diff options
author | Kent Overstreet <kent.overstreet@linux.dev> | 2023-05-25 17:52:28 -0400 |
---|---|---|
committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-05-25 22:25:34 -0400 |
commit | 1f78fed4693a5361f56508daac59bebd5b556379 (patch) | |
tree | 267c710018040b6caa9193a1ee34e514317709c4 /include | |
parent | b8b8dcfaed641eabeec8ba070e1e23665bc4ceb2 (diff) |
Update bcachefs sources to 31c09369cd six locks: Fix an unitialized var
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/atomic.h | 14 | ||||
-rw-r--r-- | include/linux/mean_and_variance.h | 219 | ||||
-rw-r--r-- | include/linux/six.h | 449 |
3 files changed, 398 insertions, 284 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h index a9852fa1..79cf5aa9 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -32,6 +32,8 @@ typedef struct { #define __ATOMIC_SUB(v, p) uatomic_sub(p, v) #define __ATOMIC_INC(p) uatomic_inc(p) #define __ATOMIC_DEC(p) uatomic_dec(p) +#define __ATOMIC_AND(v, p) uatomic_and(p, v) +#define __ATOMIC_OR(v, p) uatomic_or(p, v) #define xchg(p, v) uatomic_xchg(p, v) #define xchg_acquire(p, v) uatomic_xchg(p, v) @@ -56,6 +58,8 @@ typedef struct { #define __ATOMIC_SUB_RETURN(v, p) __atomic_sub_fetch(p, v, __ATOMIC_RELAXED) #define __ATOMIC_SUB_RETURN_RELEASE(v, p) \ __atomic_sub_fetch(p, v, __ATOMIC_RELEASE) +#define __ATOMIC_AND(p) __atomic_and_fetch(p, v, __ATOMIC_RELAXED) +#define __ATOMIC_OR(p) __atomic_or_fetch(p, v, __ATOMIC_RELAXED) #define xchg(p, v) __atomic_exchange_n(p, v, __ATOMIC_SEQ_CST) #define xchg_acquire(p, v) __atomic_exchange_n(p, v, __ATOMIC_ACQUIRE) @@ -244,6 +248,16 @@ static inline bool a_type##_inc_not_zero(a_type##_t *v) \ return a_type##_add_unless(v, 1, 0); \ } \ \ +static inline void a_type##_and(i_type a, a_type##_t *v) \ +{ \ + __ATOMIC_AND(a, v); \ +} \ + \ +static inline void a_type##_or(i_type a, a_type##_t *v) \ +{ \ + __ATOMIC_OR(a, v); \ +} \ + \ static inline i_type a_type##_xchg(a_type##_t *v, i_type i) \ { \ return xchg(&v->counter, i); \ diff --git a/include/linux/mean_and_variance.h b/include/linux/mean_and_variance.h index 756eb3d1..9ed79f42 100644 --- a/include/linux/mean_and_variance.h +++ b/include/linux/mean_and_variance.h @@ -2,122 +2,112 @@ #ifndef MEAN_AND_VARIANCE_H_ #define MEAN_AND_VARIANCE_H_ -#include <linux/kernel.h> #include <linux/types.h> +#include <linux/kernel.h> #include <linux/limits.h> #include <linux/math64.h> +#include <stdlib.h> #define SQRT_U64_MAX 4294967295ULL -/** - * abs - return absolute value of an argument - * @x: the value. If it is unsigned type, it is converted to signed type first. - * char is treated as if it was signed (regardless of whether it really is) - * but the macro's return type is preserved as char. - * - * Return: an absolute value of x. +/* + * u128_u: u128 user mode, because not all architectures support a real int128 + * type */ -#define abs(x) __abs_choose_expr(x, long long, \ - __abs_choose_expr(x, long, \ - __abs_choose_expr(x, int, \ - __abs_choose_expr(x, short, \ - __abs_choose_expr(x, char, \ - __builtin_choose_expr( \ - __builtin_types_compatible_p(typeof(x), char), \ - (char)({ signed char __x = (x); __x<0?