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authorLinus Torvalds <torvalds@linux-foundation.org>2023-07-22 11:05:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-07-22 11:05:15 -0700
commitf036d67c02b6f6966b0d45e9a16c9f2e7ede80a3 (patch)
tree5b8183940408ed9b79203a9055f1389422ce1050
parentbdd1d82e7d02bd2764a68a5cc54533dfc2ba452a (diff)
parentbb5faa99f0ce40756ab7bbbce4f16c01ca5ebd5a (diff)
Merge tag 'block-6.5-2023-07-21' of git://git.kernel.dk/linux
Pull block fixes from Jens Axboe: - Fix for loop regressions (Mauricio) - Fix a potential stall with batched wakeups in sbitmap (David) - Fix for stall with recursive plug flushes (Ross) - Skip accounting of empty requests for blk-iocost (Chengming) - Remove a dead field in struct blk_mq_hw_ctx (Chengming) * tag 'block-6.5-2023-07-21' of git://git.kernel.dk/linux: loop: do not enforce max_loop hard limit by (new) default loop: deprecate autoloading callback loop_probe() sbitmap: fix batching wakeup blk-iocost: skip empty flush bio in iocost blk-mq: delete dead struct blk_mq_hw_ctx->queued field blk-mq: Fix stall due to recursive flush plug
-rw-r--r--block/blk-core.c3
-rw-r--r--block/blk-iocost.c4
-rw-r--r--block/blk-mq.c9
-rw-r--r--drivers/block/loop.c40
-rw-r--r--include/linux/blk-mq.h2
-rw-r--r--lib/sbitmap.c15
6 files changed, 58 insertions, 15 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 99d8b9812b18..90de50082146 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1144,8 +1144,7 @@ void __blk_flush_plug(struct blk_plug *plug, bool from_schedule)
{
if (!list_empty(&plug->cb_list))
flush_plug_callbacks(plug, from_schedule);
- if (!rq_list_empty(plug->mq_list))
- blk_mq_flush_plug_list(plug, from_schedule);
+ blk_mq_flush_plug_list(plug, from_schedule);
/*
* Unconditionally flush out cached requests, even if the unplug
* event came from schedule. Since we know hold references to the
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 9dfcf540f400..dd64e2066f01 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -2516,6 +2516,10 @@ static void calc_vtime_cost_builtin(struct bio *bio, struct ioc_gq *iocg,
u64 seek_pages = 0;
u64 cost = 0;
+ /* Can't calculate cost for empty bio */
+ if (!bio->bi_iter.bi_size)
+ goto out;
+
switch (bio_op(bio)) {
case REQ_OP_READ:
coef_seqio = ioc->params.lcoefs[LCOEF_RSEQIO];
diff --git a/block/blk-mq.c b/block/blk-mq.c
index d50b1d62a3d9..b04ff6f56926 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2754,7 +2754,14 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
{
struct request *rq;
- if (rq_list_empty(plug->mq_list))
+ /*
+ * We may have been called recursively midway through handling
+ * plug->mq_list via a schedule() in the driver's queue_rq() callback.
+ * To avoid mq_list changing under our feet, clear rq_count early and
+ * bail out specifically if rq_count is 0 rather than checking
+ * whether the mq_list is empty.
+ */
+ if (plug->rq_count == 0)
return;
plug->rq_count = 0;
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 37511d2b2caf..637c5bda2387 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1775,14 +1775,43 @@ static const struct block_device_operations lo_fops = {
/*
* If max_loop is specified, create that many devices upfront.
* This also becomes a hard limit. If max_loop is not specified,
+ * the default isn't a hard limit (as before commit 85c50197716c
+ * changed the default value from 0 for max_loop=0 reasons), just
* create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module
* init time. Loop devices can be requested on-demand with the
* /dev/loop-control interface, or be instantiated by accessing
* a 'dead' device node.
*/
static int max_loop = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
-module_param(max_loop, int, 0444);
+
+#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
+static bool max_loop_specified;
+
+static int max_loop_param_set_int(const char *val,
+ const struct kernel_param *kp)
+{
+ int ret;
+
+ ret = param_set_int(val, kp);
+ if (ret < 0)
+ return ret;
+
+ max_loop_specified = true;
+ return 0;
+}
+
+static const struct kernel_param_ops max_loop_param_ops = {
+ .set = max_loop_param_set_int,
+ .get = param_get_int,
+};
+
+module_param_cb(max_loop, &max_loop_param_ops, &max_loop, 0444);
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
+#else
+module_param(max_loop, int, 0444);
+MODULE_PARM_DESC(max_loop, "Initial number of loop devices");
+#endif
+
module_param(max_part, int, 0444);
MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
@@ -2093,14 +2122,18 @@ static void loop_remove(struct loop_device *lo)
put_disk(lo->lo_disk);
}
+#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
static void loop_probe(dev_t dev)
{
int idx = MINOR(dev) >> part_shift;
- if (max_loop && idx >= max_loop)
+ if (max_loop_specified && max_loop && idx >= max_loop)
return;
loop_add(idx);
}
+#else
+#define loop_probe NULL
+#endif /* !CONFIG_BLOCK_LEGACY_AUTOLOAD */
static int loop_control_remove(int idx)
{
@@ -2281,6 +2314,9 @@ module_exit(loop_exit);
static int __init max_loop_setup(char *str)
{
max_loop = simple_strtol(str, NULL, 0);
+#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
+ max_loop_specified = true;
+#endif
return 1;
}
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index b96e00499f9e..495ca198775f 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -397,8 +397,6 @@ struct blk_mq_hw_ctx {
*/
struct blk_mq_tags *sched_tags;
- /** @queued: Number of queued requests. */
- unsigned long queued;
/** @run: Number of dispatched requests. */
unsigned long run;
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index eff4e42c425a..d0a5081dfd12 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -550,7 +550,7 @@ EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
{
- int i, wake_index;
+ int i, wake_index, woken;
if (!atomic_read(&sbq->ws_active))
return;
@@ -567,13 +567,12 @@ static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
*/
wake_index = sbq_index_inc(wake_index);
- /*
- * It is sufficient to wake up at least one waiter to
- * guarantee forward progress.
- */
- if (waitqueue_active(&ws->wait) &&
- wake_up_nr(&ws->wait, nr))
- break;
+ if (waitqueue_active(&ws->wait)) {
+ woken = wake_up_nr(&ws->wait, nr);
+ if (woken == nr)
+ break;
+ nr -= woken;
+ }
}
if (wake_index != atomic_read(&sbq->wake_index))