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authorJulian Wiedmann <jwi@linux.ibm.com>2020-09-30 11:09:07 +0300
committerVasily Gorbik <gor@linux.ibm.com>2021-02-09 17:57:04 +0300
commit954d6235be412e3de33a43e68ab39342f5eccf9b (patch)
treee71aa0417acd4cc40049248eea68e860cb83fb19 /drivers/s390/cio/qdio_thinint.c
parent6bb7a51b605a36e5371a38bfa20173690251b484 (diff)
downloadlinux-954d6235be412e3de33a43e68ab39342f5eccf9b.tar.xz
s390/qdio: make thinint registration symmetric
tiqdio_add_device() adds the device to the tiq_list of eligible targets for a data IRQ, which gets walked on each QDIO Adapter Interrupt to inspect their DSCIs. But currently the tiqdio_add_device() / tiqdio_remove_device() calls are not symmetric - the device is removed within qdio_shutdown(), but only added by qdio_activate(). So depending on the call sequence and encountered errors, we might be trying to remove a list entry in qdio_shutdown() that was never even added to the list. This required additional INIT_LIST_HEAD() calls to ensure that the list entry was always in a consistent state. All drivers now fence the IRQ delivery via qdio_start_irq() / qdio_stop_irq(), so we can nicely integrate this tiq_list management with the other steps needed for QDIO Adapter IRQ (de-)registration (qdio_establish_thinint() / qdio_shutdown_thinint()). As the naming suggests these get called during qdio_establish() and qdio_shutdown(), with proper symmetry and roll-back after errors. With this we longer need to worry about misplaced list removals, and thus can clean up the list API abuse (INIT_LIST_HEAD() should not be called on list entries). Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'drivers/s390/cio/qdio_thinint.c')
-rw-r--r--drivers/s390/cio/qdio_thinint.c30
1 files changed, 12 insertions, 18 deletions
diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c
index d495bf0200aa..e1b923633372 100644
--- a/drivers/s390/cio/qdio_thinint.c
+++ b/drivers/s390/cio/qdio_thinint.c
@@ -66,22 +66,6 @@ static void put_indicator(u32 *addr)
atomic_dec(&ind->count);
}
-void tiqdio_add_device(struct qdio_irq *irq_ptr)
-{
- mutex_lock(&tiq_list_lock);
- list_add_rcu(&irq_ptr->entry, &tiq_list);
- mutex_unlock(&tiq_list_lock);
-}
-
-void tiqdio_remove_device(struct qdio_irq *irq_ptr)
-{
- mutex_lock(&tiq_list_lock);
- list_del_rcu(&irq_ptr->entry);
- mutex_unlock(&tiq_list_lock);
- synchronize_rcu();
- INIT_LIST_HEAD(&irq_ptr->entry);
-}
-
static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
{
return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
@@ -186,10 +170,15 @@ int qdio_establish_thinint(struct qdio_irq *irq_ptr)
DBF_HEX(&irq_ptr->dsci, sizeof(void *));
rc = set_subchannel_ind(irq_ptr, 0);
- if (rc)
+ if (rc) {
put_indicator(irq_ptr->dsci);
+ return rc;
+ }
- return rc;
+ mutex_lock(&tiq_list_lock);
+ list_add_rcu(&irq_ptr->entry, &tiq_list);
+ mutex_unlock(&tiq_list_lock);
+ return 0;
}
void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
@@ -197,6 +186,11 @@ void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
if (!is_thinint_irq(irq_ptr))
return;
+ mutex_lock(&tiq_list_lock);
+ list_del_rcu(&irq_ptr->entry);
+ mutex_unlock(&tiq_list_lock);
+ synchronize_rcu();
+
/* reset adapter interrupt indicators */
set_subchannel_ind(irq_ptr, 1);
put_indicator(irq_ptr->dsci);