-__x:__x; }), \ - ((void)0))))))) -#define __abs_choose_expr(x, type, other) __builtin_choose_expr( \ - __builtin_types_compatible_p(typeof(x), signed type) || \ - __builtin_types_compatible_p(typeof(x), unsigned type), \ - ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other) +#ifdef __SIZEOF_INT128__ -#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) - -typedef unsigned __int128 u128; +typedef struct { + unsigned __int128 v; +} __aligned(16) u128_u; -static inline u128 u64_to_u128(u64 a) +static inline u128_u u64_to_u128(u64 a) { - return (u128)a; + return (u128_u) { .v = a }; } -static inline u64 u128_to_u64(u128 a) +static inline u64 u128_lo(u128_u a) { - return (u64)a; + return a.v; } -static inline u64 u128_shr64_to_u64(u128 a) +static inline u64 u128_hi(u128_u a) { - return (u64)(a >> 64); + return a.v >> 64; } -static inline u128 u128_add(u128 a, u128 b) +static inline u128_u u128_add(u128_u a, u128_u b) { - return a + b; + a.v += b.v; + return a; } -static inline u128 u128_sub(u128 a, u128 b) +static inline u128_u u128_sub(u128_u a, u128_u b) { - return a - b; + a.v -= b.v; + return a; } -static inline u128 u128_shl(u128 i, s8 shift) +static inline u128_u u128_shl(u128_u a, s8 shift) { - return i << shift; + a.v <<= shift; + return a; } -static inline u128 u128_shl64_add(u64 a, u64 b) +static inline u128_u u128_square(u64 a) { - return ((u128)a << 64) + b; -} + u128_u b = u64_to_u128(a); -static inline u128 u128_square(u64 i) -{ - return i*i; + b.v *= b.v; + return b; } #else typedef struct { u64 hi, lo; -} u128; +} __aligned(16) u128_u; + +/* conversions */ -static inline u128 u64_to_u128(u64 a) +static inline u128_u u64_to_u128(u64 a) { - return (u128){ .lo = a }; + return (u128_u) { .lo = a }; } -static inline u64 u128_to_u64(u128 a) +static inline u64 u128_lo(u128_u a) { return a.lo; } -static inline u64 u128_shr64_to_u64(u128 a) +static inline u64 u128_hi(u128_u a) { return a.hi; } -static inline u128 u128_add(u128 a, u128 b) +/* arithmetic */ + +static inline u128_u u128_add(u128_u a, u128_u b) { - u128 c; + u128_u c; c.lo = a.lo + b.lo; c.hi = a.hi + b.hi + (c.lo < a.lo); return c; } -static inline u128 u128_sub(u128 a, u128 b) +static inline u128_u u128_sub(u128_u a, u128_u b) { - u128 c; + u128_u c; c.lo = a.lo - b.lo; c.hi = a.hi - b.hi - (c.lo > a.lo); return c; } -static inline u128 u128_shl(u128 i, s8 shift) +static inline u128_u u128_shl(u128_u i, s8 shift) { - u128 r; + u128_u r; r.lo = i.lo << shift; if (shift < 64) @@ -129,15 +119,10 @@ static inline u128 u128_shl(u128 i, s8 shift) return r; } -static inline u128 u128_shl64_add(u64 a, u64 b) +static inline u128_u u128_square(u64 i) { - return u128_add(u128_shl(u64_to_u128(a), 64), u64_to_u128(b)); -} - -static inline u128 u128_square(u64 i) -{ - u128 r; - u64 h = i >> 32, l = i & (u64)U32_MAX; + u128_u r; + u64 h = i >> 32, l = i & U32_MAX; r = u128_shl(u64_to_u128(h*h), 64); r = u128_add(r, u128_shl(u64_to_u128(h*l), 32)); @@ -148,85 +133,69 @@ static inline u128 u128_square(u64 i) #endif -static inline u128 u128_div(u128 n, u64 d) +static inline u128_u u64s_to_u128(u64 hi, u64 lo) { - u128 r; - u64 rem; - u64 hi = u128_shr64_to_u64(n); - u64 lo = u128_to_u64(n); - u64 h = hi & ((u64)U32_MAX << 32); - u64 l = (hi & (u64)U32_MAX) << 32; + u128_u c = u64_to_u128(hi); - r = u128_shl(u64_to_u128(div64_u64_rem(h, d, &rem)), 64); - r = u128_add(r, u128_shl(u64_to_u128(div64_u64_rem(l + (rem << 32), d, &rem)), 32)); - r = u128_add(r, u64_to_u128(div64_u64_rem(lo + (rem << 32), d, &rem))); - return r; + c = u128_shl(c, 64); + c = u128_add(c, u64_to_u128(lo)); + return c; } +u128_u u128_div(u128_u n, u64 d); + struct mean_and_variance { - s64 n; - s64 sum; - u128 sum_squares; + s64 n; + s64 sum; + u128_u sum_squares; }; /* expontentially weighted variant */ struct mean_and_variance_weighted { - bool init; - u8 w; - s64 mean; - u64 variance; + bool init; + u8 weight; /* base 2 logarithim */ + s64 mean; + u64 variance; }; -s64 