Change DEFINE_SEMAPHORE() to take a number argument

Fundamentally semaphores are a counted primitive, but
DEFINE_SEMAPHORE() does not expose this and explicitly creates a
binary semaphore.

Change DEFINE_SEMAPHORE() to take a number argument and use that in the
few places that open-coded it using __SEMAPHORE_INITIALIZER().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[mcgrof: add some tribal knowledge about why some folks prefer
 binary sempahores over mutexes]
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c
index a71727f7a608c0133b066ab4d6e0a7973a95a344..c5561016f5773bd0c1c754007cb98790548e532d 100644 (file)
--- a/arch/mips/cavium-octeon/setup.c
+++ b/arch/mips/cavium-octeon/setup.c
@@ -72,7 +72,7 @@ extern void pci_console_init(const char *arg);
 static unsigned long long max_memory = ULLONG_MAX;
 static unsigned long long reserve_low_mem;
 
-DEFINE_SEMAPHORE(octeon_bootbus_sem);
+DEFINE_SEMAPHORE(octeon_bootbus_sem, 1);
 EXPORT_SYMBOL(octeon_bootbus_sem);
 
 static struct octeon_boot_descriptor *octeon_boot_desc_ptr;

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 291d4167fab841f371c552cabffca7a84f2d9324..12bad63822f0f25d7f43826e032243679fabc53b 100644 (file)
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1177,7 +1177,7 @@ static const struct {
 static struct ratelimit_state bld_ratelimit;
 
 static unsigned int sysctl_sld_mitigate = 1;
-static DEFINE_SEMAPHORE(buslock_sem);
+static DEFINE_SEMAPHORE(buslock_sem, 1);
 
 #ifdef CONFIG_PROC_SYSCTL
 static struct ctl_table sld_sysctls[] = {

diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c
index 1fba4e09cdcff8f02c8daaaff8127da66bbd8942..a400c4312c829f18ceacb05ead50426472164504 100644 (file)
--- a/drivers/firmware/efi/runtime-wrappers.c
+++ b/drivers/firmware/efi/runtime-wrappers.c
@@ -158,7 +158,7 @@ void efi_call_virt_check_flags(unsigned long flags, const char *call)
  * none of the remaining functions are actually ever called at runtime.
  * So let's just use a single lock to serialize all Runtime Services calls.
  */
-static DEFINE_SEMAPHORE(efi_runtime_lock);
+static DEFINE_SEMAPHORE(efi_runtime_lock, 1);
 
 /*
  * Expose the EFI runtime lock to the UV platform

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index bd75b87f5fc1602d0d2da423e4aa3b372a3e08e4..bfc5fa6aa47b687cc43623b3a238d8564ac1565e 100644 (file)
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -21,7 +21,7 @@
 /* Private pointer to registered efivars */
 static struct efivars *__efivars;
 
-static DEFINE_SEMAPHORE(efivars_lock);
+static DEFINE_SEMAPHORE(efivars_lock, 1);
 
 static efi_status_t check_var_size(bool nonblocking, u32 attributes,
                                   unsigned long size)

diff --git a/drivers/macintosh/adb.c b/drivers/macintosh/adb.c
index 23bd0c77ac1af3b279df00122e606364304057c5..56599515d51aeab1709bb9a59a4876493ae847bb 100644 (file)
--- a/drivers/macintosh/adb.c
+++ b/drivers/macintosh/adb.c
@@ -80,7 +80,7 @@ static struct adb_driver *adb_controller;
 BLOCKING_NOTIFIER_HEAD(adb_client_list);
 static int adb_got_sleep;
 static int adb_inited;
-static DEFINE_SEMAPHORE(adb_probe_mutex);
+static DEFINE_SEMAPHORE(adb_probe_mutex, 1);
 static int sleepy_trackpad;
 static int autopoll_devs;
 int __adb_probe_sync;

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
index 5d1e4fe335aaaa2c805583fcf72a03b4efcc1982..5a105bab43872cd716b77fa07941f97e38a23a16 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -298,7 +298,7 @@ const u32 dmae_reg_go_c[] = {
 
 /* Global resources for unloading a previously loaded device */
 #define BNX2X_PREV_WAIT_NEEDED 1
-static DEFINE_SEMAPHORE(bnx2x_prev_sem);
+static DEFINE_SEMAPHORE(bnx2x_prev_sem, 1);
 static LIST_HEAD(bnx2x_prev_list);
 
