[PATCH V3 5/6] blk-mq: prepare for implementing hctx table via xarray

Ming Lei
2022-03-07T06:46:15Z

It is inevitable to cause use-after-free on q->queue_hw_ctx between
queue_for_each_hw_ctx() and blk_mq_update_nr_hw_queues(). And converting
to xarray can fix the uaf, meantime code gets cleaner.

Prepare for converting q->queue_hctx_ctx into xarray, one thing is that
xa_for_each() can only accept 'unsigned long' as index, so changes type
of hctx index of queue_for_each_hw_ctx() into 'unsigned long'.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-mq-debugfs.c | 6 +++---
block/blk-mq-sched.c | 9 +++++----
block/blk-mq-sysfs.c | 16 ++++++++++------
block/blk-mq-tag.c | 2 +-
block/blk-mq.c | 30 ++++++++++++++++--------------
drivers/block/rnbd/rnbd-clt.c | 2 +-
6 files changed, 36 insertions(+), 29 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 3a790eb4995c..e2880f6deb34 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -707,7 +707,7 @@ static void debugfs_create_files(struct dentry *parent, void *data,
void blk_mq_debugfs_register(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);

@@ -780,7 +780,7 @@ void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
void blk_mq_debugfs_register_hctxs(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
blk_mq_debugfs_register_hctx(q, hctx);
@@ -789,7 +789,7 @@ void blk_mq_debugfs_register_hctxs(struct request_queue *q)
void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
blk_mq_debugfs_unregister_hctx(hctx);
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 55488ba97823..e6ad8f761474 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -515,7 +515,7 @@ static void blk_mq_exit_sched_shared_tags(struct request_queue *queue)
static void blk_mq_sched_tags_teardown(struct request_queue *q, unsigned int flags)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i) {
if (hctx->sched_tags) {
@@ -550,9 +550,10 @@ static int blk_mq_init_sched_shared_tags(struct request_queue *queue)

int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
{
- unsigned int i, flags = q->tag_set->flags;
+ unsigned int flags = q->tag_set->flags;
struct blk_mq_hw_ctx *hctx;
struct elevator_queue *eq;
+ unsigned long i;
int ret;

if (!e) {
@@ -618,7 +619,7 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
void blk_mq_sched_free_rqs(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

if (blk_mq_is_shared_tags(q->tag_set->flags)) {
blk_mq_free_rqs(q->tag_set, q->sched_shared_tags,
@@ -635,7 +636,7 @@ void blk_mq_sched_free_rqs(struct request_queue *q)
void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
{
struct blk_mq_hw_ctx *hctx;
- unsigned int i;
+ unsigned long i;
unsigned int flags = 0;

queue_for_each_hw_ctx(q, hctx, i) {
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 674786574075..c08426975856 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -206,7 +206,7 @@ static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

lockdep_assert_held(&q->sysfs_dir_lock);

@@ -255,7 +255,8 @@ void blk_mq_sysfs_init(struct request_queue *q)
int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int ret, i;
+ unsigned long i, j;
+ int ret;

WARN_ON_ONCE(!q->kobj.parent);
lockdep_assert_held(&q->sysfs_dir_lock);
@@ -278,8 +279,10 @@ int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
return ret;

unreg:
- while (--i >= 0)
- blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
+ queue_for_each_hw_ctx(q, hctx, j) {
+ if (j < i)
+ blk_mq_unregister_hctx(hctx);
+ }

kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
kobject_del(q->mq_kobj);
@@ -290,7 +293,7 @@ int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
void blk_mq_sysfs_unregister(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

mutex_lock(&q->sysfs_dir_lock);
if (!q->mq_sysfs_init_done)
@@ -306,7 +309,8 @@ void blk_mq_sysfs_unregister(struct request_queue *q)
int blk_mq_sysfs_register(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i, ret = 0;
+ unsigned long i;
+ int ret = 0;

mutex_lock(&q->sysfs_dir_lock);
if (!q->mq_sysfs_init_done)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 0fd409b8e86e..1850a4225e12 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -515,7 +515,7 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_tag_iter_fn *fn,
bt_for_each(NULL, q, btags, fn, priv, false);
} else {
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i) {
struct blk_mq_tags *tags = hctx->tags;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 57ae9df0f4dc..bffdd71c670d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -312,7 +312,7 @@ EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
void blk_mq_wake_waiters(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- unsigned int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
if (blk_mq_hw_queue_mapped(hctx))
@@ -1442,7 +1442,7 @@ static void blk_mq_timeout_work(struct work_struct *work)
container_of(work, struct request_queue, timeout_work);
unsigned long next = 0;
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

