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linux-next/drivers/infiniband/hw/qib/qib_debugfs.c
Mike Marciniszyn c62fb260a8 IB/hfi1,IB/qib: Fix qp_stats sleep with rcu read lock held
The qp init function does a kzalloc() while holding the RCU
lock that encounters the following warning with a debug kernel
when a cat of the qp_stats is done:

[  231.723948] rcu_scheduler_active = 1, debug_locks = 0
[  231.731939] 3 locks held by cat/11355:
[  231.736492]  #0:  (debugfs_srcu){......}, at: [<ffffffff813001a5>] debugfs_use_file_start+0x5/0x90
[  231.746955]  #1:  (&p->lock){+.+.+.}, at: [<ffffffff81289a6c>] seq_read+0x4c/0x3c0
[  231.755873]  #2:  (rcu_read_lock){......}, at: [<ffffffffa0a0c535>] _qp_stats_seq_start+0x5/0xd0 [hfi1]
[  231.766862]

The init functions do an implicit next which requires the rcu read lock
before the kzalloc().

Fix for both drivers is to change the scope of the init function to only
do the allocation and the initialization of the just allocated iter.

The implict next is moved back into the respective start functions to fix
the issue.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
CC: <stable@vger.kernel.org> # 4.6.x-
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-08-22 14:31:34 -04:00