 /* Forward declaration */

diff --git a/drivers/platform/x86/intel/ifs/sysfs.c b/drivers/platform/x86/intel/ifs/sysfs.c
index ee636a76b083ab26d3afa956307a9d3c38f3babb..4c3c642ee19a8028b1f029b0f1406f948a91d050 100644 (file)
--- a/drivers/platform/x86/intel/ifs/sysfs.c
+++ b/drivers/platform/x86/intel/ifs/sysfs.c
@@ -13,7 +13,7 @@
  * Protects against simultaneous tests on multiple cores, or
  * reloading can file while a test is in progress
  */
-static DEFINE_SEMAPHORE(ifs_sem);
+static DEFINE_SEMAPHORE(ifs_sem, 1);
 
 /*
  * The sysfs interface to check additional details of last test

diff --git a/drivers/scsi/esas2r/esas2r_ioctl.c b/drivers/scsi/esas2r/esas2r_ioctl.c
index e003d923acbff6777452ecc10088c212c58ddf92..055d2e87a2c8da7ea6ff0b75dafe5eabc9e05da1 100644 (file)
--- a/drivers/scsi/esas2r/esas2r_ioctl.c
+++ b/drivers/scsi/esas2r/esas2r_ioctl.c
@@ -56,7 +56,7 @@ dma_addr_t esas2r_buffered_ioctl_addr;
 u32 esas2r_buffered_ioctl_size;
 struct pci_dev *esas2r_buffered_ioctl_pcid;
 
-static DEFINE_SEMAPHORE(buffered_ioctl_semaphore);
+static DEFINE_SEMAPHORE(buffered_ioctl_semaphore, 1);
 typedef int (*BUFFERED_IOCTL_CALLBACK)(struct esas2r_adapter *,
                                       struct esas2r_request *,
                                       struct esas2r_sg_context *,

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index cddcd3c596c937b1048d6d8c395783ec53084d4c..1a656fdc944556234e085798263c417cce149850 100644 (file)
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -149,7 +149,7 @@ static char *g_fragments_base;
 static char *g_free_fragments;
 static struct semaphore g_free_fragments_sema;
 
-static DEFINE_SEMAPHORE(g_free_fragments_mutex);
+static DEFINE_SEMAPHORE(g_free_fragments_mutex, 1);
 
 static int
 vchiq_blocking_bulk_transfer(struct vchiq_instance *instance, unsigned int handle, void *data,

diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h
index 6694d0019a682dfdf8cc62257b3597958dd49d26..04655faadc2da198d331b436599e45f25efdd8f7 100644 (file)
--- a/include/linux/semaphore.h
+++ b/include/linux/semaphore.h
@@ -25,8 +25,14 @@ struct semaphore {
        .wait_list      = LIST_HEAD_INIT((name).wait_list),             \
 }
 
-#define DEFINE_SEMAPHORE(name) \
-       struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
+/*
+ * Unlike mutexes, binary semaphores do not have an owner, so up() can
+ * be called in a different thread from the one which called down().
+ * It is also safe to call down_trylock() and up() from interrupt
+ * context.
+ */
+#define DEFINE_SEMAPHORE(_name, _n)    \
+       struct semaphore _name = __SEMAPHORE_INITIALIZER(_name, _n)
 
 static inline void sema_init(struct semaphore *sem, int val)
 {

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index fd0c9f913940acf3675cae278465b70ec76c4a87..76987aaa5a452b41403df9601cd5bb6a65441fec 100644 (file)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -89,7 +89,7 @@ static DEFINE_MUTEX(console_mutex);
  * console_sem protects updates to console->seq and console_suspended,
  * and also provides serialization for console printing.
  */
-static DEFINE_SEMAPHORE(console_sem);
+static DEFINE_SEMAPHORE(console_sem, 1);
 HLIST_HEAD(console_list);
 EXPORT_SYMBOL_GPL(console_list);
 DEFINE_STATIC_SRCU(console_srcu);

diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index e9f1f49d18c2a4dcb75da510cbffbbf90af3cf47..3e5cc70884dd91492d9d910a7750755bffa8708c 100644 (file)
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -40,10 +40,8 @@ const char *const rxrpc_call_completions[NR__RXRPC_CALL_COMPLETIONS] = {
 
 struct kmem_cache *rxrpc_call_jar;
 
-static struct semaphore rxrpc_call_limiter =
-       __SEMAPHORE_INITIALIZER(rxrpc_call_limiter, 1000);
-static struct semaphore rxrpc_kernel_call_limiter =
-       __SEMAPHORE_INITIALIZER(rxrpc_kernel_call_limiter, 1000);
+static DEFINE_SEMAPHORE(rxrpc_call_limiter, 1000);
+static DEFINE_SEMAPHORE(rxrpc_kernel_call_limiter, 1000);
 
 void rxrpc_poke_call(struct rxrpc_call *call, enum rxrpc_call_poke_trace what)
 {