fast_divpow2(s64 n, u8 d); +/** + * fast_divpow2() - fast approximation for n / (1 << d) + * @n: numerator + * @d: the power of 2 denominator. + * + * note: this rounds towards 0. + */ +static inline s64 fast_divpow2(s64 n, u8 d) +{ + return (n + ((n < 0) ? ((1 << d) - 1) : 0)) >> d; +} +/** + * mean_and_variance_update() - update a mean_and_variance struct @s1 with a new sample @v1 + * and return it. + * @s1: the mean_and_variance to update. + * @v1: the new sample. + * + * see linked pdf equation 12. + */ static inline struct mean_and_variance -mean_and_variance_update_inlined(struct mean_and_variance s1, s64 v1) -{ - struct mean_and_variance s2; - u64 v2 = abs(v1); - - s2.n = s1.n + 1; - s2.sum = s1.sum + v1; - s2.sum_squares = u128_add(s1.sum_squares, u128_square(v2)); - return s2; -} - -static inline struct mean_and_variance_weighted -mean_and_variance_weighted_update_inlined(struct mean_and_variance_weighted s1, s64 x) -{ - struct mean_and_variance_weighted s2; - // previous weighted variance. - u64 var_w0 = s1.variance; - u8 w = s2.w = s1.w; - // new value weighted. - s64 x_w = x << w; - s64 diff_w = x_w - s1.mean; - s64 diff = fast_divpow2(diff_w, w); - // new mean weighted. - s64 u_w1 = s1.mean + diff; - - BUG_ON(w % 2 != 0); - - if (!s1.init) { - s2.mean = x_w; - s2.variance = 0; - } else { - s2.mean = u_w1; - s2.variance = ((var_w0 << w) - var_w0 + ((diff_w * (x_w - u_w1)) >> w)) >> w; - } - s2.init = true; - - return s2; +mean_and_variance_update(struct mean_and_variance s, s64 v) +{ + return (struct mean_and_variance) { + .n = s.n + 1, + .sum = s.sum + v, + .sum_squares = u128_add(s.sum_squares, u128_square(abs(v))), + }; } -struct mean_and_variance mean_and_variance_update(struct mean_and_variance s1, s64 v1); - s64 mean_and_variance_get_mean(struct mean_and_variance s); - u64 mean_and_variance_get_variance(struct mean_and_variance s1); - u32 mean_and_variance_get_stddev(struct mean_and_variance s); +s64 mean_and_variance_get_mean(struct mean_and_variance s); +u64 mean_and_variance_get_variance(struct mean_and_variance s1); +u32 mean_and_variance_get_stddev(struct mean_and_variance s); + +void mean_and_variance_weighted_update(struct mean_and_variance_weighted *s, s64 v); -struct mean_and_variance_weighted mean_and_variance_weighted_update(struct mean_and_variance_weighted s1, s64 v1); - s64 mean_and_variance_weighted_get_mean(struct mean_and_variance_weighted s); - u64 mean_and_variance_weighted_get_variance(struct mean_and_variance_weighted s); - u32 mean_and_variance_weighted_get_stddev(struct mean_and_variance_weighted s); +s64 mean_and_variance_weighted_get_mean(struct mean_and_variance_weighted s); +u64 mean_and_variance_weighted_get_variance(struct mean_and_variance_weighted s); +u32 mean_and_variance_weighted_get_stddev(struct mean_and_variance_weighted s); #endif // MEAN_AND_VAIRANCE_H_ diff --git a/include/linux/six.h b/include/linux/six.h index 83023f64..394da423 100644 --- a/include/linux/six.h +++ b/include/linux/six.h @@ -3,59 +3,124 @@ #ifndef _LINUX_SIX_H #define _LINUX_SIX_H -/* - * Shared/intent/exclusive locks: sleepable read/write locks, much like rw - * semaphores, except with a third intermediate state, intent. Basic operations - * are: +/** + * DOC: SIX locks overview * - * six_lock_read(&foo->lock); - * six_unlock_read(&foo->lock); + * Shared/intent/exclusive locks: sleepable read/write locks, like rw semaphores + * but with an additional state: read/shared, intent, exclusive/write * - * six_lock_intent(&foo->lock); - * six_unlock_intent(&foo->lock); + * The purpose