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block/mq-deadline: Improve compile-time argument checking 

Modern compilers complain if an out-of-range value is passed to a function
argument that has an enumeration type. Let the compiler detect out-of-range
data direction arguments instead of verifying the data_dir argument at
runtime.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210618004456.7280-10-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Bart Van Assche 2021-06-17 17:44:49 -07:00 committed by Jens Axboe
parent 3e9a99eba0
commit 004a26b327
1 changed files with 49 additions and 47 deletions
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96
block/mq-deadline.c
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@ -35,6 +35,13 @@ static const int writes_starved = 2; /* max times reads can starve a write */
static const int fifo_batch = 16; /* # of sequential requests treated as one static const int fifo_batch = 16; /* # of sequential requests treated as one
by the above parameters. For throughput. */ by the above parameters. For throughput. */
enum dd_data_dir {
DD_READ = READ,
DD_WRITE = WRITE,
};
enum { DD_DIR_COUNT = 2 };
struct deadline_data { struct deadline_data {
/* /*
* run time data * run time data
@ -43,20 +50,20 @@ struct deadline_data {
/* /*
* requests (deadline_rq s) are present on both sort_list and fifo_list * requests (deadline_rq s) are present on both sort_list and fifo_list
*/ */
struct rb_root sort_list[2]; struct rb_root sort_list[DD_DIR_COUNT];
struct list_head fifo_list[2]; struct list_head fifo_list[DD_DIR_COUNT];
/* /*
* next in sort order. read, write or both are NULL * next in sort order. read, write or both are NULL
*/ */
struct request *next_rq[2]; struct request *next_rq[DD_DIR_COUNT];
unsigned int batching; /* number of sequential requests made */ unsigned int batching; /* number of sequential requests made */
unsigned int starved; /* times reads have starved writes */ unsigned int starved; /* times reads have starved writes */
/* /*
* settings that change how the i/o scheduler behaves * settings that change how the i/o scheduler behaves
*/ */
int fifo_expire[2]; int fifo_expire[DD_DIR_COUNT];
int fifo_batch; int fifo_batch;
int writes_starved; int writes_starved;
int front_merges; int front_merges;
@ -97,7 +104,7 @@ deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
static inline void static inline void
deadline_del_rq_rb(struct deadline_data *dd, struct request *rq) deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
{ {
const int data_dir = rq_data_dir(rq); const enum dd_data_dir data_dir = rq_data_dir(rq);
if (dd->next_rq[data_dir] == rq) if (dd->next_rq[data_dir] == rq)
dd->next_rq[data_dir] = deadline_latter_request(rq); dd->next_rq[data_dir] = deadline_latter_request(rq);
@ -169,10 +176,10 @@ static void dd_merged_requests(struct request_queue *q, struct request *req,
static void static void
deadline_move_request(struct deadline_data *dd, struct request *rq) deadline_move_request(struct deadline_data *dd, struct request *rq)
{ {
const int data_dir = rq_data_dir(rq); const enum dd_data_dir data_dir = rq_data_dir(rq);
dd->next_rq[READ] = NULL; dd->next_rq[DD_READ] = NULL;
dd->next_rq[WRITE] = NULL; dd->next_rq[DD_WRITE] = NULL;
dd->next_rq[data_dir] = deadline_latter_request(rq); dd->next_rq[data_dir] = deadline_latter_request(rq);
/* /*
@ -185,9 +192,10 @@ deadline_move_request(struct deadline_data *dd, struct request *rq)
* deadline_check_fifo returns 0 if there are no expired requests on the fifo, * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
* 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
*/ */
static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) static inline int deadline_check_fifo(struct deadline_data *dd,
enum dd_data_dir data_dir)
{ {
struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next); struct request *rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
/* /*
* rq is expired! * rq is expired!
@ -203,19 +211,16 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
* dispatch using arrival ordered lists. * dispatch using arrival ordered lists.
