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tty: hvc: use mutex instead of spinlock for hvc_structs lock 

This allows hvc operations to sleep under the lock.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2018-05-01 00:55:53 +10:00 committed by Michael Ellerman
parent 021c91791a
commit a9bf5c8a27
1 changed files with 11 additions and 12 deletions
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23
drivers/tty/hvc/hvc_console.c
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@ -73,7 +73,7 @@ static LIST_HEAD(hvc_structs);
* Protect the list of hvc_struct instances from inserts and removals during
* list traversal.
*/
static DEFINE_SPINLOCK(hvc_structs_lock);
static DEFINE_MUTEX(hvc_structs_mutex);
/*
* This value is used to assign a tty->index value to a hvc_struct based
@ -83,7 +83,7 @@ static DEFINE_SPINLOCK(hvc_structs_lock);
static int last_hvc = -1;
/*
* Do not call this function with either the hvc_structs_lock or the hvc_struct
* Do not call this function with either the hvc_structs_mutex or the hvc_struct
* lock held. If successful, this function increments the kref reference
* count against the target hvc_struct so it should be released when finished.
*/
@ -92,25 +92,24 @@ static struct hvc_struct *hvc_get_by_index(int index)
struct hvc_struct *hp;
unsigned long flags;
spin_lock(&hvc_structs_lock);
mutex_lock(&hvc_structs_mutex);
list_for_each_entry(hp, &hvc_structs, next) {
spin_lock_irqsave(&hp->lock, flags);
if (hp->index == index) {
tty_port_get(&hp->port);
spin_unlock_irqrestore(&hp->lock, flags);
spin_unlock(&hvc_structs_lock);
mutex_unlock(&hvc_structs_mutex);
return hp;
}
spin_unlock_irqrestore(&hp->lock, flags);
}
hp = NULL;
mutex_unlock(&hvc_structs_mutex);
spin_unlock(&hvc_structs_lock);
return hp;
}
/*
* Initial console vtermnos for console API usage prior to full console
* initialization. Any vty adapter outside this range will not have usable
@ -224,13 +223,13 @@ static void hvc_port_destruct(struct tty_port *port)
struct hvc_struct *hp = container_of(port, struct hvc_struct, port);
unsigned long flags;
spin_lock(&hvc_structs_lock);
mutex_lock(&hvc_structs_mutex);
spin_lock_irqsave(&hp->lock, flags);
list_del(&(hp->next));
spin_unlock_irqrestore(&hp->lock, flags);
spin_unlock(&hvc_structs_lock);
mutex_unlock(&hvc_structs_mutex);
kfree(hp);
}
@ -733,11 +732,11 @@ static int khvcd(void *unused)
try_to_freeze();
wmb();
if (!cpus_are_in_xmon()) {
spin_lock(&hvc_structs_lock);
mutex_lock(&hvc_structs_mutex);
list_for_each_entry(hp, &hvc_structs, next) {
poll_mask |= hvc_poll(hp);
}
spin_unlock(&hvc_structs_lock);
mutex_unlock(&hvc_structs_mutex);
} else
poll_mask |= HVC_POLL_READ;
if (hvc_kicked)
@ -871,7 +870,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
INIT_WORK(&hp->tty_resize, hvc_set_winsz);
spin_lock_init(&hp->lock);
spin_lock(&hvc_structs_lock);
mutex_lock(&hvc_structs_mutex);
/*
* find index to use:
@ -891,7 +890,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
vtermnos[i] = vtermno;
list_add_tail(&(hp->next), &hvc_structs);
spin_unlock(&hvc_structs_lock);
mutex_unlock(&hvc_structs_mutex);
/* check if we need to re-register the kernel console */
hvc_check_console(i);