of the intent state is to allow for greater concurrency on tree + * structures without deadlocking. In general, a read can't be upgraded to a + * write lock without deadlocking, so an operation that updates multiple nodes + * will have to take write locks for the full duration of the operation. * - * six_lock_write(&foo->lock); - * six_unlock_write(&foo->lock); + * But by adding an intent state, which is exclusive with other intent locks but + * not with readers, we can take intent locks at thte start of the operation, + * and then take write locks only for the actual update to each individual + * nodes, without deadlocking. * - * Intent locks block other intent locks, but do not block read locks, and you - * must have an intent lock held before taking a write lock, like so: + * Example usage: + * six_lock_read(&foo->lock); + * six_unlock_read(&foo->lock); * - * six_lock_intent(&foo->lock); - * six_lock_write(&foo->lock); - * six_unlock_write(&foo->lock); - * six_unlock_intent(&foo->lock); + * An intent lock must be held before taking a write lock: + * six_lock_intent(&foo->lock); + * six_lock_write(&foo->lock); + * six_unlock_write(&foo->lock); + * six_unlock_intent(&foo->lock); * * Other operations: - * * six_trylock_read() * six_trylock_intent() * six_trylock_write() * - * six_lock_downgrade(): convert from intent to read - * six_lock_tryupgrade(): attempt to convert from read to intent - * - * Locks also embed a sequence number, which is incremented when the lock is - * locked or unlocked for write. The current sequence number can be grabbed - * while a lock is held from lock->state.seq; then, if you drop the lock you can - * use six_relock_(read|intent_write)(lock, seq) to attempt to retake the lock - * iff it hasn't been locked for write in the meantime. - * - * There are also operations that take the lock type as a parameter, where the - * type is one of SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write: - * - * six_lock_type(lock, type) - * six_unlock_type(lock, type) - * six_relock(lock, type, seq) - * six_trylock_type(lock, type) - * six_trylock_convert(lock, from, to) - * - * A lock may be held multiple times by the same thread (for read or intent, - * not write). However, the six locks code does _not_ implement the actual - * recursive checks itself though - rather, if your code (e.g. btree iterator - * code) knows that the current thread already has a lock held, and for the - * correct type, six_lock_increment() may be used to bump up the counter for - * that type - the only effect is that one more call to unlock will be required - * before the lock is unlocked. + * six_lock_downgrade() convert from intent to read + * six_lock_tryupgrade() attempt to convert from read to intent, may fail + * + * There are also interfaces that take the lock type as an enum: + * + * six_lock_type(&foo->lock, SIX_LOCK_read); + * six_trylock_convert(&foo->lock, SIX_LOCK_read, SIX_LOCK_intent) + * six_lock_type(&foo->lock, SIX_LOCK_write); + * six_unlock_type(&foo->lock, SIX_LOCK_write); + * six_unlock_type(&foo->lock, SIX_LOCK_intent); + * + * Lock sequence numbers - unlock(), relock(): + * + * Locks embed sequences numbers, which are incremented on write lock/unlock. + * This allows locks to be dropped and the retaken iff the state they protect + * hasn't changed; this makes it much easier to avoid holding locks while e.g. + * doing IO or allocating memory. + * + * Example usage: + * six_lock_read(&foo->lock); + * u32 seq = six_lock_seq(&foo->lock); + * six_unlock_read(&foo->lock); + * + * some_operation_that_may_block(); + * + * if (six_relock_read(&foo->lock, seq)) { ... } + * + * If the relock operation succeeds, it is as if the lock was never unlocked. + * + * Reentrancy: + * + * Six locks are not by themselves reentrent, but have counters for both the + * read and intent states that can be used to provide reentrency by an upper + * layer that tracks held locks. If a lock is known to already be held in the + * read or intent state, six_lock_increment() can be used to bump the "lock + * held in this state" counter, increasing the number of unlock calls that + * will be required to fully unlock it. + * + * Example usage: + * six_lock_read(&foo->lock); + * six_lock_increment(&foo->lock, SIX_LOCK_read); + * six_unlock_read(&foo->lock); + * six_unlock_read(&foo->lock); + * foo->lock is now fully unlocked. + * + * Since the intent state supercedes read, it's legal to increment the read + * counter when holding an intent lock, but not the reverse. + * + * A lock may only be held once for write: six_lock_increment(.., SIX_LOCK_write) + * is not legal. + * + * should_sleep_fn: + * + * There is a six_lock() variant that takes a function pointer that is called + * immediately prior to schedule() when blocking, and may return an error to + * abort. + * + * One possible use for this feature is when objects being locked are part of + * a cache and may reused, and lock ordering is based on a property of the + * object that will change when the object is reused - i.e. logical key order. + * + * If looking up an object in the cache may race with object reuse, and lock + * ordering is required to prevent deadlock, object reuse may change the + * correct lock order for that object and cause a deadlock. should_sleep_fn + * can be used to check if the object is still the object we want and avoid + * this deadlock. + * + * Wait list entry interface: + * + * There is a six_lock() variant, six_lock_waiter(), that takes a pointer to a + * wait list entry. By embedding six_lock_waiter into another object, and by + * traversing lock waitlists, it is then possible for an upper layer to + * implement full cycle detection for deadlock avoidance. + * + * should_sleep_fn should be used for invoking the cycle detector, walking the + * graph of held locks to check for a deadlock. The upper layer must track + * held locks for each thread, and each thread's held locks must be reachable + * from its six_lock_waiter object. + * + * six_lock_waiter() will add the wait object to the waitlist re-trying taking + * the lock, and before calling should_sleep_fn, and the wait object will not + * be removed from the waitlist until either the lock has been successfully + * acquired, or we aborted because should_sleep_fn returned an error. + * + * Also, six_lock_waiter contains a timestamp, and waiters on a waitlist will + * have timestamps in strictly ascending order - this is so the timestamp can + * be used as a cursor for lock graph traverse. */ #include <linux/lockdep.h> @@ -63,41 +128,6 @@ #include <linux/sched.h> #include <linux/types.h> -#define SIX_LOCK_SEPARATE_LOCKFNS - -union six_lock_state { - struct { - atomic64_t counter; - }; - - struct { - u64 v; - }; - - struct { - /* for waitlist_bitnr() */ - unsigned long l; - }; - - struct { - unsigned read_lock:26; - unsigned write_locking:1; - unsigned intent_lock:1; - unsigned nospin:1; - unsigned waiters:3; - /* - * seq works much like in seqlocks: it's incremented every time - * we lock and unlock for write. - * - * If it's odd write lock is held, even unlocked. - * - * Thus readers