Re: [PATCH 4/7] sempahore: add a helper for a concurrency limiter
From: Peter Zijlstra
Date: Wed Mar 29 2023 - 06:15:14 EST
On Wed, Mar 29, 2023 at 02:49:43AM -0700, Luis Chamberlain wrote:
> Seems OK to me. Either way works. Should I carry a patch from you for this
> series?
Sure, here goes (still not even compile tested, but what can go wrong,
right :-)
---
Subject: semaphore: Change DEFINE_SEMAPHORE() to take a number argument
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Wed Mar 29 12:06:08 CEST 2023
Fundamentally semaphores are a counted primitive, but
DEFINE_SEMAPHORE() does not expose this and explicitly creates a
binary semaphore.
Provide DEFINE_BINARY_SEMAPHORE() for this case and 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@xxxxxxxxxxxxx>
---
arch/mips/cavium-octeon/setup.c | 2 +-
arch/x86/kernel/cpu/intel.c | 2 +-
drivers/firmware/efi/runtime-wrappers.c | 2 +-
drivers/firmware/efi/vars.c | 2 +-
drivers/macintosh/adb.c | 2 +-
drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 2 +-
drivers/platform/x86/intel/ifs/sysfs.c | 2 +-
drivers/scsi/esas2r/esas2r_ioctl.c | 2 +-
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c | 2 +-
include/linux/semaphore.h | 7 +++++--
kernel/printk/printk.c | 2 +-
net/rxrpc/call_object.c | 6 ++----
12 files changed, 17 insertions(+), 16 deletions(-)
--- 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
static unsigned long long max_memory = ULLONG_MAX;
static unsigned long long reserve_low_mem;
-DEFINE_SEMAPHORE(octeon_bootbus_sem);
+DEFINE_BINARY_SEMAPHORE(octeon_bootbus_sem);
EXPORT_SYMBOL(octeon_bootbus_sem);
static struct octeon_boot_descriptor *octeon_boot_desc_ptr;
--- 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_BINARY_SEMAPHORE(buslock_sem);
#ifdef CONFIG_PROC_SYSCTL
static struct ctl_table sld_sysctls[] = {
--- 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
* 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_BINARY_SEMAPHORE(efi_runtime_lock);
/*
* Expose the EFI runtime lock to the UV platform
--- 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_BINARY_SEMAPHORE(efivars_lock);
static efi_status_t check_var_size(bool nonblocking, u32 attributes,
unsigned long size)
--- 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_BINARY_SEMAPHORE(adb_probe_mutex);
static int sleepy_trackpad;
static int autopoll_devs;
int __adb_probe_sync;
--- 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_BINARY_SEMAPHORE(bnx2x_prev_sem);
static LIST_HEAD(bnx2x_prev_list);
/* Forward declaration */
--- 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_BINARY_SEMAPHORE(ifs_sem);
/*
* The sysfs interface to check additional details of last test
--- 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_BINARY_SEMAPHORE(buffered_ioctl_semaphore);
typedef int (*BUFFERED_IOCTL_CALLBACK)(struct esas2r_adapter *,
struct esas2r_request *,
struct esas2r_sg_context *,
--- 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_BINARY_SEMAPHORE(g_free_fragments_mutex);
static int
vchiq_blocking_bulk_transfer(struct vchiq_instance *instance, unsigned int handle, void *data,
--- a/include/linux/semaphore.h
+++ b/include/linux/semaphore.h
@@ -25,8 +25,11 @@ struct semaphore {
.wait_list = LIST_HEAD_INIT((name).wait_list), \
}
-#define DEFINE_SEMAPHORE(name) \
- struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
+#define DEFINE_SEMAPHORE(_name, _n) \
+ struct semaphore _name = __SEMAPHORE_INITIALIZER(_name, _n)
+
+#define DEFINE_BINARY_SEMAPHORE(_name) \
+ DEFINE_SEMAPHORE(_name, 1)
static inline void sema_init(struct semaphore *sem, int val)
{
--- 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_BINARY_SEMAPHORE(console_sem);
HLIST_HEAD(console_list);
EXPORT_SYMBOL_GPL(console_list);
DEFINE_STATIC_SRCU(console_srcu);
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -40,10 +40,8 @@ const char *const 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)
{