* [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance @ 2014-11-26 16:15 Loic Pefferkorn 2014-11-26 20:54 ` Greg KH 0 siblings, 1 reply; 9+ messages in thread From: Loic Pefferkorn @ 2014-11-26 16:15 UTC (permalink / raw) To: oleg.drokin, andreas.dilger, gregkh, gdonald, keith.mannthey, john.hammond Cc: devel, HPDD-discuss, linux-kernel Add __acquires() and __releases() function annotations, to fix sparse warnings related to lock context imbalance. This fixes the following warnings: drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c:153:5: warning: context imbalance in 'cfs_trace_lock_tcd' - wrong count at exit drivers/staging/lustre/lustre/libcfs/hash.c:128:1: warning: context imbalance in 'cfs_hash_spin_lock' - wrong count at exit drivers/staging/lustre/lustre/libcfs/hash.c:142:9: warning: context imbalance in 'cfs_hash_rw_lock' - wrong count at exit drivers/staging/lustre/lustre/ptlrpc/../../lustre/ldlm/l_lock.c:57:17: warning: context imbalance in 'lock_res_and_lock' - wrong count at exit drivers/staging/lustre/lustre/libcfs/libcfs_lock.c:93:1: warning: context imbalance in 'cfs_percpt_lock' - wrong count at exit Signed-off-by: Loic Pefferkorn <loic@loicp.eu> --- drivers/staging/lustre/lustre/libcfs/hash.c | 4 ++++ drivers/staging/lustre/lustre/libcfs/libcfs_lock.c | 2 ++ drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c | 2 ++ drivers/staging/lustre/lustre/obdclass/cl_object.c | 2 ++ 4 files changed, 10 insertions(+) diff --git a/drivers/staging/lustre/lustre/libcfs/hash.c b/drivers/staging/lustre/lustre/libcfs/hash.c index 32da783..7c6e2a3 100644 --- a/drivers/staging/lustre/lustre/libcfs/hash.c +++ b/drivers/staging/lustre/lustre/libcfs/hash.c @@ -126,18 +126,21 @@ cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {} static inline void cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive) + __acquires(&lock->spin) { spin_lock(&lock->spin); } static inline void cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive) + __releases(&lock->spin) { spin_unlock(&lock->spin); } static inline void cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) + __acquires(&lock->rw) { if (!exclusive) read_lock(&lock->rw); @@ -147,6 +150,7 @@ cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) static inline void cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive) + __releases(&lock->rw) { if (!exclusive) read_unlock(&lock->rw); diff --git a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c index 2c199c7..1e529fc 100644 --- a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c +++ b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c @@ -91,6 +91,7 @@ EXPORT_SYMBOL(cfs_percpt_lock_alloc); */ void cfs_percpt_lock(struct cfs_percpt_lock *pcl, int index) + __acquires(pcl->pcl_locks[index]) { int ncpt = cfs_cpt_number(pcl->pcl_cptab); int i; @@ -125,6 +126,7 @@ EXPORT_SYMBOL(cfs_percpt_lock); /** unlock a CPU partition */ void cfs_percpt_unlock(struct cfs_percpt_lock *pcl, int index) + __releases(pcl->pcl_locks[index]) { int ncpt = cfs_cpt_number(pcl->pcl_cptab); int i; diff --git a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c index 976c61e..257669b 100644 --- a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c +++ b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c @@ -151,6 +151,7 @@ cfs_trace_buf_type_t cfs_trace_buf_idx_get(void) * for details. */ int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) + __acquires(&tcd->tc_lock) { __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) @@ -165,6 +166,7 @@ int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) } void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking) + __releases(&tcd->tcd_lock) { __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c index ce96bd2..8577f97 100644 --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c @@ -193,6 +193,7 @@ static spinlock_t *cl_object_attr_guard(struct cl_object *o) * cl_object_attr_get(), cl_object_attr_set(). */ void cl_object_attr_lock(struct cl_object *o) + __acquires(cl_object_attr_guard(o)) { spin_lock(cl_object_attr_guard(o)); } @@ -202,6 +203,7 @@ EXPORT_SYMBOL(cl_object_attr_lock); * Releases data-attributes lock, acquired by cl_object_attr_lock(). */ void cl_object_attr_unlock(struct cl_object *o) + __releases(cl_object_attr_guard(o)) { spin_unlock(cl_object_attr_guard(o)); } -- 2.1.2 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-26 16:15 [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance Loic Pefferkorn @ 2014-11-26 20:54 ` Greg KH 2014-11-27 5:30 ` Loïc Pefferkorn 2014-11-27 18:34 ` Loïc Pefferkorn 0 siblings, 2 replies; 9+ messages in thread From: Greg KH @ 2014-11-26 20:54 UTC (permalink / raw) To: oleg.drokin, andreas.dilger, gdonald, keith.mannthey, john.hammond, devel, HPDD-discuss, linux-kernel On Wed, Nov 26, 2014 at 05:15:48PM +0100, Loic Pefferkorn wrote: > Add __acquires() and __releases() function annotations, to fix sparse warnings related to lock context imbalance. > > This fixes the following warnings: > > drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c:153:5: warning: context imbalance in 'cfs_trace_lock_tcd' - wrong count at exit > drivers/staging/lustre/lustre/libcfs/hash.c:128:1: warning: context imbalance in 'cfs_hash_spin_lock' - wrong count at exit > drivers/staging/lustre/lustre/libcfs/hash.c:142:9: warning: context imbalance in 'cfs_hash_rw_lock' - wrong count at exit > drivers/staging/lustre/lustre/ptlrpc/../../lustre/ldlm/l_lock.c:57:17: warning: context imbalance in 'lock_res_and_lock' - wrong count at exit > drivers/staging/lustre/lustre/libcfs/libcfs_lock.c:93:1: warning: context imbalance in 'cfs_percpt_lock' - wrong count at exit > > Signed-off-by: Loic Pefferkorn <loic@loicp.eu> > --- > drivers/staging/lustre/lustre/libcfs/hash.c | 4 ++++ > drivers/staging/lustre/lustre/libcfs/libcfs_lock.c | 2 ++ > drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c | 2 ++ > drivers/staging/lustre/lustre/obdclass/cl_object.c | 2 ++ > 4 files changed, 10 insertions(+) > > diff --git a/drivers/staging/lustre/lustre/libcfs/hash.c b/drivers/staging/lustre/lustre/libcfs/hash.c > index 32da783..7c6e2a3 100644 > --- a/drivers/staging/lustre/lustre/libcfs/hash.c > +++ b/drivers/staging/lustre/lustre/libcfs/hash.c > @@ -126,18 +126,21 @@ cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {} > > static inline void > cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive) > + __acquires(&lock->spin) > { > spin_lock(&lock->spin); > } > > static inline void > cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive) > + __releases(&lock->spin) > { > spin_unlock(&lock->spin); > } Ugh, how horrid, please just delete these functions and push down the spin_lock/unlock calls down into the places these are called. > > static inline void > cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) > + __acquires(&lock->rw) > { > if (!exclusive) > read_lock(&lock->rw); > @@ -147,6 +150,7 @@ cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) > > static inline void > cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive) > + __releases(&lock->rw) > { > if (!exclusive) > read_unlock(&lock->rw); Same for these. > diff --git a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > index 2c199c7..1e529fc 100644 > --- a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > +++ b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > @@ -91,6 +91,7 @@ EXPORT_SYMBOL(cfs_percpt_lock_alloc); > */ > void > cfs_percpt_lock(struct cfs_percpt_lock *pcl, int index) > + __acquires(pcl->pcl_locks[index]) > { > int ncpt = cfs_cpt_number(pcl->pcl_cptab); > int i; > @@ -125,6 +126,7 @@ EXPORT_SYMBOL(cfs_percpt_lock); > /** unlock a CPU partition */ > void > cfs_percpt_unlock(struct cfs_percpt_lock *pcl, int index) > + __releases(pcl->pcl_locks[index]) > { > int ncpt = cfs_cpt_number(pcl->pcl_cptab); > int i; > diff --git a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > index 976c61e..257669b 100644 > --- a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > +++ b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > @@ -151,6 +151,7 @@ cfs_trace_buf_type_t cfs_trace_buf_idx_get(void) > * for details. > */ > int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > + __acquires(&tcd->tc_lock) > { > __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); > if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) > @@ -165,6 +166,7 @@ int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > } > > void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > + __releases(&tcd->tcd_lock) > { > __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); > if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) > diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c > index ce96bd2..8577f97 100644 > --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c > +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c > @@ -193,6 +193,7 @@ static spinlock_t *cl_object_attr_guard(struct cl_object *o) > * cl_object_attr_get(), cl_object_attr_set(). > */ > void cl_object_attr_lock(struct cl_object *o) > + __acquires(cl_object_attr_guard(o)) > { > spin_lock(cl_object_attr_guard(o)); > } > @@ -202,6 +203,7 @@ EXPORT_SYMBOL(cl_object_attr_lock); > * Releases data-attributes lock, acquired by cl_object_attr_lock(). > */ > void cl_object_attr_unlock(struct cl_object *o) > + __releases(cl_object_attr_guard(o)) > { > spin_unlock(cl_object_attr_guard(o)); > } Same thing here. ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-26 20:54 ` Greg KH @ 2014-11-27 5:30 ` Loïc Pefferkorn 2014-11-27 18:34 ` Loïc Pefferkorn 1 sibling, 0 replies; 9+ messages in thread From: Loïc Pefferkorn @ 2014-11-27 5:30 UTC (permalink / raw) To: Greg KH Cc: oleg.drokin, andreas.dilger, gdonald, keith.mannthey, john.hammond, devel, HPDD-discuss, linux-kernel On Wed, Nov 26, 2014 at 12:54:43PM -0800, Greg KH wrote: > > Ugh, how horrid, please just delete these functions and push down the > spin_lock/unlock calls down into the places these are called. > > Same for these. > > Same thing here. Hello Greg, Thanks for your comments, I will write a v2. -- Cheers, Loic ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-26 20:54 ` Greg KH 2014-11-27 5:30 ` Loïc Pefferkorn @ 2014-11-27 18:34 ` Loïc Pefferkorn 2014-11-28 10:00 ` Dan Carpenter 2014-11-28 22:22 ` Greg KH 1 sibling, 2 replies; 9+ messages in thread From: Loïc Pefferkorn @ 2014-11-27 18:34 UTC (permalink / raw) To: Greg KH Cc: oleg.drokin, andreas.dilger, gdonald, keith.mannthey, john.hammond, devel, HPDD-discuss, linux-kernel Hello Greg, After some investigation, I think that removing these wrappers is not going to improve the code readability: On Wed, Nov 26, 2014 at 12:54:43PM -0800, Greg KH wrote: > On Wed, Nov 26, 2014 at 05:15:48PM +0100, Loic Pefferkorn wrote: > > Add __acquires() and __releases() function annotations, to fix sparse warnings related to lock context imbalance. > > > > This fixes the following warnings: > > > > drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c:153:5: warning: context imbalance in 'cfs_trace_lock_tcd' - wrong count at exit > > drivers/staging/lustre/lustre/libcfs/hash.c:128:1: warning: context imbalance in 'cfs_hash_spin_lock' - wrong count at exit > > drivers/staging/lustre/lustre/libcfs/hash.c:142:9: warning: context imbalance in 'cfs_hash_rw_lock' - wrong count at exit > > drivers/staging/lustre/lustre/ptlrpc/../../lustre/ldlm/l_lock.c:57:17: warning: context imbalance in 'lock_res_and_lock' - wrong count at exit > > drivers/staging/lustre/lustre/libcfs/libcfs_lock.c:93:1: warning: context imbalance in 'cfs_percpt_lock' - wrong count at exit > > > > Signed-off-by: Loic Pefferkorn <loic@loicp.eu> > > --- > > drivers/staging/lustre/lustre/libcfs/hash.c | 4 ++++ > > drivers/staging/lustre/lustre/libcfs/libcfs_lock.c | 2 ++ > > drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c | 2 ++ > > drivers/staging/lustre/lustre/obdclass/cl_object.c | 2 ++ > > 4 files changed, 10 insertions(+) > > > > diff --git a/drivers/staging/lustre/lustre/libcfs/hash.c b/drivers/staging/lustre/lustre/libcfs/hash.c > > index 32da783..7c6e2a3 100644 > > --- a/drivers/staging/lustre/lustre/libcfs/hash.c > > +++ b/drivers/staging/lustre/lustre/libcfs/hash.c > > @@ -126,18 +126,21 @@ cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {} > > > > static inline void > > cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive) > > + __acquires(&lock->spin) > > { > > spin_lock(&lock->spin); > > } > > > > static inline void > > cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive) > > + __releases(&lock->spin) > > { > > spin_unlock(&lock->spin); > > } > > Ugh, how horrid, please just delete these functions and push down the > spin_lock/unlock calls down into the places these are called. cfs_hash_spin_lock() and cfs_hash_spin_unlock() are referenced by function pointers later in the same file: 165 /** no bucket lock, one spinlock to protect everything */ 166 static cfs_hash_lock_ops_t cfs_hash_nbl_lops = { 167 .hs_lock = cfs_hash_spin_lock, 168 .hs_unlock = cfs_hash_spin_unlock, 169 .hs_bkt_lock = cfs_hash_nl_lock, 170 .hs_bkt_unlock = cfs_hash_nl_unlock, 171 }; 172 173 /** spin bucket lock, rehash is enabled */ 174 static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops = { 175 .hs_lock = cfs_hash_rw_lock, 176 .hs_unlock = cfs_hash_rw_unlock, 177 .hs_bkt_lock = cfs_hash_spin_lock, 178 .hs_bkt_unlock = cfs_hash_spin_unlock, 179 }; > > > > > static inline void > > cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) > > + __acquires(&lock->rw) > > { > > if (!exclusive) > > read_lock(&lock->rw); > > @@ -147,6 +150,7 @@ cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) > > > > static inline void > > cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive) > > + __releases(&lock->rw) > > { > > if (!exclusive) > > read_unlock(&lock->rw); > > > Same for these. Likewise for cfs_hash_rw_lock() and cfs_hash_rw_unlock(): 173 /** spin bucket lock, rehash is enabled */ 174 static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops = { 175 .hs_lock = cfs_hash_rw_lock, 176 .hs_unlock = cfs_hash_rw_unlock, 177 .hs_bkt_lock = cfs_hash_spin_lock, 178 .hs_bkt_unlock = cfs_hash_spin_unlock, 179 }; 180 181 /** rw bucket lock, rehash is enabled */ 182 static cfs_hash_lock_ops_t cfs_hash_bkt_rw_lops = { 183 .hs_lock = cfs_hash_rw_lock, 184 .hs_unlock = cfs_hash_rw_unlock, 185 .hs_bkt_lock = cfs_hash_rw_lock, 186 .hs_bkt_unlock = cfs_hash_rw_unlock, 187 }; > > > diff --git a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > > index 2c199c7..1e529fc 100644 > > --- a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > > +++ b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > > @@ -91,6 +91,7 @@ EXPORT_SYMBOL(cfs_percpt_lock_alloc); > > */ > > void > > cfs_percpt_lock(struct cfs_percpt_lock *pcl, int index) > > + __acquires(pcl->pcl_locks[index]) > > { > > int ncpt = cfs_cpt_number(pcl->pcl_cptab); > > int i; > > @@ -125,6 +126,7 @@ EXPORT_SYMBOL(cfs_percpt_lock); > > /** unlock a CPU partition */ > > void > > cfs_percpt_unlock(struct cfs_percpt_lock *pcl, int index) > > + __releases(pcl->pcl_locks[index]) > > { > > int ncpt = cfs_cpt_number(pcl->pcl_cptab); > > int i; > > diff --git a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > > index 976c61e..257669b 100644 > > --- a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > > +++ b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > > @@ -151,6 +151,7 @@ cfs_trace_buf_type_t cfs_trace_buf_idx_get(void) > > * for details. > > */ > > int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > > + __acquires(&tcd->tc_lock) > > { > > __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); > > if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) > > @@ -165,6 +166,7 @@ int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > > } > > > > void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > > + __releases(&tcd->tcd_lock) > > { > > __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); > > if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) > > diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c > > index ce96bd2..8577f97 100644 > > --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c > > +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c > > @@ -193,6 +193,7 @@ static spinlock_t *cl_object_attr_guard(struct cl_object *o) > > * cl_object_attr_get(), cl_object_attr_set(). > > */ > > void cl_object_attr_lock(struct cl_object *o) > > + __acquires(cl_object_attr_guard(o)) > > { > > spin_lock(cl_object_attr_guard(o)); > > } > > @@ -202,6 +203,7 @@ EXPORT_SYMBOL(cl_object_attr_lock); > > * Releases data-attributes lock, acquired by cl_object_attr_lock(). > > */ > > void cl_object_attr_unlock(struct cl_object *o) > > + __releases(cl_object_attr_guard(o)) > > { > > spin_unlock(cl_object_attr_guard(o)); > > } > > Same thing here. These ones are easy to replace, but the naming scheme of all functions in cl_object.c is consistent, from my point of view it ease code reading where they are called, for example in lustre/lustre/osc/osc_request.c: before: 1827 if (valid != 0) { 1828 cl_object_attr_lock(obj); 1829 cl_object_attr_set(env, obj, attr, valid); 1830 cl_object_attr_unlock(obj); after: 1827 if (valid != 0) { 1828 spin_lock(cl_object_attr_guard(obj)); 1829 cl_object_attr_set(env, obj, attr, valid); 1830 spin_unlock(cl_object_attr_guard(obj)); But I'm here for learning, and I would be grateful to have your opinion. -- Cheers, Loic ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-27 18:34 ` Loïc Pefferkorn @ 2014-11-28 10:00 ` Dan Carpenter 2014-11-28 15:45 ` [HPDD-discuss] " Patrick Farrell 2014-11-28 22:22 ` Greg KH 1 sibling, 1 reply; 9+ messages in thread From: Dan Carpenter @ 2014-11-28 10:00 UTC (permalink / raw) To: Loïc Pefferkorn Cc: Greg KH, keith.mannthey, devel, andreas.dilger, linux-kernel, oleg.drokin, gdonald, HPDD-discuss, john.hammond On Thu, Nov 27, 2014 at 07:34:10PM +0100, Loïc Pefferkorn wrote: > 1827 if (valid != 0) { > 1828 cl_object_attr_lock(obj); > 1829 cl_object_attr_set(env, obj, attr, valid); > 1830 cl_object_attr_unlock(obj); > > after: > > 1827 if (valid != 0) { > 1828 spin_lock(cl_object_attr_guard(obj)); > 1829 cl_object_attr_set(env, obj, attr, valid); > 1830 spin_unlock(cl_object_attr_guard(obj)); The word "_object" doesn't add any new information to the name. If you remove it then the code is improved. spin_lock(cl_attr_guard(obj)); cl_attr_set(env, obj, attr, valid); spin_unlock(cl_attr_guard(obj)); regards, dan carpenter ^ permalink raw reply [flat|nested] 9+ messages in thread
* RE: [HPDD-discuss] [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-28 10:00 ` Dan Carpenter @ 2014-11-28 15:45 ` Patrick Farrell 2014-11-28 16:28 ` Dan Carpenter 0 siblings, 1 reply; 9+ messages in thread From: Patrick Farrell @ 2014-11-28 15:45 UTC (permalink / raw) To: Dan Carpenter, Loïc Pefferkorn Cc: devel@driverdev.osuosl.org, Greg KH, linux-kernel@vger.kernel.org, gdonald@gmail.com, HPDD-discuss@ml01.01.org Dan, I disagree about the change suggested here. In this particular code, 'object_attr' is distinct from 'attr', as in a 'setattr' call on an inode. 'cl_object' is a distinct thing from an inode/file on disk, and specifying it is the objects attr is helpful in understanding there is not a direct relationship to 'attr' in the general filesystem sense. (cl_object attrs are used in determining actual on disk attributes, but there is not a one-to-one correspondence.) I am willing to be corrected, but that is my first feeling here. - Patrick ________________________________________ From: HPDD-discuss [hpdd-discuss-bounces@lists.01.org] on behalf of Dan Carpenter [dan.carpenter@oracle.com] Sent: Friday, November 28, 2014 4:00 AM To: Loïc Pefferkorn Cc: devel@driverdev.osuosl.org; Greg KH; linux-kernel@vger.kernel.org; gdonald@gmail.com; HPDD-discuss@ml01.01.org Subject: Re: [HPDD-discuss] [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance On Thu, Nov 27, 2014 at 07:34:10PM +0100, Loïc Pefferkorn wrote: > 1827 if (valid != 0) { > 1828 cl_object_attr_lock(obj); > 1829 cl_object_attr_set(env, obj, attr, valid); > 1830 cl_object_attr_unlock(obj); > > after: > > 1827 if (valid != 0) { > 1828 