All callers of bio_blkcg actually want the CSS, so replace it with an
interface that does return the CSS. This now allows to move
struct blkcg_gq to block/blk-cgroup.h instead of exposing it in a
public header.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-cgroup.c | 18 ++++++++-
block/blk-cgroup.h | 67 ++++++++++++++++++++++++++++--
drivers/block/loop.c | 12 +++---
include/linux/blk-cgroup.h | 83 +++-----------------------------------
kernel/trace/blktrace.c | 6 ++-
5 files changed, 97 insertions(+), 89 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index bb52797c02bd7..8e32cc494808d 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -155,6 +155,22 @@ static void blkg_async_bio_workfn(struct work_struct *work)
blk_finish_plug(&plug);
}
+/**
+ * bio_blkcg_css - return the blkcg CSS associated with a bio
+ * @bio: target bio
+ *
+ * This returns the CSS for the blkcg associated with a bio, or %NULL if not
+ * associated. Callers are expected to either handle %NULL or know association
+ * has been done prior to calling this.
+ */
+struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio)
+{
+ if (!bio || !bio->bi_blkg)
+ return NULL;
+ return &bio->bi_blkg->blkcg->css;
+}
+EXPORT_SYMBOL_GPL(bio_blkcg_css);
+
/**
* blkcg_parent - get the parent of a blkcg
* @blkcg: blkcg of interest
@@ -1938,7 +1954,7 @@ void bio_associate_blkg(struct bio *bio)
rcu_read_lock();
if (bio->bi_blkg)
- css = &bio_blkcg(bio)->css;
+ css = bio_blkcg_css(bio);
else
css = blkcg_css();
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index b00fb1169e7ce..03405ddf2a7ba 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -25,6 +25,64 @@ struct blkg_policy_data;
#define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
#ifdef CONFIG_BLK_CGROUP
+
+enum blkg_iostat_type {
+ BLKG_IOSTAT_READ,
+ BLKG_IOSTAT_WRITE,
+ BLKG_IOSTAT_DISCARD,
+
+ BLKG_IOSTAT_NR,
+};
+
+struct blkg_iostat {
+ u64 bytes[BLKG_IOSTAT_NR];
+ u64 ios[BLKG_IOSTAT_NR];
+};
+
+struct blkg_iostat_set {
+ struct u64_stats_sync sync;
+ struct blkg_iostat cur;
+ struct blkg_iostat last;
+};
+
+/* association between a blk cgroup and a request queue */
+struct blkcg_gq {
+ /* Pointer to the associated request_queue */
+ struct request_queue *q;
+ struct list_head q_node;
+ struct hlist_node blkcg_node;
+ struct blkcg *blkcg;
+
+ /* all non-root blkcg_gq's are guaranteed to have access to parent */
+ struct blkcg_gq *parent;
+
+ /* reference count */
+ struct percpu_ref refcnt;
+
+ /* is this blkg online? protected by both blkcg and q locks */
+ bool online;
+
+ struct blkg_iostat_set __percpu *iostat_cpu;
+ struct blkg_iostat_set iostat;
+
+ struct blkg_policy_data *pd[BLKCG_MAX_POLS];
+
+ spinlock_t async_bio_lock;
+ struct bio_list async_bios;
+ union {
+ struct work_struct async_bio_work;
+ struct work_struct free_work;
+ };
+
+ atomic_t use_delay;
+ atomic64_t delay_nsec;
+ atomic64_t delay_start;
+ u64 last_delay;
+ int last_use;
+
+ struct rcu_head rcu_head;
+};
+
struct blkcg {
struct cgroup_subsys_state css;
spinlock_t lock;
@@ -173,9 +231,9 @@ static inline struct cgroup_subsys_state *blkcg_css(void)
*
* In order to avoid priority inversions we sometimes need to issue a bio as if
* it were attached to the root blkg, and then backcharge to the actual owning
- * blkg. The idea is we do bio_blkcg() to look up the actual context for the
- * bio and attach the appropriate blkg to the bio. Then we call this helper and
- * if it is true run with the root blkg for that queue and then do any
+ * blkg. The idea is we do bio_blkcg_css() to look up the actual context for
+ * the bio and attach the appropriate blkg to the bio. Then we call this helper
+ * and if it is true run with the root blkg for that queue and then do any
* backcharging to the originating cgroup once the io is complete.