can unlock, and then lock again later iff it - * hasn't been modified in the meantime. - */ - u32 seq; - }; -}; - enum six_lock_type { SIX_LOCK_read, SIX_LOCK_intent, @@ -105,7 +135,8 @@ enum six_lock_type { }; struct six_lock { - union six_lock_state state; + atomic_t state; + u32 seq; unsigned intent_lock_recurse; struct task_struct *owner; unsigned __percpu *readers; @@ -127,59 +158,210 @@ struct six_lock_waiter { typedef int (*six_lock_should_sleep_fn)(struct six_lock *lock, void *); -static __always_inline void __six_lock_init(struct six_lock *lock, - const char *name, - struct lock_class_key *key) -{ - atomic64_set(&lock->state.counter, 0); - raw_spin_lock_init(&lock->wait_lock); - INIT_LIST_HEAD(&lock->wait_list); -#ifdef CONFIG_DEBUG_LOCK_ALLOC - debug_check_no_locks_freed((void *) lock, sizeof(*lock)); - lockdep_init_map(&lock->dep_map, name, key, 0); -#endif -} +void six_lock_exit(struct six_lock *lock); + +enum six_lock_init_flags { + SIX_LOCK_INIT_PCPU = 1U << 0, +}; -#define six_lock_init(lock) \ +void __six_lock_init(struct six_lock *lock, const char *name, + struct lock_class_key *key, enum six_lock_init_flags flags); + +/** + * six_lock_init - initialize a six lock + * @lock: lock to initialize + * @flags: optional flags, i.e. SIX_LOCK_INIT_PCPU + */ +#define six_lock_init(lock, flags) \ do { \ static struct lock_class_key __key; \ \ - __six_lock_init((lock), #lock, &__key); \ + __six_lock_init((lock), #lock, &__key, flags); \ } while (0) -#define __SIX_VAL(field, _v) (((union six_lock_state) { .field = _v }).v) +/** + * six_lock_seq - obtain current lock sequence number + * @lock: six_lock to obtain sequence number for + * + * @lock should be held for read or intent, and not write + * + * By saving the lock sequence number, we can unlock @lock and then (typically + * after some blocking operation) attempt to relock it: the relock will succeed + * if the sequence number hasn't changed, meaning no write locks have been taken + * and state corresponding to what @lock protects is still valid. + */ +static inline u32 six_lock_seq(const struct six_lock *lock) +{ + return lock->seq; +} + +bool six_trylock_ip(struct six_lock *lock, enum six_lock_type type, unsigned long ip); + +/** + * six_trylock_type - attempt to take a six lock without blocking + * @lock: lock to take + * @type: SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write + * + * Return: true on success, false on failure. + */ +static inline bool six_trylock_type(struct six_lock *lock, enum six_lock_type type) +{ + return six_trylock_ip(lock, type, _THIS_IP_); +} + +int six_lock_ip_waiter(struct six_lock *lock, enum six_lock_type type, + struct six_lock_waiter *wait, + six_lock_should_sleep_fn should_sleep_fn, void *p, + unsigned long ip); + +/** + * six_lock_waiter - take a lock, with full waitlist interface + * @lock: lock to take + * @type: SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write + * @wait: pointer to wait object, which will be added to lock's waitlist + * @should_sleep_fn: callback run after adding to waitlist, immediately prior + * to scheduling + * @p: passed through to @should_sleep_fn + * + * This is a convenience wrapper around six_lock_ip_waiter(), see that function + * for full documentation. + * + * Return: 0 on success, or the return code from @should_sleep_fn on failure. + */ +static inline int six_lock_waiter(struct six_lock *lock, enum six_lock_type type, + struct six_lock_waiter *wait, + six_lock_should_sleep_fn should_sleep_fn, void *p) +{ + return