On Wed, 18 Mar 2020, Thomas Gleixner wrote:
From: Thomas Gleixner
completion uses a wait_queue_head_t to enqueue waiters.
wait_queue_head_t contains a spinlock_t to protect the list of waiters
which excludes it from being used in truly atomic context on a PREEMPT_RT
enabled kernel.
The spinl
On Fri, Mar 20, 2020 at 10:25:41AM +1100, Julian Calaby wrote:
> > +++ b/drivers/usb/gadget/function/f_fs.c
> > @@ -1703,7 +1703,7 @@ static void ffs_data_put(struct ffs_data
> > pr_info("%s(): freeing\n", __func__);
> > ffs_data_clear(ffs);
> > BUG_O
Hi Thomas,
On Thu, Mar 19, 2020 at 7:48 AM Thomas Gleixner wrote:
>
> From: Thomas Gleixner
>
> completion uses a wait_queue_head_t to enqueue waiters.
>
> wait_queue_head_t contains a spinlock_t to protect the list of waiters
> which excludes it from being used in truly atomic context on a PREE
On Wed, Mar 18, 2020 at 1:47 PM Thomas Gleixner wrote:
>
> There is no semantical or functional change:
Ack, with just the explanation, I'm no longer objecting to this.
Plus you fixed and cleaned up the odd usb gadget code separately
(well, most of it).
Linus
On Wed, Mar 18, 2020 at 09:43:13PM +0100, Thomas Gleixner wrote:
> From: Thomas Gleixner
>
> completion uses a wait_queue_head_t to enqueue waiters.
>
> wait_queue_head_t contains a spinlock_t to protect the list of waiters
> which excludes it from being used in truly atomic context on a PREEMPT
Joel,
Joel Fernandes writes:
> On Wed, Mar 18, 2020 at 09:43:13PM +0100, Thomas Gleixner wrote:
>> The spinlock in the wait queue head cannot be replaced by a raw_spinlock
>> because:
>>
>> - wait queues can have custom wakeup callbacks, which acquire other
>> spinlock_t locks and have pot
Hi Thomas,
On Wed, Mar 18, 2020 at 09:43:13PM +0100, Thomas Gleixner wrote:
> From: Thomas Gleixner
>
> completion uses a wait_queue_head_t to enqueue waiters.
>
> wait_queue_head_t contains a spinlock_t to protect the list of waiters
> which excludes it from being used in truly atomic context
On 2020-03-18 2:43 p.m., Thomas Gleixner wrote:
> There is no semantical or functional change:
>
> - completions use the exclusive wait mode which is what swait provides
>
> - complete() wakes one exclusive waiter
>
> - complete_all() wakes all waiters while holding the lock which prote
From: Thomas Gleixner
completion uses a wait_queue_head_t to enqueue waiters.
wait_queue_head_t contains a spinlock_t to protect the list of waiters
which excludes it from being used in truly atomic context on a PREEMPT_RT
enabled kernel.
The spinlock in the wait queue head cannot be replaced b
