[PATCH v4 09/12] xen/spinlock: add missing rspin_is_locked() and rspin_barrier()

From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: "Juergen Gross" <jgross@suse.com>,
	"Jan Beulich" <jbeulich@suse.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"Julien Grall" <julien@xen.org>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Paul Durrant" <paul@xen.org>
Subject: [PATCH v4 09/12] xen/spinlock: add missing rspin_is_locked() and rspin_barrier()
Date: Tue, 12 Dec 2023 10:47:22 +0100	[thread overview]
Message-ID: <20231212094725.22184-10-jgross@suse.com> (raw)
In-Reply-To: <20231212094725.22184-1-jgross@suse.com>

Add rspin_is_locked() and rspin_barrier() in order to prepare differing
spinlock_t and rspinlock_t types.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- partially carved out from V1 patch, partially new
---
 xen/arch/x86/mm/p2m-pod.c     |  2 +-
 xen/common/domain.c           |  2 +-
 xen/common/page_alloc.c       |  2 +-
 xen/common/spinlock.c         | 17 +++++++++++++++++
 xen/drivers/char/console.c    |  4 ++--
 xen/drivers/passthrough/pci.c |  2 +-
 xen/include/xen/spinlock.h    |  2 ++
 7 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c
index 61a91f5a94..40d3b25d25 100644
--- a/xen/arch/x86/mm/p2m-pod.c
+++ b/xen/arch/x86/mm/p2m-pod.c
@@ -385,7 +385,7 @@ int p2m_pod_empty_cache(struct domain *d)
 
     /* After this barrier no new PoD activities can happen. */
     BUG_ON(!d->is_dying);
-    spin_barrier(&p2m->pod.lock.lock);
+    rspin_barrier(&p2m->pod.lock.lock);
 
     lock_page_alloc(p2m);
 
diff --git a/xen/common/domain.c b/xen/common/domain.c
index dc97755391..198cb36878 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -982,7 +982,7 @@ int domain_kill(struct domain *d)
     case DOMDYING_alive:
         domain_pause(d);
         d->is_dying = DOMDYING_dying;
-        spin_barrier(&d->domain_lock);
+        rspin_barrier(&d->domain_lock);
         argo_destroy(d);
         vnuma_destroy(d->vnuma);
         domain_set_outstanding_pages(d, 0);
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index a25c00a7d4..14010b6fa5 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -476,7 +476,7 @@ unsigned long domain_adjust_tot_pages(struct domain *d, long pages)
 {
     long dom_before, dom_after, dom_claimed, sys_before, sys_after;
 
-    ASSERT(spin_is_locked(&d->page_alloc_lock));
+    ASSERT(rspin_is_locked(&d->page_alloc_lock));
     d->tot_pages += pages;
 
     /*
diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 31d12b1006..91e325f3fe 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -458,6 +458,23 @@ void _spin_barrier(spinlock_t *lock)
     spin_barrier_common(&lock->tickets, &lock->debug, LOCK_PROFILE_PAR);
 }
 
+int rspin_is_locked(const rspinlock_t *lock)
+{
+    /*
+     * Recursive locks may be locked by another CPU, yet we return
+     * "false" here, making this function suitable only for use in
+     * ASSERT()s and alike.
+     */
+    return lock->recurse_cpu == SPINLOCK_NO_CPU
+           ? spin_is_locked_common(&lock->tickets)
+           : lock->recurse_cpu == smp_processor_id();
+}
+
+void rspin_barrier(rspinlock_t *lock)
+{
+    spin_barrier_common(&lock->tickets, &lock->debug, LOCK_PROFILE_PAR);
+}
+
 int rspin_trylock(rspinlock_t *lock)
 {
     unsigned int cpu = smp_processor_id();
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 8d05c57f69..e6502641eb 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -328,7 +328,7 @@ static void cf_check do_dec_thresh(unsigned char key, struct cpu_user_regs *regs
 
 static void conring_puts(const char *str, size_t len)
 {
-    ASSERT(spin_is_locked(&console_lock));
+    ASSERT(rspin_is_locked(&console_lock));
 
     while ( len-- )
         conring[CONRING_IDX_MASK(conringp++)] = *str++;
@@ -766,7 +766,7 @@ static void __putstr(const char *str)
 {
     size_t len = strlen(str);
 
-    ASSERT(spin_is_locked(&console_lock));
+    ASSERT(rspin_is_locked(&console_lock));
 
     console_serial_puts(str, len);
     video_puts(str, len);
diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 41444f8e2e..94f52b7acc 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -64,7 +64,7 @@ void pcidevs_unlock(void)
 
 bool pcidevs_locked(void)
 {
-    return !!spin_is_locked(&_pcidevs_lock);
+    return rspin_is_locked(&_pcidevs_lock);
 }
 
 static struct radix_tree_root pci_segments;
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index d6f4b66613..e63db4eb4c 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -239,6 +239,8 @@ void rspin_lock(rspinlock_t *lock);
 unsigned long __rspin_lock_irqsave(rspinlock_t *lock);
 void rspin_unlock(rspinlock_t *lock);
 void rspin_unlock_irqrestore(rspinlock_t *lock, unsigned long flags);
+int rspin_is_locked(const rspinlock_t *lock);
+void rspin_barrier(rspinlock_t *lock);
 
 #define spin_lock(l)                  _spin_lock(l)
 #define spin_lock_cb(l, c, d)         _spin_lock_cb(l, c, d)
-- 
2.35.3