/* A deadlock might occur if a request is stuck requiring a
* timeout at the same time a queue freeze is waiting
@@ -2143,7 +2143,7 @@ static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
void blk_mq_run_hw_queues(struct request_queue *q, bool async)
{
struct blk_mq_hw_ctx *hctx, *sq_hctx;
- int i;
+ unsigned long i;

sq_hctx = NULL;
if (blk_mq_has_sqsched(q))
@@ -2171,7 +2171,7 @@ EXPORT_SYMBOL(blk_mq_run_hw_queues);
void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
{
struct blk_mq_hw_ctx *hctx, *sq_hctx;
- int i;
+ unsigned long i;

sq_hctx = NULL;
if (blk_mq_has_sqsched(q))
@@ -2209,7 +2209,7 @@ EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
bool blk_mq_queue_stopped(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
if (blk_mq_hctx_stopped(hctx))
@@ -2248,7 +2248,7 @@ EXPORT_SYMBOL(blk_mq_stop_hw_queue);
void blk_mq_stop_hw_queues(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
blk_mq_stop_hw_queue(hctx);
@@ -2266,7 +2266,7 @@ EXPORT_SYMBOL(blk_mq_start_hw_queue);
void blk_mq_start_hw_queues(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
blk_mq_start_hw_queue(hctx);
@@ -2286,7 +2286,7 @@ EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
blk_mq_start_stopped_hw_queue(hctx, async);
@@ -3446,7 +3446,7 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
struct blk_mq_tag_set *set, int nr_queue)
{
struct blk_mq_hw_ctx *hctx;
- unsigned int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i) {
if (i == nr_queue)
@@ -3637,7 +3637,8 @@ static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,

static void blk_mq_map_swqueue(struct request_queue *q)
{
- unsigned int i, j, hctx_idx;
+ unsigned int j, hctx_idx;
+ unsigned long i;
struct blk_mq_hw_ctx *hctx;
struct blk_mq_ctx *ctx;
struct blk_mq_tag_set *set = q->tag_set;
@@ -3744,7 +3745,7 @@ static void blk_mq_map_swqueue(struct request_queue *q)
static void queue_set_hctx_shared(struct request_queue *q, bool shared)
{
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i) {
if (shared) {
@@ -3844,7 +3845,7 @@ static int blk_mq_alloc_ctxs(struct request_queue *q)
void blk_mq_release(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx, *next;
- int i;
+ unsigned long i;

queue_for_each_hw_ctx(q, hctx, i)
WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
@@ -4362,7 +4363,8 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
{
struct blk_mq_tag_set *set = q->tag_set;
struct blk_mq_hw_ctx *hctx;
- int i, ret;
+ int ret;
+ unsigned long i;

if (!set)
return -EINVAL;
@@ -4738,7 +4740,7 @@ void blk_mq_cancel_work_sync(struct request_queue *q)
{
if (queue_is_mq(q)) {
struct blk_mq_hw_ctx *hctx;
- int i;
+ unsigned long i;

cancel_delayed_work_sync(&q->requeue_work);

diff --git a/drivers/block/rnbd/rnbd-clt.c b/drivers/block/rnbd/rnbd-clt.c
index c08971de369f..58304f978e10 100644
--- a/drivers/block/rnbd/rnbd-clt.c
+++ b/drivers/block/rnbd/rnbd-clt.c
@@ -1343,7 +1343,7 @@ static inline void rnbd_init_hw_queue(struct rnbd_clt_dev *dev,

static void rnbd_init_mq_hw_queues(struct rnbd_clt_dev *dev)
{
- int i;
+ unsigned long i;
struct blk_mq_hw_ctx *hctx;
struct rnbd_queue *q;

--
2.31.1