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author | Kent Overstreet <kent.overstreet@gmail.com> | 2018-01-08 21:21:25 +0100 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-01-08 21:29:00 +0100 |
commit | e4bf791937d82afca79e1df4063f72dbc6960ac7 (patch) | |
tree | 5c131edb13307bce302ba252a2624cca71176ba7 /drivers/md/bcache/closure.c | |
parent | bcache: allow quick writeback when backing idle (diff) | |
download | linux-e4bf791937d82afca79e1df4063f72dbc6960ac7.tar.xz linux-e4bf791937d82afca79e1df4063f72dbc6960ac7.zip |
bcache: Fix, improve efficiency of closure_sync()
Eliminates cases where sync can race and fail to complete / get stuck.
Removes many status flags and simplifies entering-and-exiting closure
sleeping behaviors.
[mlyle: fixed conflicts due to changed return behavior in mainline.
extended commit comment, and squashed down two commits that were mostly
contradictory to get to this state. Changed __set_current_state to
set_current_state per Jens review comment]
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Michael Lyle <mlyle@lyle.org>
Reviewed-by: Michael Lyle <mlyle@lyle.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache/closure.c')
-rw-r--r-- | drivers/md/bcache/closure.c | 46 |
1 files changed, 23 insertions, 23 deletions
diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c index 1841d0359bac..ca7ace6962a4 100644 --- a/drivers/md/bcache/closure.c +++ b/drivers/md/bcache/closure.c @@ -18,10 +18,6 @@ static inline void closure_put_after_sub(struct closure *cl, int flags) BUG_ON(flags & CLOSURE_GUARD_MASK); BUG_ON(!r && (flags & ~CLOSURE_DESTRUCTOR)); - /* Must deliver precisely one wakeup */ - if (r == 1 && (flags & CLOSURE_SLEEPING)) - wake_up_process(cl->task); - if (!r) { if (cl->fn && !(flags & CLOSURE_DESTRUCTOR)) { atomic_set(&cl->remaining, @@ -100,28 +96,34 @@ bool closure_wait(struct closure_waitlist *waitlist, struct closure *cl) } EXPORT_SYMBOL(closure_wait); -/** - * closure_sync - sleep until a closure has nothing left to wait on - * - * Sleeps until the refcount hits 1 - the thread that's running the closure owns - * the last refcount. - */ -void closure_sync(struct closure *cl) +struct closure_syncer { + struct task_struct *task; + int done; +}; + +static void closure_sync_fn(struct closure *cl) { - while (1) { - __closure_start_sleep(cl); - closure_set_ret_ip(cl); + cl->s->done = 1; + wake_up_process(cl->s->task); +} - if ((atomic_read(&cl->remaining) & - CLOSURE_REMAINING_MASK) == 1) - break; +void __closure_sync(struct closure *cl) +{ + struct closure_syncer s = { .task = current }; + cl->s = &s; + continue_at(cl, closure_sync_fn, NULL); + + while (1) { + set_current_state(TASK_UNINTERRUPTIBLE); + if (s.done) + break; schedule(); } - __closure_end_sleep(cl); + __set_current_state(TASK_RUNNING); } -EXPORT_SYMBOL(closure_sync); +EXPORT_SYMBOL(__closure_sync); #ifdef CONFIG_BCACHE_CLOSURES_DEBUG @@ -168,12 +170,10 @@ static int debug_seq_show(struct seq_file *f, void *data) cl, (void *) cl->ip, cl->fn, cl->parent, r & CLOSURE_REMAINING_MASK); - seq_printf(f, "%s%s%s%s\n", + seq_printf(f, "%s%s\n", test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&cl->work)) ? "Q" : "", - r & CLOSURE_RUNNING ? "R" : "", - r & CLOSURE_STACK ? "S" : "", - r & CLOSURE_SLEEPING ? "Sl" : ""); + r & CLOSURE_RUNNING ? "R" : ""); if (r & CLOSURE_WAITING) seq_printf(f, " W %pF\n", |