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Change DEFINE_SEMAPHORE() to take a number argument

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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>
This commit is contained in:
Peter Zijlstra 2023-03-29 12:14:42 +02:00 committed by Luis Chamberlain
parent 430bb0d1c3
commit 48380368de
12 changed files with 20 additions and 16 deletions
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2
arch/mips/cavium-octeon/setup.c
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@ -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;

2
arch/x86/kernel/cpu/intel.c
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@ -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[] = {

2
drivers/firmware/efi/runtime-wrappers.c
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@ -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

2
drivers/firmware/efi/vars.c
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@ -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)

2
drivers/macintosh/adb.c
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@ -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;

2
drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
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@ -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 */

2
drivers/platform/x86/intel/ifs/sysfs.c
View File

@ -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

2
drivers/scsi/esas2r/esas2r_ioctl.c
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@ -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 *,

2
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
View File

@ -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,

10
include/linux/semaphore.h
View File

@ -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)
{

2
kernel/printk/printk.c
View File

@ -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);

6
net/rxrpc/call_object.c
View File

@ -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)
{