*/ */
static struct request * static struct request *
deadline_fifo_request(struct deadline_data *dd, int data_dir) deadline_fifo_request(struct deadline_data *dd, enum dd_data_dir data_dir)
{ {
struct request *rq; struct request *rq;
unsigned long flags; unsigned long flags;
if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
return NULL;
if (list_empty(&dd->fifo_list[data_dir])) if (list_empty(&dd->fifo_list[data_dir]))
return NULL; return NULL;
rq = rq_entry_fifo(dd->fifo_list[data_dir].next); rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
if (data_dir == READ || !blk_queue_is_zoned(rq->q)) if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
return rq; return rq;
/* /*
@ -223,7 +228,7 @@ deadline_fifo_request(struct deadline_data *dd, int data_dir)
* an unlocked target zone. * an unlocked target zone.
*/ */
spin_lock_irqsave(&dd->zone_lock, flags); spin_lock_irqsave(&dd->zone_lock, flags);
list_for_each_entry(rq, &dd->fifo_list[WRITE], queuelist) { list_for_each_entry(rq, &dd->fifo_list[DD_WRITE], queuelist) {
if (blk_req_can_dispatch_to_zone(rq)) if (blk_req_can_dispatch_to_zone(rq))
goto out; goto out;
} }
@ -239,19 +244,16 @@ deadline_fifo_request(struct deadline_data *dd, int data_dir)
* dispatch using sector position sorted lists. * dispatch using sector position sorted lists.
*/ */
static struct request * static struct request *
deadline_next_request(struct deadline_data *dd, int data_dir) deadline_next_request(struct deadline_data *dd, enum dd_data_dir data_dir)
{ {
struct request *rq; struct request *rq;
unsigned long flags; unsigned long flags;
if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
return NULL;
rq = dd->next_rq[data_dir]; rq = dd->next_rq[data_dir];
if (!rq) if (!rq)
return NULL; return NULL;
if (data_dir == READ || !blk_queue_is_zoned(rq->q)) if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
return rq; return rq;
/* /*
@ -276,7 +278,7 @@ deadline_next_request(struct deadline_data *dd, int data_dir)
static struct request *__dd_dispatch_request(struct deadline_data *dd) static struct request *__dd_dispatch_request(struct deadline_data *dd)
{ {
struct request *rq, *next_rq; struct request *rq, *next_rq;
int data_dir; enum dd_data_dir data_dir;
lockdep_assert_held(&dd->lock); lockdep_assert_held(&dd->lock);
@ -289,9 +291,9 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
/* /*
* batches are currently reads XOR writes * batches are currently reads XOR writes
*/ */
rq = deadline_next_request(dd, WRITE); rq = deadline_next_request(dd, DD_WRITE);
if (!rq) if (!rq)
rq = deadline_next_request(dd, READ); rq = deadline_next_request(dd, DD_READ);
if (rq && dd->batching < dd->fifo_batch) if (rq && dd->batching < dd->fifo_batch)
/* we have a next request are still entitled to batch */ /* we have a next request are still entitled to batch */
@ -302,14 +304,14 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
* data direction (read / write) * data direction (read / write)
*/ */
if (!list_empty(&dd->fifo_list[READ])) { if (!list_empty(&dd->fifo_list[DD_READ])) {
BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ])); BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[DD_READ]));
if (deadline_fifo_request(dd, WRITE) && if (deadline_fifo_request(dd, DD_WRITE) &&
(dd->starved++ >= dd->writes_starved)) (dd->starved++ >= dd->writes_starved))
goto dispatch_writes; goto dispatch_writes;
data_dir = READ; data_dir = DD_READ;
goto dispatch_find_request; goto dispatch_find_request;
} }
@ -318,13 +320,13 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd)
* there are either no reads or writes have been starved * there are either no reads or writes have been starved
*/ */
if (!list_empty(&dd->fifo_list[WRITE])) { if (!list_empty(&dd->fifo_list[DD_WRITE])) {
dispatch_writes: dispatch_writes:
BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE])); BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[DD_WRITE]));
dd->starved = 0; dd->starved = 0;
data_dir = WRITE; data_dir = DD_WRITE;
goto dispatch_find_request; goto dispatch_find_request;
} }
@ -399,8 +401,8 @@ static void dd_exit_sched(struct elevator_queue *e)
