[PATCH v4 03/12] xen/spinlock: introduce new type for recursive spinlocks

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>,
	"Roger Pau Monné" <roger.pau@citrix.com>, "Wei Liu" <wl@xen.org>,
	"George Dunlap" <george.dunlap@citrix.com>,
	"Julien Grall" <julien@xen.org>,
	"Stefano Stabellini" <sstabellini@kernel.org>,
	"Paul Durrant" <paul@xen.org>
Subject: [PATCH v4 03/12] xen/spinlock: introduce new type for recursive spinlocks
Date: Tue, 12 Dec 2023 10:47:16 +0100	[thread overview]
Message-ID: <20231212094725.22184-4-jgross@suse.com> (raw)
In-Reply-To: <20231212094725.22184-1-jgross@suse.com>

Introduce a new type "rspinlock_t" to be used for recursive spinlocks.

For now it is only an alias of spinlock_t, so both types can still be
used for recursive spinlocks. This will be changed later, though.

Switch all recursive spinlocks to the new type.

Define the initializer helpers and use them where appropriate.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- carved out from V1 patch
---
 xen/arch/x86/include/asm/mm.h |  2 +-
 xen/arch/x86/mm/mm-locks.h    |  2 +-
 xen/common/domain.c           |  4 ++--
 xen/common/ioreq.c            |  2 +-
 xen/drivers/char/console.c    |  4 ++--
 xen/drivers/passthrough/pci.c |  2 +-
 xen/include/xen/sched.h       |  6 +++---
 xen/include/xen/spinlock.h    | 19 +++++++++++++++----
 8 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/xen/arch/x86/include/asm/mm.h b/xen/arch/x86/include/asm/mm.h
index 05dfe35502..8a6e0c283f 100644
--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -596,7 +596,7 @@ unsigned long domain_get_maximum_gpfn(struct domain *d);
 
 /* Definition of an mm lock: spinlock with extra fields for debugging */
 typedef struct mm_lock {
-    spinlock_t         lock;
+    rspinlock_t        lock;
     int                unlock_level;
     int                locker;          /* processor which holds the lock */
     const char        *locker_function; /* func that took it */
diff --git a/xen/arch/x86/mm/mm-locks.h b/xen/arch/x86/mm/mm-locks.h
index 00b1bc402d..b05cad1752 100644
--- a/xen/arch/x86/mm/mm-locks.h
+++ b/xen/arch/x86/mm/mm-locks.h
@@ -20,7 +20,7 @@ DECLARE_PERCPU_RWLOCK_GLOBAL(p2m_percpu_rwlock);
 
 static inline void mm_lock_init(mm_lock_t *l)
 {
-    spin_lock_init(&l->lock);
+    rspin_lock_init(&l->lock);
     l->locker = -1;
     l->locker_function = "nobody";
     l->unlock_level = 0;
diff --git a/xen/common/domain.c b/xen/common/domain.c
index c5954cdb1a..dc97755391 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -627,8 +627,8 @@ struct domain *domain_create(domid_t domid,
 
     atomic_set(&d->refcnt, 1);
     RCU_READ_LOCK_INIT(&d->rcu_lock);
-    spin_lock_init_prof(d, domain_lock);
-    spin_lock_init_prof(d, page_alloc_lock);
+    rspin_lock_init_prof(d, domain_lock);
+    rspin_lock_init_prof(d, page_alloc_lock);
     spin_lock_init(&d->hypercall_deadlock_mutex);
     INIT_PAGE_LIST_HEAD(&d->page_list);
     INIT_PAGE_LIST_HEAD(&d->extra_page_list);
diff --git a/xen/common/ioreq.c b/xen/common/ioreq.c
index 62b907f4c4..652c18a9b5 100644
--- a/xen/common/ioreq.c
+++ b/xen/common/ioreq.c
@@ -1331,7 +1331,7 @@ unsigned int ioreq_broadcast(ioreq_t *p, bool buffered)
 
 void ioreq_domain_init(struct domain *d)
 {
-    spin_lock_init(&d->ioreq_server.lock);
+    rspin_lock_init(&d->ioreq_server.lock);
 
     arch_ioreq_domain_init(d);
 }
diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c
index 0666564ec9..76e455bacd 100644
--- a/xen/drivers/char/console.c
+++ b/xen/drivers/char/console.c
@@ -120,7 +120,7 @@ static int __read_mostly sercon_handle = -1;
 int8_t __read_mostly opt_console_xen; /* console=xen */
 #endif
 
-static DEFINE_SPINLOCK(console_lock);
+static DEFINE_RSPINLOCK(console_lock);
 
 /*
  * To control the amount of printing, thresholds are added.
@@ -1178,7 +1178,7 @@ void console_force_unlock(void)
 {
     watchdog_disable();
     spin_debug_disable();
-    spin_lock_init(&console_lock);
+    rspin_lock_init(&console_lock);
     serial_force_unlock(sercon_handle);
     console_locks_busted = 1;
     console_start_sync();
diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 28ed8ea817..d604ed5634 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -50,7 +50,7 @@ struct pci_seg {
     } bus2bridge[MAX_BUSES];
 };
 
