->size - _s->used; \
ret = snprintf(_s->buf + _s->used, len, pr_fmt(fmt), ##args); \
_s->used += min(ret, len); \
} \
_s->func(_s, fmt, ##args); \
})
static void
@@ -96,8 +113,8 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
stats = ref_tracker_get_stats(dir, display_limit);
if (IS_ERR(stats)) {
pr_ostream(s, "%s@%p: couldn't get stats, error %pe\n",
dir->name, dir, stats);
pr_ostream(s, "%s%s@%p: couldn't get stats, error %pe\n",
s->prefix, dir->name, dir, stats);
return;
}
@@ -107,14 +124,15 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
stack = stats->stacks[i].stack_handle;
if (sbuf && !stack_depot_snprint(stack, sbuf, STACK_BUF_SIZE, 4))
sbuf[0] = 0;
pr_ostream(s, "%s@%p has %d/%d users at\n%s\n", dir->name, dir,
stats->stacks[i].count, stats->total, sbuf);
pr_ostream(s, "%s%s@%p has %d/%d users at\n%s\n", s->prefix,
dir->name, dir, stats->stacks[i].count,
stats->total, sbuf);
skipped -= stats->stacks[i].count;
}
if (skipped)
pr_ostream(s, "%s@%p skipped reports about %d/%d users.\n",
dir->name, dir, skipped, stats->total);
pr_ostream(s, "%s%s@%p skipped reports about %d/%d users.\n",
s->prefix, dir->name, dir, skipped, stats->total);
kfree(sbuf);
@@ -124,7 +142,8 @@ __ref_tracker_dir_pr_ostream(struct ref_tracker_dir *dir,
void ref_tracker_dir_print_locked(struct ref_tracker_dir *dir,
unsigned int display_limit)
{
struct ostream os = {};
struct ostream os = { .func = pr_ostream_log,
.prefix = "ref_tracker: " };
__ref_tracker_dir_pr_ostream(dir, display_limit, &os);
}
@@ -143,7 +162,10 @@ EXPORT_SYMBOL(ref_tracker_dir_print);
int ref_tracker_dir_snprint(struct ref_tracker_dir *dir, char *buf, size_t size)
{
struct ostream os = { .buf = buf, .size = size };
struct ostream os = { .func = pr_ostream_buf,
.prefix = "ref_tracker: ",
.buf = buf,
.size = size };
unsigned long flags;
spin_lock_irqsave(&dir->lock, flags);