290 lines
6.5 KiB
C

#ifdef CONFIG_DEBUG_FS
/*
* Copyright (c) 2013 Intel Corporation. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include "qib.h"
#include "qib_verbs.h"
#include "qib_debugfs.h"
static struct dentry *qib_dbg_root;
#define DEBUGFS_FILE(name) \
static const struct seq_operations _##name##_seq_ops = { \
.start = _##name##_seq_start, \
.next = _##name##_seq_next, \
.stop = _##name##_seq_stop, \
.show = _##name##_seq_show \
}; \
static int _##name##_open(struct inode *inode, struct file *s) \
{ \
struct seq_file *seq; \
int ret; \
ret = seq_open(s, &_##name##_seq_ops); \
if (ret) \
return ret; \
seq = s->private_data; \
seq->private = inode->i_private; \
return 0; \
} \
static const struct file_operations _##name##_file_ops = { \
.owner = THIS_MODULE, \
.open = _##name##_open, \
.read = seq_read, \
.llseek = seq_lseek, \
.release = seq_release \
};
#define DEBUGFS_FILE_CREATE(name) \
do { \
struct dentry *ent; \
ent = debugfs_create_file(#name , 0400, ibd->qib_ibdev_dbg, \
ibd, &_##name##_file_ops); \
if (!ent) \
pr_warn("create of " #name " failed\n"); \
} while (0)
static void *_opcode_stats_seq_start(struct seq_file *s, loff_t *pos)
{
struct qib_opcode_stats_perctx *opstats;
if (*pos >= ARRAY_SIZE(opstats->stats))
return NULL;
return pos;
}
static void *_opcode_stats_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct qib_opcode_stats_perctx *opstats;
++*pos;
if (*pos >= ARRAY_SIZE(opstats->stats))
return NULL;
return pos;
}
static void _opcode_stats_seq_stop(struct seq_file *s, void *v)
{
/* nothing allocated */
}
static int _opcode_stats_seq_show(struct seq_file *s, void *v)
{
loff_t *spos = v;
loff_t i = *spos, j;
u64 n_packets = 0, n_bytes = 0;
struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
struct qib_devdata *dd = dd_from_dev(ibd);
for (j = 0; j < dd->first_user_ctxt; j++) {
if (!dd->rcd[j])
continue;
n_packets += dd->rcd[j]->opstats->stats[i].n_packets;
n_bytes += dd->rcd[j]->opstats->stats[i].n_bytes;
}
if (!n_packets && !n_bytes)
return SEQ_SKIP;
seq_printf(s, "%02llx %llu/%llu\n", i,
(unsigned long long) n_packets,
(unsigned long long) n_bytes);
return 0;
}
DEBUGFS_FILE(opcode_stats)
static void *_ctx_stats_seq_start(struct seq_file *s, loff_t *pos)
{
struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
struct qib_devdata *dd = dd_from_dev(ibd);
if (!*pos)
return SEQ_START_TOKEN;
if (*pos >= dd->first_user_ctxt)
return NULL;
return pos;
}
static void *_ctx_stats_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
struct qib_devdata *dd = dd_from_dev(ibd);
if (v == SEQ_START_TOKEN)
return pos;
++*pos;
if (*pos >= dd->first_user_ctxt)
return NULL;
return pos;
}
static void _ctx_stats_seq_stop(struct seq_file *s, void *v)
{
/* nothing allocated */
}
static int _ctx_stats_seq_show(struct seq_file *s, void *v)
{
loff_t *spos;
loff_t i, j;
u64 n_packets = 0;
struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
struct qib_devdata *dd = dd_from_dev(ibd);
if (v == SEQ_START_TOKEN) {
seq_puts(s, "Ctx:npkts\n");
return 0;
}
spos = v;
i = *spos;
if (!dd->rcd[i])
return SEQ_SKIP;
for (j = 0; j < ARRAY_SIZE(dd->rcd[i]->opstats->stats); j++)
n_packets += dd->rcd[i]->opstats->stats[j].n_packets;
if (!n_packets)
return SEQ_SKIP;
seq_printf(s, " %llu:%llu\n", i, n_packets);
return 0;
}
DEBUGFS_FILE(ctx_stats)
static void *_qp_stats_seq_start(struct seq_file *s, loff_t *pos)
__acquires(RCU)
{
struct qib_qp_iter *iter;
loff_t n = *pos;
iter = qib_qp_iter_init(s->private);
/* stop calls rcu_read_unlock */
rcu_read_lock();
if (!iter)
return NULL;
do {
if (qib_qp_iter_next(iter)) {
kfree(iter);
return NULL;
}
} while (n--);
return iter;
}
static void *_qp_stats_seq_next(struct seq_file *s, void *iter_ptr,
loff_t *pos)
__must_hold(RCU)
{
struct qib_qp_iter *iter = iter_ptr;
(*pos)++;
if (qib_qp_iter_next(iter)) {
kfree(iter);
return NULL;
}
return iter;
}
static void _qp_stats_seq_stop(struct seq_file *s, void *iter_ptr)
__releases(RCU)
{
rcu_read_unlock();
}
static int _qp_stats_seq_show(struct seq_file *s, void *iter_ptr)
{
struct qib_qp_iter *iter = iter_ptr;
if (!iter)
return 0;
qib_qp_iter_print(s, iter);
return 0;
}
DEBUGFS_FILE(qp_stats)
void qib_dbg_ibdev_init(struct qib_ibdev *ibd)
{
char name[10];
snprintf(name, sizeof(name), "qib%d", dd_from_dev(ibd)->unit);
ibd->qib_ibdev_dbg = debugfs_create_dir(name, qib_dbg_root);
if (!ibd->qib_ibdev_dbg) {
pr_warn("create of %s failed\n", name);
return;
}
DEBUGFS_FILE_CREATE(opcode_stats);
DEBUGFS_FILE_CREATE(ctx_stats);
DEBUGFS_FILE_CREATE(qp_stats);
}
void qib_dbg_ibdev_exit(struct qib_ibdev *ibd)
{
if (!qib_dbg_root)
goto out;
debugfs_remove_recursive(ibd->qib_ibdev_dbg);
out:
ibd->qib_ibdev_dbg = NULL;
}
void qib_dbg_init(void)
{
qib_dbg_root = debugfs_create_dir(QIB_DRV_NAME, NULL);
if (!qib_dbg_root)
pr_warn("init of debugfs failed\n");
}
void qib_dbg_exit(void)
{
debugfs_remove_recursive(qib_dbg_root);
qib_dbg_root = NULL;
}
#endif