-static spinlock_t _pcidevs_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_RSPINLOCK(_pcidevs_lock);
 
 void pcidevs_lock(void)
 {
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 3609ef88c4..c6604aef78 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -376,9 +376,9 @@ struct domain
 
     rcu_read_lock_t  rcu_lock;
 
-    spinlock_t       domain_lock;
+    rspinlock_t      domain_lock;
 
-    spinlock_t       page_alloc_lock; /* protects all the following fields  */
+    rspinlock_t      page_alloc_lock; /* protects all the following fields  */
     struct page_list_head page_list;  /* linked list */
     struct page_list_head extra_page_list; /* linked list (size extra_pages) */
     struct page_list_head xenpage_list; /* linked list (size xenheap_pages) */
@@ -597,7 +597,7 @@ struct domain
 #ifdef CONFIG_IOREQ_SERVER
     /* Lock protects all other values in the sub-struct */
     struct {
-        spinlock_t              lock;
+        rspinlock_t             lock;
         struct ioreq_server     *server[MAX_NR_IOREQ_SERVERS];
     } ioreq_server;
 #endif
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index 1cd9120eac..20d15f34dd 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -45,7 +45,7 @@ union lock_debug { };
     lock profiling on:
 
     Global locks which should be subject to profiling must be declared via
-    DEFINE_SPINLOCK.
+    DEFINE_[R]SPINLOCK.
 
     For locks in structures further measures are necessary:
     - the structure definition must include a profile_head with exactly this
@@ -56,7 +56,7 @@ union lock_debug { };
     - the single locks which are subject to profiling have to be initialized
       via
 
-      spin_lock_init_prof(ptr, lock);
+      [r]spin_lock_init_prof(ptr, lock);
 
       with ptr being the main structure pointer and lock the spinlock field
 
@@ -109,12 +109,16 @@ struct lock_profile_qhead {
     spinlock_t l = _SPIN_LOCK_UNLOCKED(NULL);                                 \
     static struct lock_profile __lock_profile_data_##l = _LOCK_PROFILE(l);    \
     _LOCK_PROFILE_PTR(l)
+#define DEFINE_RSPINLOCK(l)                                                   \
+    rspinlock_t l = _SPIN_LOCK_UNLOCKED(NULL);                                \
+    static struct lock_profile __lock_profile_data_##l = _LOCK_PROFILE(l);    \
+    _LOCK_PROFILE_PTR(l)
 
-#define spin_lock_init_prof(s, l)                                             \
+#define __spin_lock_init_prof(s, l, locktype)                                 \
     do {                                                                      \
         struct lock_profile *prof;                                            \
         prof = xzalloc(struct lock_profile);                                  \
-        (s)->l = (spinlock_t)_SPIN_LOCK_UNLOCKED(prof);                       \
+        (s)->l = (locktype)_SPIN_LOCK_UNLOCKED(prof);                         \
         if ( !prof )                                                          \
         {                                                                     \
             printk(XENLOG_WARNING                                             \
@@ -128,6 +132,9 @@ struct lock_profile_qhead {
         (s)->profile_head.elem_q = prof;                                      \
     } while( 0 )
 
+#define spin_lock_init_prof(s, l) __spin_lock_init_prof(s, l, spinlock_t)
+#define rspin_lock_init_prof(s, l) __spin_lock_init_prof(s, l, rspinlock_t)
+
 void _lock_profile_register_struct(
     int32_t type, struct lock_profile_qhead *qhead, int32_t idx);
 void _lock_profile_deregister_struct(int32_t type,
@@ -151,8 +158,10 @@ struct lock_profile_qhead { };
     .debug =_LOCK_DEBUG,                                                      \
 }
 #define DEFINE_SPINLOCK(l) spinlock_t l = SPIN_LOCK_UNLOCKED
+#define DEFINE_RSPINLOCK(l) rspinlock_t l = SPIN_LOCK_UNLOCKED
 
 #define spin_lock_init_prof(s, l) spin_lock_init(&((s)->l))
+#define rspin_lock_init_prof(s, l) rspin_lock_init(&((s)->l))
 #define lock_profile_register_struct(type, ptr, idx)
 #define lock_profile_deregister_struct(type, ptr)
 #define spinlock_profile_printall(key)
@@ -182,8 +191,10 @@ typedef struct spinlock {
 #endif
 } spinlock_t;
 
+typedef spinlock_t rspinlock_t;
 
 #define spin_lock_init(l) (*(l) = (spinlock_t)SPIN_LOCK_UNLOCKED)
+#define rspin_lock_init(l) (*(l) = (rspinlock_t)SPIN_LOCK_UNLOCKED)
 
 void _spin_lock(spinlock_t *lock);
 void _spin_lock_cb(spinlock_t *lock, void (*cb)(void *data), void *data);
-- 
2.35.3