*/
static inline bool bio_issue_as_root_blkg(struct bio *bio)
@@ -464,6 +522,9 @@ struct blkcg_policy_data {
struct blkcg_policy {
};
+struct blkcg {
+};
+
#ifdef CONFIG_BLOCK
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 976cf987b3920..fabcf647306af 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1829,12 +1829,14 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
cmd->blkcg_css = NULL;
cmd->memcg_css = NULL;
#ifdef CONFIG_BLK_CGROUP
- if (rq->bio && rq->bio->bi_blkg) {
- cmd->blkcg_css = &bio_blkcg(rq->bio)->css;
+ if (rq->bio) {
+ cmd->blkcg_css = bio_blkcg_css(rq->bio);
#ifdef CONFIG_MEMCG
- cmd->memcg_css =
- cgroup_get_e_css(cmd->blkcg_css->cgroup,
- &memory_cgrp_subsys);
+ if (cmd->blkcg_css) {
+ cmd->memcg_css =
+ cgroup_get_e_css(cmd->blkcg_css->cgroup,
+ &memory_cgrp_subsys);
+ }
#endif
}
#endif
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index d7b1880950402..97c7968e32040 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -28,94 +28,18 @@
#define FC_APPID_LEN 129
#ifdef CONFIG_BLK_CGROUP
-
-enum blkg_iostat_type {
- BLKG_IOSTAT_READ,
- BLKG_IOSTAT_WRITE,
- BLKG_IOSTAT_DISCARD,
-
- BLKG_IOSTAT_NR,
-};
-
-struct blkg_iostat {
- u64 bytes[BLKG_IOSTAT_NR];
- u64 ios[BLKG_IOSTAT_NR];
-};
-
-struct blkg_iostat_set {
- struct u64_stats_sync sync;
- struct blkg_iostat cur;
- struct blkg_iostat last;
-};
-
-/* association between a blk cgroup and a request queue */
-struct blkcg_gq {
- /* Pointer to the associated request_queue */
- struct request_queue *q;
- struct list_head q_node;
- struct hlist_node blkcg_node;
- struct blkcg *blkcg;
-
- /* all non-root blkcg_gq's are guaranteed to have access to parent */
- struct blkcg_gq *parent;
-
- /* reference count */
- struct percpu_ref refcnt;
-
- /* is this blkg online? protected by both blkcg and q locks */
- bool online;
-
- struct blkg_iostat_set __percpu *iostat_cpu;
- struct blkg_iostat_set iostat;
-
- struct blkg_policy_data *pd[BLKCG_MAX_POLS];
-
- spinlock_t async_bio_lock;
- struct bio_list async_bios;
- union {
- struct work_struct async_bio_work;
- struct work_struct free_work;
- };
-
- atomic_t use_delay;
- atomic64_t delay_nsec;
- atomic64_t delay_start;
- u64 last_delay;
- int last_use;
-
- struct rcu_head rcu_head;
-};
-
extern struct cgroup_subsys_state * const blkcg_root_css;
void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay);
void blkcg_maybe_throttle_current(void);
-
-/**
- * bio_blkcg - grab the blkcg associated with a bio
- * @bio: target bio
- *
- * This returns the blkcg associated with a bio, %NULL if not associated.
- * Callers are expected to either handle %NULL or know association has been
- * done prior to calling this.
- */
-static inline struct blkcg *bio_blkcg(struct bio *bio)
-{
- if (bio && bio->bi_blkg)
- return bio->bi_blkg->blkcg;
- return NULL;
-}
-
bool blk_cgroup_congested(void);
void blkcg_pin_online(struct cgroup_subsys_state *blkcg_css);
void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css);
struct list_head *blkcg_get_cgwb_list(struct cgroup_subsys_state *css);
+struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio);
#else /* CONFIG_BLK_CGROUP */
-struct blkcg_gq {
-};
-
#define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL))
static inline void blkcg_maybe_throttle_current(void) { }
@@ -123,7 +47,10 @@ static inline bool blk_cgroup_congested(void) { return false; }
#ifdef CONFIG_BLOCK
static inline void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) { }
-static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
+static inline struct cgroup_subsys_state *bio_blkcg_css(struct bio *bio)
+{
+ return NULL;
+}
#endif /* CONFIG_BLOCK */
#endif /* CONFIG_BLK_CGROUP */
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 9ef349ac49c01..10a32b0f2deb6 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -783,6 +783,7 @@ void blk_trace_shutdown(struct request_queue *q)
#ifdef CONFIG_BLK_CGROUP
static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
{
+ struct cgroup_subsys_state *blkcg_css;
struct blk_trace *bt;
/* We don't use the 'bt' value here except as an optimization... */
@@ -790,9 +791,10 @@ static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
return 0;
- if (!bio->bi_blkg)
+ blkcg_css = bio_blkcg_css(bio);
+ if (!blkcg_css)
return 0;
- return cgroup_id(bio_blkcg(bio)->css.cgroup);
+ return cgroup_id(blkcg_css->cgroup);
}
#else
static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
--
2.30.2
