closures: Add closure_wait_event_timeout()

Add a closure version of wait_event_timeout(), with the same semantics.

The closure version is useful because unlike wait_event(), it allows
blocking code

closures: Add closure_wait_event_timeout()

Add a closure version of wait_event_timeout(), with the same semantics.

The closure version is useful because unlike wait_event(), it allows
blocking code to run in the conditional expression.

Cc: Coly Li <[email protected]>
Signed-off-by: Kent Overstreet <[email protected]>

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closures: fix closure_sync + closure debugging

originally, stack closures were only used synchronously, and with the
original implementation of closure_sync() the ref never hit 0; thus,
closure_put_

closures: fix closure_sync + closure debugging

originally, stack closures were only used synchronously, and with the
original implementation of closure_sync() the ref never hit 0; thus,
closure_put_after_sub() assumes that if the ref hits 0 it's on the debug
list, in debug mode.

that's no longer true with the current implementation of closure_sync,
so we need a new magic so closure_debug_destroy() doesn't pop an assert.

Signed-off-by: Kent Overstreet <[email protected]>

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closures: closure_get_not_zero(), closure_return_sync()

Provide new primitives for solving a lifetime issue with bcachefs
btree_trans objects.

closure_sync_return(): like closure_sync(), wait synch

closures: closure_get_not_zero(), closure_return_sync()

Provide new primitives for solving a lifetime issue with bcachefs
btree_trans objects.

closure_sync_return(): like closure_sync(), wait synchronously for any
outstanding gets. like closure_return, the closure is considered
"finished" and the ref left at 0.

closure_get_not_zero(): get a ref on a closure if it's alive, i.e. the
ref is not zero.

Signed-off-by: Kent Overstreet <[email protected]>

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closures: closure_sync_timeout()

Add a new variant of closure_sync_timeout() that takes a timeout.

Note that when this returns -ETIME the closure will still be waiting on
something, i.e. it's not s

closures: closure_sync_timeout()

Add a new variant of closure_sync_timeout() that takes a timeout.

Note that when this returns -ETIME the closure will still be waiting on
something, i.e. it's not safe to return if you've got a stack allocated
closure.

Signed-off-by: Kent Overstreet <[email protected]>

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closures: CLOSURE_CALLBACK() to fix type punning

Control flow integrity is now checking that type signatures match on
indirect function calls. That breaks closures, which embed a work_struct
in a cl

closures: CLOSURE_CALLBACK() to fix type punning

Control flow integrity is now checking that type signatures match on
indirect function calls. That breaks closures, which embed a work_struct
in a closure in such a way that a closure_fn may also be used as a
workqueue fn by the underlying closure code.

So we have to change closure fns to take a work_struct as their
argument - but that results in a loss of clarity, as closure fns have
different semantics from normal workqueue functions (they run owning a
ref on the closure, which must be released with continue_at() or
closure_return()).

Thus, this patc introduces CLOSURE_CALLBACK() and closure_type() macros
as suggested by Kees, to smooth things over a bit.

Suggested-by: Kees Cook <[email protected]>
Cc: Coly Li <[email protected]>
Signed-off-by: Kent Overstreet <[email protected]>

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closures: Fix race in closure_sync()

As pointed out by Linus, closure_sync() was racy; we could skip blocking
immediately after a get() and a put(), but then that would skip any
barrier correspondin

closures: Fix race in closure_sync()

As pointed out by Linus, closure_sync() was racy; we could skip blocking
immediately after a get() and a put(), but then that would skip any
barrier corresponding to the other thread's put() barrier.

To fix this, always do the full __closure_sync() sequence whenever any
get() has happened and the closure might have been used by other
threads.

Signed-off-by: Kent Overstreet <[email protected]>

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closures: Better memory barriers

atomic_(dec|sub)_return_release() are a thing now - use them.

Also, delete the useless barrier in set_closure_fn(): it's redundant
with the memory barrier in closur

closures: Better memory barriers

atomic_(dec|sub)_return_release() are a thing now - use them.

Also, delete the useless barrier in set_closure_fn(): it's redundant
with the memory barrier in closure_put(0.

Since closure_put() would now otherwise just have a release barrier, we
also need a new barrier when the ref hits 0 -
smp_acquire__after_ctrl_dep().

Signed-off-by: Kent Overstreet <[email protected]>

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closures: closure_nr_remaining()

Factor out a new helper, which returns the number of events outstanding.

Signed-off-by: Kent Overstreet <[email protected]>

closures: closure_wait_event()

Like wait_event() - except, because it uses closures and closure
waitlists it doesn't have the restriction on modifying task state inside
the condition check, like wai

closures: closure_wait_event()

Like wait_event() - except, because it uses closures and closure
waitlists it doesn't have the restriction on modifying task state inside
the condition check, like wait_event() does.

Signed-off-by: Kent Overstreet <[email protected]>
Acked-by: Coly Li <[email protected]>

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bcache: move closures to lib/

Prep work for bcachefs - being a fork of bcache it also uses closures

Signed-off-by: Kent Overstreet <[email protected]>
Acked-by: Coly Li <[email protected]>
Rev

bcache: move closures to lib/

Prep work for bcachefs - being a fork of bcache it also uses closures

Signed-off-by: Kent Overstreet <[email protected]>
Acked-by: Coly Li <[email protected]>
Reviewed-by: Randy Dunlap <[email protected]>

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