| Message ID | 20241009180719.778285-3-paulmck@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Commit | 599face3b132c18f4b7c1c69a4334f3e586e1e1a |
| Headers | show |
| Series | SRCU-lite changes for v6.13 | expand |
On 10/9/2024 11:37 PM, Paul E. McKenney wrote: > 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> > --- > include/linux/srcu.h | 21 ++++++++++----------- > include/linux/srcutree.h | 2 +- > kernel/rcu/srcutree.c | 22 +++++++++++----------- > 3 files changed, 22 insertions(+), 23 deletions(-) > > diff --git a/include/linux/srcu.h b/include/linux/srcu.h > index 835bbb2d1f88a..06728ef6f32a4 100644 > --- a/include/linux/srcu.h > +++ b/include/linux/srcu.h > @@ -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); As srcu_check_read_flavor() takes an "int" now, passing a macro for the type of reader would be better here? > 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); > } > > diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h > index ed57598394de3..ab7d8d215b84b 100644 > --- a/include/linux/srcutree.h > +++ b/include/linux/srcutree.h > @@ -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? */ This is a mask for the reader flavor, so s/srcu_reader_flavor/srcu_reader_flavor_mask ? - Neeraj > > /* Update-side state. */ > spinlock_t __private lock ____cacheline_internodealigned_in_smp; > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index e29c6cbffbcb0..18f2eae5e14bd 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -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 */ > > /*
On Mon, Oct 14, 2024 at 02:40:35PM +0530, Neeraj Upadhyay wrote: > On 10/9/2024 11:37 PM, Paul E. McKenney wrote: > > 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> > > --- > > include/linux/srcu.h | 21 ++++++++++----------- > > include/linux/srcutree.h | 2 +- > > kernel/rcu/srcutree.c | 22 +++++++++++----------- > > 3 files changed, 22 insertions(+), 23 deletions(-) > > > > diff --git a/include/linux/srcu.h b/include/linux/srcu.h > > index 835bbb2d1f88a..06728ef6f32a4 100644 > > --- a/include/linux/srcu.h > > +++ b/include/linux/srcu.h > > @@ -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); > > As srcu_check_read_flavor() takes an "int" now, passing a macro for the type of reader would > be better here? Agreed, and a later commit does introduce macros. > > 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); > > } > > > > diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h > > index ed57598394de3..ab7d8d215b84b 100644 > > --- a/include/linux/srcutree.h > > +++ b/include/linux/srcutree.h > > @@ -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? */ > > This is a mask for the reader flavor, so s/srcu_reader_flavor/srcu_reader_flavor_mask ? Yes, it is a mask, but one that should only ever have a single bit set. So calling it a mask might or might not be a service to the reader. Thanx, Paul > - Neeraj > > > > > /* Update-side state. */ > > spinlock_t __private lock ____cacheline_internodealigned_in_smp; > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > > index e29c6cbffbcb0..18f2eae5e14bd 100644 > > --- a/kernel/rcu/srcutree.c > > +++ b/kernel/rcu/srcutree.c > > @@ -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 */ > > > > /* >
On 10/14/2024 10:22 PM, Paul E. McKenney wrote: > On Mon, Oct 14, 2024 at 02:40:35PM +0530, Neeraj Upadhyay wrote: >> On 10/9/2024 11:37 PM, Paul E. McKenney wrote: >>> 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> >>> --- >>> include/linux/srcu.h | 21 ++++++++++----------- >>> include/linux/srcutree.h | 2 +- >>> kernel/rcu/srcutree.c | 22 +++++++++++----------- >>> 3 files changed, 22 insertions(+), 23 deletions(-) >>> >>> diff --git a/include/linux/srcu.h b/include/linux/srcu.h >>> index 835bbb2d1f88a..06728ef6f32a4 100644 >>> --- a/include/linux/srcu.h >>> +++ b/include/linux/srcu.h >>> @@ -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); >> >> As srcu_check_read_flavor() takes an "int" now, passing a macro for the type of reader would >> be better here? > > Agreed, and a later commit does introduce macros. > >>> 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); >>> } >>> >>> diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h >>> index ed57598394de3..ab7d8d215b84b 100644 >>> --- a/include/linux/srcutree.h >>> +++ b/include/linux/srcutree.h >>> @@ -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? */ >> >> This is a mask for the reader flavor, so s/srcu_reader_flavor/srcu_reader_flavor_mask ? > > Yes, it is a mask, but one that should only ever have a single bit set. > So calling it a mask might or might not be a service to the reader. > Ok. The usage of reader_flavor as a shifted val here and without shift as arg of srcu_check_read_flavor() was a bit confusing. - Neeraj ... >>> >>> #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 */ >>> >>> /* >>
diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 835bbb2d1f88a..06728ef6f32a4 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -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); } diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h index ed57598394de3..ab7d8d215b84b 100644 --- a/include/linux/srcutree.h +++ b/include/linux/srcutree.h @@ -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; diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index e29c6cbffbcb0..18f2eae5e14bd 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -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 */ /*
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> --- include/linux/srcu.h | 21 ++++++++++----------- include/linux/srcutree.h | 2 +- kernel/rcu/srcutree.c | 22 +++++++++++----------- 3 files changed, 22 insertions(+), 23 deletions(-)