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srcu: Renaming in preparation for additional reader flavor

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Currently, there are only two flavors of readers, normal and NMI-safe.
A number of fields, functions, and types reflect this restriction.
This renaming-only commit prepares for the addition of light-weight
(as in memory-barrier-free) readers.  OK, OK, there is also a drive-by
white-space fixeup!

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Reviewed-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This commit is contained in:
Paul E. McKenney 2024-10-15 09:11:00 -07:00 committed by Frederic Weisbecker
parent e3d6718677
commit 365f34483b
3 changed files with 22 additions and 23 deletions
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21
include/linux/srcu.h
View File

@ -181,10 +181,9 @@ static inline int srcu_read_lock_held(const struct srcu_struct *ssp)
#define SRCU_NMI_SAFE 0x2
#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_TREE_SRCU)
void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe);
void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);
#else
static inline void srcu_check_nmi_safety(struct srcu_struct *ssp,
bool nmi_safe) { }
static inline void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor) { }
#endif
@ -245,7 +244,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
srcu_check_nmi_safety(ssp, false);
srcu_check_read_flavor(ssp, false);
retval = __srcu_read_lock(ssp);
srcu_lock_acquire(&ssp->dep_map);
return retval;
@ -262,7 +261,7 @@ static inline int srcu_read_lock_nmisafe(struct srcu_struct *ssp) __acquires(ssp
{
int retval;
srcu_check_nmi_safety(ssp, true);
srcu_check_read_flavor(ssp, true);
retval = __srcu_read_lock_nmisafe(ssp);
rcu_try_lock_acquire(&ssp->dep_map);
return retval;
@ -274,7 +273,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
{
int retval;
srcu_check_nmi_safety(ssp, false);
srcu_check_read_flavor(ssp, false);
retval = __srcu_read_lock(ssp);
return retval;
}
@ -303,7 +302,7 @@ srcu_read_lock_notrace(struct srcu_struct *ssp) __acquires(ssp)
static inline int srcu_down_read(struct srcu_struct *ssp) __acquires(ssp)
{
WARN_ON_ONCE(in_nmi());
srcu_check_nmi_safety(ssp, false);
srcu_check_read_flavor(ssp, false);
return __srcu_read_lock(ssp);
}
@ -318,7 +317,7 @@ static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx)
__releases(ssp)
{
WARN_ON_ONCE(idx & ~0x1);
srcu_check_nmi_safety(ssp, false);
srcu_check_read_flavor(ssp, false);
srcu_lock_release(&ssp->dep_map);
__srcu_read_unlock(ssp, idx);
}
@ -334,7 +333,7 @@ static inline void srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
__releases(ssp)
{
WARN_ON_ONCE(idx & ~0x1);
srcu_check_nmi_safety(ssp, true);
srcu_check_read_flavor(ssp, true);
rcu_lock_release(&ssp->dep_map);
__srcu_read_unlock_nmisafe(ssp, idx);
}
@ -343,7 +342,7 @@ static inline void srcu_read_unlock_nmisafe(struct srcu_struct *ssp, int idx)
static inline notrace void
srcu_read_unlock_notrace(struct srcu_struct *ssp, int idx) __releases(ssp)
{
srcu_check_nmi_safety(ssp, false);
srcu_check_read_flavor(ssp, false);
__srcu_read_unlock(ssp, idx);
}
@ -360,7 +359,7 @@ static inline void srcu_up_read(struct srcu_struct *ssp, int idx)
{
WARN_ON_ONCE(idx & ~0x1);
WARN_ON_ONCE(in_nmi());
srcu_check_nmi_safety(ssp, false);
srcu_check_read_flavor(ssp, false);
__srcu_read_unlock(ssp, idx);
}

2
include/linux/srcutree.h
View File

@ -25,7 +25,7 @@ struct srcu_data {
/* Read-side state. */
atomic_long_t srcu_lock_count[2]; /* Locks per CPU. */
atomic_long_t srcu_unlock_count[2]; /* Unlocks per CPU. */
int srcu_nmi_safety; /* NMI-safe srcu_struct structure? */
int srcu_reader_flavor; /* Reader flavor for srcu_struct structure? */
/* Update-side state. */
spinlock_t __private lock ____cacheline_internodealigned_in_smp;

22
kernel/rcu/srcutree.c
View File

@ -460,7 +460,7 @@ static unsigned long srcu_readers_unlock_idx(struct srcu_struct *ssp, int idx)
sum += atomic_long_read(&cpuc->srcu_unlock_count[idx]);
if (IS_ENABLED(CONFIG_PROVE_RCU))
mask = mask | READ_ONCE(cpuc->srcu_nmi_safety);
mask = mask | READ_ONCE(cpuc->srcu_reader_flavor);
}
WARN_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && (mask & (mask >> 1)),
"Mixed NMI-safe readers for srcu_struct at %ps.\n", ssp);
@ -699,25 +699,25 @@ EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
#ifdef CONFIG_PROVE_RCU
/*
* Check for consistent NMI safety.
* Check for consistent reader flavor.
*/
void srcu_check_nmi_safety(struct srcu_struct *ssp, bool nmi_safe)
void srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor)
{
int nmi_safe_mask = 1 << nmi_safe;
int old_nmi_safe_mask;
int reader_flavor_mask = 1 << read_flavor;
int old_reader_flavor_mask;
struct srcu_data *sdp;
/* NMI-unsafe use in NMI is a bad sign */
WARN_ON_ONCE(!nmi_safe && in_nmi());
WARN_ON_ONCE(!read_flavor && in_nmi());
sdp = raw_cpu_ptr(ssp->sda);
old_nmi_safe_mask = READ_ONCE(sdp->srcu_nmi_safety);
if (!old_nmi_safe_mask) {
WRITE_ONCE(sdp->srcu_nmi_safety, nmi_safe_mask);
old_reader_flavor_mask = READ_ONCE(sdp->srcu_reader_flavor);
if (!old_reader_flavor_mask) {
WRITE_ONCE(sdp->srcu_reader_flavor, reader_flavor_mask);
return;
}
WARN_ONCE(old_nmi_safe_mask != nmi_safe_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_nmi_safe_mask, nmi_safe_mask);
WARN_ONCE(old_reader_flavor_mask != reader_flavor_mask, "CPU %d old state %d new state %d\n", sdp->cpu, old_reader_flavor_mask, reader_flavor_mask);
}
EXPORT_SYMBOL_GPL(srcu_check_nmi_safety);
EXPORT_SYMBOL_GPL(srcu_check_read_flavor);
#endif /* CONFIG_PROVE_RCU */
/*