{ {
struct deadline_data *dd = e->elevator_data; struct deadline_data *dd = e->elevator_data;
BUG_ON(!list_empty(&dd->fifo_list[READ])); BUG_ON(!list_empty(&dd->fifo_list[DD_READ]));
BUG_ON(!list_empty(&dd->fifo_list[WRITE])); BUG_ON(!list_empty(&dd->fifo_list[DD_WRITE]));
kfree(dd); kfree(dd);
} }
@ -424,12 +426,12 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
} }
eq->elevator_data = dd; eq->elevator_data = dd;
INIT_LIST_HEAD(&dd->fifo_list[READ]); INIT_LIST_HEAD(&dd->fifo_list[DD_READ]);
INIT_LIST_HEAD(&dd->fifo_list[WRITE]); INIT_LIST_HEAD(&dd->fifo_list[DD_WRITE]);
dd->sort_list[READ] = RB_ROOT; dd->sort_list[DD_READ] = RB_ROOT;
dd->sort_list[WRITE] = RB_ROOT; dd->sort_list[DD_WRITE] = RB_ROOT;
dd->fifo_expire[READ] = read_expire; dd->fifo_expire[DD_READ] = read_expire;
dd->fifo_expire[WRITE] = write_expire; dd->fifo_expire[DD_WRITE] = write_expire;
dd->writes_starved = writes_starved; dd->writes_starved = writes_starved;
dd->front_merges = 1; dd->front_merges = 1;
dd->fifo_batch = fifo_batch; dd->fifo_batch = fifo_batch;
@ -497,7 +499,7 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
{ {
struct request_queue *q = hctx->queue; struct request_queue *q = hctx->queue;
struct deadline_data *dd = q->elevator->elevator_data; struct deadline_data *dd = q->elevator->elevator_data;
const int data_dir = rq_data_dir(rq); const enum dd_data_dir data_dir = rq_data_dir(rq);
lockdep_assert_held(&dd->lock); lockdep_assert_held(&dd->lock);
@ -585,7 +587,7 @@ static void dd_finish_request(struct request *rq)
spin_lock_irqsave(&dd->zone_lock, flags); spin_lock_irqsave(&dd->zone_lock, flags);
blk_req_zone_write_unlock(rq); blk_req_zone_write_unlock(rq);
if (!list_empty(&dd->fifo_list[WRITE])) if (!list_empty(&dd->fifo_list[DD_WRITE]))
blk_mq_sched_mark_restart_hctx(rq->mq_hctx); blk_mq_sched_mark_restart_hctx(rq->mq_hctx);
spin_unlock_irqrestore(&dd->zone_lock, flags); spin_unlock_irqrestore(&dd->zone_lock, flags);
} }
@ -626,8 +628,8 @@ static ssize_t __FUNC(struct elevator_queue *e, char *page) \
__data = jiffies_to_msecs(__data); \ __data = jiffies_to_msecs(__data); \
return deadline_var_show(__data, (page)); \ return deadline_var_show(__data, (page)); \
} }
SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1); SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[DD_READ], 1);
SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1); SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[DD_WRITE], 1);
SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0); SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0);
SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0); SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0);
SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0); SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0);
@ -649,8 +651,8 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)
*(__PTR) = __data; \ *(__PTR) = __data; \
return count; \ return count; \
} }
STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1); STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[DD_READ], 0, INT_MAX, 1);
STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1); STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[DD_WRITE], 0, INT_MAX, 1);
STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0); STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0); STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0);
STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0); STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0);
@ -717,8 +719,8 @@ static int deadline_##name##_next_rq_show(void *data, \
__blk_mq_debugfs_rq_show(m, rq); \ __blk_mq_debugfs_rq_show(m, rq); \
return 0; \ return 0; \
} }
DEADLINE_DEBUGFS_DDIR_ATTRS(READ, read) DEADLINE_DEBUGFS_DDIR_ATTRS(DD_READ, read)
DEADLINE_DEBUGFS_DDIR_ATTRS(WRITE, write) DEADLINE_DEBUGFS_DDIR_ATTRS(DD_WRITE, write)
#undef DEADLINE_DEBUGFS_DDIR_ATTRS #undef DEADLINE_DEBUGFS_DDIR_ATTRS
static int deadline_batching_show(void *data, struct seq_file *m) static int deadline_batching_show(void *data, struct seq_file *m)