six_lock_ip_waiter(lock, type, wait, should_sleep_fn, p, _THIS_IP_); +} + +/** + * six_lock_ip - take a six lock lock + * @lock: lock to take + * @type: SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write + * @should_sleep_fn: callback run after adding to waitlist, immediately prior + * to scheduling + * @p: passed through to @should_sleep_fn + * @ip: ip parameter for lockdep/lockstat, i.e. _THIS_IP_ + * + * Return: 0 on success, or the return code from @should_sleep_fn on failure. + */ +static inline int six_lock_ip(struct six_lock *lock, enum six_lock_type type, + six_lock_should_sleep_fn should_sleep_fn, void *p, + unsigned long ip) +{ + struct six_lock_waiter wait; + + return six_lock_ip_waiter(lock, type, &wait, should_sleep_fn, p, ip); +} + +/** + * six_lock_type - take a six lock lock + * @lock: lock to take + * @type: SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write + * @should_sleep_fn: callback run after adding to waitlist, immediately prior + * to scheduling + * @p: passed through to @should_sleep_fn + * + * Return: 0 on success, or the return code from @should_sleep_fn on failure. + */ +static inline int six_lock_type(struct six_lock *lock, enum six_lock_type type, + six_lock_should_sleep_fn should_sleep_fn, void *p) +{ + struct six_lock_waiter wait; + + return six_lock_ip_waiter(lock, type, &wait, should_sleep_fn, p, _THIS_IP_); +} + +bool six_relock_ip(struct six_lock *lock, enum six_lock_type type, + unsigned seq, unsigned long ip); + +/** + * six_relock_type - attempt to re-take a lock that was held previously + * @lock: lock to take + * @type: SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write + * @seq: lock sequence number obtained from six_lock_seq() while lock was + * held previously + * + * Return: true on success, false on failure. + */ +static inline bool six_relock_type(struct six_lock *lock, enum six_lock_type type, + unsigned seq) +{ + return six_relock_ip(lock, type, seq, _THIS_IP_); +} + +void six_unlock_ip(struct six_lock *lock, enum six_lock_type type, unsigned long ip); + +/** + * six_unlock_type - drop a six lock + * @lock: lock to unlock + * @type: SIX_LOCK_read, SIX_LOCK_intent, or SIX_LOCK_write + * + * When a lock is held multiple times (because six_lock_incement()) was used), + * this decrements the 'lock held' counter by one. + * + * For example: + * six_lock_read(&foo->lock); read count 1 + * six_lock_increment(&foo->lock, SIX_LOCK_read); read count 2 + * six_lock_unlock(&foo->lock, SIX_LOCK_read); read count 1 + * six_lock_unlock(&foo->lock, SIX_LOCK_read); read count 0 + */ +static inline void six_unlock_type(struct six_lock *lock, enum six_lock_type type) +{ + six_unlock_ip(lock, type, _THIS_IP_); +} #define __SIX_LOCK(type) \ -bool six_trylock_ip_##type(struct six_lock *, unsigned long); \ -bool six_relock_ip_##type(struct six_lock *, u32, unsigned long); \ -int six_lock_ip_##type(struct six_lock *, six_lock_should_sleep_fn, \ - void *, unsigned long); \ -int six_lock_ip_waiter_##type(struct six_lock *, struct six_lock_waiter *,\ - six_lock_should_sleep_fn, void *, unsigned long);\ -void six_unlock_ip_##type(struct six_lock *, unsigned long); \ +static inline bool six_trylock_ip_##type(struct six_lock *lock, unsigned long ip)\ +{ \ + return six_trylock_ip(lock, SIX_LOCK_##type, ip); \ +} \ \ static inline bool six_trylock_##type(struct six_lock *lock) \ { \ - return six_trylock_ip_##type(lock, _THIS_IP_); \ + return six_trylock_ip(lock, SIX_LOCK_##type, _THIS_IP_); \ +} \ + \ +static inline int six_lock_ip_waiter_##type(struct six_lock *lock, \ + struct six_lock_waiter *wait, \ + six_lock_should_sleep_fn should_sleep_fn, void *p,\ + unsigned long ip) \ +{ \ + return six_lock_ip_waiter(lock, SIX_LOCK_##type, wait, should_sleep_fn, p, ip);\ +} \ + \ +static inline int six_lock_ip_##type(struct six_lock *lock, \ + six_lock_should_sleep_fn should_sleep_fn, void *p, \ + unsigned long ip) \ +{ \ + return six_lock_ip(lock, SIX_LOCK_##type, should_sleep_fn, p, ip);\ +} \ + \ +static inline bool six_relock_ip_##type(struct six_lock *lock, u32 seq, unsigned long ip)\ +{ \ + return six_relock_ip(lock, SIX_LOCK_##type, seq, ip); \ } \ + \ static inline bool six_relock_##type(struct six_lock *lock, u32 seq) \ { \ - return six_relock_ip_##type(lock, seq, _THIS_IP_); \ + return six_relock_ip(lock, SIX_LOCK_##type, seq, _THIS_IP_); \ } \ + \ static inline int six_lock_##type(struct six_lock *lock, \ six_lock_should_sleep_fn fn, void *p)\ { \ return six_lock_ip_##type(lock, fn, p, _THIS_IP_); \ } \ -static inline int six_lock_waiter_##type(struct six_lock *lock, \ - struct six_lock_waiter *wait, \ - six_lock_should_sleep_fn fn, void *p) \ + \ +static inline void six_unlock_ip_##type(struct six_lock *lock, unsigned long ip) \ { \ - return six_lock_ip_waiter_##type(lock, wait, fn, p, _THIS_IP_); \ + six_unlock_ip(lock, SIX_LOCK_##type, ip); \ } \ + \ static inline void six_unlock_##type(struct six_lock *lock) \ { \ - return six_unlock_ip_##type(lock, _THIS_IP_); \ + six_unlock_ip(lock, SIX_LOCK_##type, _THIS_IP_); \ } __SIX_LOCK(read) @@ -187,55 +369,6 @@ __SIX_LOCK(intent) __SIX_LOCK(write) #undef __SIX_LOCK -#define SIX_LOCK_DISPATCH(type, fn, ...) \ - switch (type) { \ - case SIX_LOCK_read: \ - return fn##_read(__VA_ARGS__); \ - case SIX_LOCK_intent: \ - return fn##_intent(__VA_ARGS__); \ - case SIX_LOCK_write: \ - return fn##_write(__VA_ARGS__); \ - default: \ - BUG(); \ - } - -static inline bool six_trylock_type(struct six_lock *lock, enum six_lock_type type) -{ - SIX_LOCK_DISPATCH(type, six_trylock, lock); -} - -static inline bool six_relock_type(struct six_lock *lock, enum six_lock_type type, - unsigned seq) -{ - SIX_LOCK_DISPATCH(type, six_relock, lock, seq); -} - -static inline int six_lock_type(struct six_lock *lock, enum six_lock_type type, - six_lock_should_sleep_fn should_sleep_fn, void *p) -{ - SIX_LOCK_DISPATCH(type, six_lock, lock, should_sleep_fn, p); -} - -static inline int six_lock_type_ip_waiter(struct six_lock *lock, enum six_lock_type type, - struct six_lock_waiter *wait, - six_lock_should_sleep_fn should_sleep_fn, void *p, - unsigned long ip) -{ - SIX_LOCK_DISPATCH(type, six_lock_ip_waiter, lock, wait, should_sleep_fn, p, ip); -} - -static inline int six_lock_type_waiter(struct six_lock *lock, enum six_lock_type type, - struct six_lock_waiter *wait, - six_lock_should_sleep_fn should_sleep_fn, void *p) -{ - SIX_LOCK_DISPATCH(type, six_lock_waiter, lock, wait, should_sleep_fn, p); -} - -static inline void six_unlock_type(struct six_lock *lock, enum six_lock_type type) -{ - SIX_LOCK_DISPATCH(type, six_unlock, lock); -} - void six_lock_downgrade(struct six_lock *); bool six_lock_tryupgrade(struct six_lock *); bool six_trylock_convert(struct six_lock *, enum six_lock_type, @@ -245,13 +378,11 @@ void six_lock_increment(struct six_lock *, enum six_lock_type); void six_lock_wakeup_all(struct six_lock *); -void six_lock_pcpu_free(struct six_lock *); -void six_lock_pcpu_alloc(struct six_lock *); - struct six_lock_count { unsigned n[3]; }; struct six_lock_count six_lock_counts(struct six_lock *); +void six_lock_readers_add(struct six_lock *, int); #endif /* _LINUX_SIX_H */ |