spin_lock(cl_object_attr_guard(obj)); > 1829 cl_object_attr_set(env, obj, attr, valid); > 1830 spin_unlock(cl_object_attr_guard(obj)); The word "_object" doesn't add any new information to the name. If you remove it then the code is improved. spin_lock(cl_attr_guard(obj)); cl_attr_set(env, obj, attr, valid); spin_unlock(cl_attr_guard(obj)); regards, dan carpenter _______________________________________________ HPDD-discuss mailing list HPDD-discuss@lists.01.org https://lists.01.org/mailman/listinfo/hpdd-discuss ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [HPDD-discuss] [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-28 15:45 ` [HPDD-discuss] " Patrick Farrell @ 2014-11-28 16:28 ` Dan Carpenter 0 siblings, 0 replies; 9+ messages in thread From: Dan Carpenter @ 2014-11-28 16:28 UTC (permalink / raw) To: Patrick Farrell Cc: Loïc Pefferkorn, devel@driverdev.osuosl.org, Greg KH, linux-kernel@vger.kernel.org, gdonald@gmail.com, HPDD-discuss@ml01.01.org On Fri, Nov 28, 2014 at 03:45:24PM +0000, Patrick Farrell wrote: > Dan, > > I disagree about the change suggested here. In this particular code, > 'object_attr' is distinct from 'attr', as in a 'setattr' call on an > inode. 'cl_object' is a distinct thing from an inode/file on disk, > and specifying it is the objects attr is helpful in understanding > there is not a direct relationship to 'attr' in the general filesystem > sense. (cl_object attrs are used in determining actual on disk > attributes, but there is not a one-to-one correspondence.) > > I am willing to be corrected, but that is my first feeling here. I haven't looked at it deeply. Loïc was suggesting that we need new locking functions to deal with lustre's unwieldy naming schemes and I think we should just fix the names... We already have a cl_attr struct. Is that different from what we're locking here? I don't think anyone will think this takes an inode argument. regards, dan carpenter ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-27 18:34 ` Loïc Pefferkorn 2014-11-28 10:00 ` Dan Carpenter @ 2014-11-28 22:22 ` Greg KH 2014-11-30 19:54 ` Loïc Pefferkorn 1 sibling, 1 reply; 9+ messages in thread From: Greg KH @ 2014-11-28 22:22 UTC (permalink / raw) To: Loïc Pefferkorn Cc: oleg.drokin, andreas.dilger, gdonald, keith.mannthey, john.hammond, devel, HPDD-discuss, linux-kernel On Thu, Nov 27, 2014 at 07:34:10PM +0100, Loïc Pefferkorn wrote: > Hello Greg, > > After some investigation, I think that removing these wrappers is not going to improve the code readability: > > On Wed, Nov 26, 2014 at 12:54:43PM -0800, Greg KH wrote: > > On Wed, Nov 26, 2014 at 05:15:48PM +0100, Loic Pefferkorn wrote: > > > Add __acquires() and __releases() function annotations, to fix sparse warnings related to lock context imbalance. > > > > > > This fixes the following warnings: > > > > > > drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c:153:5: warning: context imbalance in 'cfs_trace_lock_tcd' - wrong count at exit > > > drivers/staging/lustre/lustre/libcfs/hash.c:128:1: warning: context imbalance in 'cfs_hash_spin_lock' - wrong count at exit > > > drivers/staging/lustre/lustre/libcfs/hash.c:142:9: warning: context imbalance in 'cfs_hash_rw_lock' - wrong count at exit > > > drivers/staging/lustre/lustre/ptlrpc/../../lustre/ldlm/l_lock.c:57:17: warning: context imbalance in 'lock_res_and_lock' - wrong count at exit > > > drivers/staging/lustre/lustre/libcfs/libcfs_lock.c:93:1: warning: context imbalance in 'cfs_percpt_lock' - wrong count at exit > > > > > > Signed-off-by: Loic Pefferkorn <loic@loicp.eu> > > > --- > > > drivers/staging/lustre/lustre/libcfs/hash.c | 4 ++++ > > > drivers/staging/lustre/lustre/libcfs/libcfs_lock.c | 2 ++ > > > drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c | 2 ++ > > > drivers/staging/lustre/lustre/obdclass/cl_object.c | 2 ++ > > > 4 files changed, 10 insertions(+) > > > > > > diff --git a/drivers/staging/lustre/lustre/libcfs/hash.c b/drivers/staging/lustre/lustre/libcfs/hash.c > > > index 32da783..7c6e2a3 100644 > > > --- a/drivers/staging/lustre/lustre/libcfs/hash.c > > > +++ b/drivers/staging/lustre/lustre/libcfs/hash.c > > > @@ -126,18 +126,21 @@ cfs_hash_nl_unlock(union cfs_hash_lock *lock, int exclusive) {} > > > > > > static inline void > > > cfs_hash_spin_lock(union cfs_hash_lock *lock, int exclusive) > > > + __acquires(&lock->spin) > > > { > > > spin_lock(&lock->spin); > > > } > > > > > > static inline void > > > cfs_hash_spin_unlock(union cfs_hash_lock *lock, int exclusive) > > > + __releases(&lock->spin) > > > { > > > spin_unlock(&lock->spin); > > > } > > > > Ugh, how horrid, please just delete these functions and push down the > > spin_lock/unlock calls down into the places these are called. > > cfs_hash_spin_lock() and cfs_hash_spin_unlock() are referenced by function pointers later in the same file: > > 165 /** no bucket lock, one spinlock to protect everything */ > 166 static cfs_hash_lock_ops_t cfs_hash_nbl_lops = { > 167 .hs_lock = cfs_hash_spin_lock, > 168 .hs_unlock = cfs_hash_spin_unlock, > 169 .hs_bkt_lock = cfs_hash_nl_lock, > 170 .hs_bkt_unlock = cfs_hash_nl_unlock, > 171 }; > 172 > 173 /** spin bucket lock, rehash is enabled */ > 174 static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops = { > 175 .hs_lock = cfs_hash_rw_lock, > 176 .hs_unlock = cfs_hash_rw_unlock, > 177 .hs_bkt_lock = cfs_hash_spin_lock, > 178 .hs_bkt_unlock = cfs_hash_spin_unlock, > 179 }; That's even worse than I imagined. Putting sparse markings on these function calls is just papering over nonsense. Please work on unwinding the mess so that you don't need callbacks for locks, that is an abstraction that isn't needed. > > > static inline void > > > cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) > > > + __acquires(&lock->rw) > > > { > > > if (!exclusive) > > > read_lock(&lock->rw); > > > @@ -147,6 +150,7 @@ cfs_hash_rw_lock(union cfs_hash_lock *lock, int exclusive) > > > > > > static inline void > > > cfs_hash_rw_unlock(union cfs_hash_lock *lock, int exclusive) > > > + __releases(&lock->rw) > > > { > > > if (!exclusive) > > > read_unlock(&lock->rw); > > > > > > Same for these. > > Likewise for cfs_hash_rw_lock() and cfs_hash_rw_unlock(): > > 173 /** spin bucket lock, rehash is enabled */ > 174 static cfs_hash_lock_ops_t cfs_hash_bkt_spin_lops = { > 175 .hs_lock = cfs_hash_rw_lock, > 176 .hs_unlock = cfs_hash_rw_unlock, > 177 .hs_bkt_lock = cfs_hash_spin_lock, > 178 .hs_bkt_unlock = cfs_hash_spin_unlock, > 179 }; > 180 > 181 /** rw bucket lock, rehash is enabled */ > 182 static cfs_hash_lock_ops_t cfs_hash_bkt_rw_lops = { > 183 .hs_lock = cfs_hash_rw_lock, > 184 .hs_unlock = cfs_hash_rw_unlock, > 185 .hs_bkt_lock = cfs_hash_rw_lock, > 186 .hs_bkt_unlock = cfs_hash_rw_unlock, > 187 }; Same here, ick ick ick. > > > diff --git a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > > > index 2c199c7..1e529fc 100644 > > > --- a/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > > > +++ b/drivers/staging/lustre/lustre/libcfs/libcfs_lock.c > > > @@ -91,6 +91,7 @@ EXPORT_SYMBOL(cfs_percpt_lock_alloc); > > > */ > > > void > > > cfs_percpt_lock(struct cfs_percpt_lock *pcl, int index) > > > + __acquires(pcl->pcl_locks[index]) > > > { > > > int ncpt = cfs_cpt_number(pcl->pcl_cptab); > > > int i; > > > @@ -125,6 +126,7 @@ EXPORT_SYMBOL(cfs_percpt_lock); > > > /** unlock a CPU partition */ > > > void > > > cfs_percpt_unlock(struct cfs_percpt_lock *pcl, int index) > > > + __releases(pcl->pcl_locks[index]) > > > { > > > int ncpt = cfs_cpt_number(pcl->pcl_cptab); > > > int i; > > > diff --git a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > > > index 976c61e..257669b 100644 > > > --- a/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > > > +++ b/drivers/staging/lustre/lustre/libcfs/linux/linux-tracefile.c > > > @@ -151,6 +151,7 @@ cfs_trace_buf_type_t cfs_trace_buf_idx_get(void) > > > * for details. > > > */ > > > int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > > > + __acquires(&tcd->tc_lock) > > > { > > > __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); > > > if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) > > > @@ -165,6 +166,7 @@ int cfs_trace_lock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > > > } > > > > > > void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking) > > > + __releases(&tcd->tcd_lock) > > > { > > > __LASSERT(tcd->tcd_type < CFS_TCD_TYPE_MAX); > > > if (tcd->tcd_type == CFS_TCD_TYPE_IRQ) > > > diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c > > > index ce96bd2..8577f97 100644 > > > --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c > > > +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c > > > @@ -193,6 +193,7 @@ static spinlock_t *cl_object_attr_guard(struct cl_object *o) > > > * cl_object_attr_get(), cl_object_attr_set(). > > > */ > > > void cl_object_attr_lock(struct cl_object *o) > > > + __acquires(cl_object_attr_guard(o)) > > > { > > > spin_lock(cl_object_attr_guard(o)); > > > } > > > @@ -202,6 +203,7 @@ EXPORT_SYMBOL(cl_object_attr_lock); > > > * Releases data-attributes lock, acquired by cl_object_attr_lock(). > > > */ > > > void cl_object_attr_unlock(struct cl_object *o) > > > + __releases(cl_object_attr_guard(o)) > > > { > > > spin_unlock(cl_object_attr_guard(o)); > > > } > > > > Same thing here. > > These ones are easy to replace, but the naming scheme of all functions in cl_object.c is consistent, > from my point of view it ease code reading where they are called, for example in lustre/lustre/osc/osc_request.c: > > before: > > 1827 if (valid != 0) { > 1828 cl_object_attr_lock(obj); > 1829 cl_object_attr_set(env, obj, attr, valid); > 1830 cl_object_attr_unlock(obj); > > after: > > 1827 if (valid != 0) { > 1828 spin_lock(cl_object_attr_guard(obj)); > 1829 cl_object_attr_set(env, obj, attr, valid); > 1830 spin_unlock(cl_object_attr_guard(obj)); > > > But I'm here for learning, and I would be grateful to have your opinion. Don't hide "implementation of locks" in functions like this, it only causes problems. This code has layers of layers of layers of abstractions due to it wanting to be originally ported to other operating systems and lots of different kernel versions of Linux itself. Unwinding and removing those layers is a good thing to do, don't paper over the nonsense by putting sparse markings on pointless functions. thanks, greg k-h ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance 2014-11-28 22:22 ` Greg KH @ 2014-11-30 19:54 ` Loïc Pefferkorn 0 siblings, 0 replies; 9+ messages in thread From: Loïc Pefferkorn @ 2014-11-30 19:54 UTC (permalink / raw) To: Greg KH Cc: oleg.drokin, andreas.dilger, gdonald, keith.mannthey, john.hammond, devel, HPDD-discuss, linux-kernel On Fri, Nov 28, 2014 at 02:22:07PM -0800, Greg KH wrote: > > That's even worse than I imagined. Putting sparse markings on these > function calls is just papering over nonsense. Please work on unwinding > the mess so that you don't need callbacks for locks, that is an > abstraction that isn't needed. > > Same here, ick ick ick. > > > Don't hide "implementation of locks" in functions like this, it only > causes problems. This code has layers of layers of layers of > abstractions due to it wanting to be originally ported to other > operating systems and lots of different kernel versions of Linux itself. > Unwinding and removing those layers is a good thing to do, don't paper > over the nonsense by putting sparse markings on pointless functions. > > thanks, Hi guys, Thanks for your reply. I'm going to write a v2. -- Cheers, Loïc ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2014-11-30 19:54 UTC | newest] Thread overview: 9+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2014-11-26 16:15 [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance Loic Pefferkorn 2014-11-26 20:54 ` Greg KH 2014-11-27 5:30 ` Loïc Pefferkorn 2014-11-27 18:34 ` Loïc Pefferkorn 2014-11-28 10:00 ` Dan Carpenter 2014-11-28 15:45 ` [HPDD-discuss] " Patrick Farrell 2014-11-28 16:28 ` Dan Carpenter 2014-11-28 22:22 ` Greg KH 2014-11-30 19:54 ` Loïc Pefferkorn
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