Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2015-01-21 Thread Loïc Pefferkorn 
On Sat, Jan 17, 2015 at 03:29:01PM -0800, Greg KH wrote:
 On Sat, Dec 13, 2014 at 03:58:46PM +0100, Loïc Pefferkorn wrote:
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


Cheers, Andreas

Hello,

Thanks for your answer. The annotations look like the best thing to do?
   
   Yes, the annotations still make sense.
   
   Cheers, Andreas
  
  Hello guys,
  
  I believe this patch is still relevant, and can be applied against 
  next-20141212.
 
 If so, please resend, as I don't have it in my queue anymore.
 
 thanks,
 
 greg k-h
 

Hi Greg,

Done: https://lkml.org/lkml/2015/1/20/841

-- 
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Loïc
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Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2015-01-17 Thread Greg KH 
On Sat, Dec 13, 2014 at 03:58:46PM +0100, Loïc Pefferkorn wrote:
   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
   
   
   Cheers, Andreas
   
   Hello,
   
   Thanks for your answer. The annotations look like the best thing to do?
  
  Yes, the annotations still make sense.
  
  Cheers, Andreas
 
 Hello guys,
 
 I believe this patch is still relevant, and can be applied against 
 next-20141212.

If so, please resend, as I don't have it in my queue anymore.

thanks,

greg k-h
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Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-12-13 Thread Loïc Pefferkorn 
  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
  
  
  Cheers, Andreas
  
  Hello,
  
  Thanks for your answer. The annotations look like the best thing to do?
 
 Yes, the annotations still make sense.
 
 Cheers, Andreas

Hello guys,

I believe this patch is still relevant, and can be applied against 
next-20141212.

-- 
Cheers,
Loïc

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Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-12-07 Thread Loïc Pefferkorn 
On Tue, Dec 02, 2014 at 02:11:33PM -0700, Andreas Dilger wrote:
 On Nov 28, 2014, at 11:50 AM, Greg KH gre...@linuxfoundation.org wrote:
  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.
  
  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.
 
 Greg,
 in this case these abstractions are not old layering.  This is part of
 scalable hashing code that we use all over Lustre, since it needs to
 handle thousands/millions of clients/connections/files/locks/RPCs
 or whatever in a lot of places.  Having a single interface to define
 and use these hash functions simplifies the code and avoids bugs,
 like list_* functions do everywhere else in the kernel.
 
 Depending on how the hash table is declared, it may have read/write
 locks or normal spinlocks.  The hash table size may be static, or it
 may grow when the buckets get too full (since the numbers of items
 being hashed may differ by many orders of magnitude on different filesystems) 
 so the actual locking functions used depend on how the
 hash table is set up.
 
 I don't think it is possible to unwind the locking of cfs_hash_* code
 since they are accessed via methods depending on the hash.
 
 Cheers, Andreas
 
  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])
  {
intncpt = cfs_cpt_number(pcl-pcl_cptab);
inti;
  @@

Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-12-07 Thread Andreas Dilger 
On Dec 7, 2014, at 4:57 AM, Loïc Pefferkorn l...@loicp.eu wrote:
 
 On Tue, Dec 02, 2014 at 02:11:33PM -0700, Andreas Dilger wrote:
 On Nov 28, 2014, at 11:50 AM, Greg KH gre...@linuxfoundation.org wrote:
 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.
 
 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.
 
 Greg,
 in this case these abstractions are not old layering.  This is part of
 scalable hashing code that we use all over Lustre, since it needs to
 handle thousands/millions of clients/connections/files/locks/RPCs
 or whatever in a lot of places.  Having a single interface to define
 and use these hash functions simplifies the code and avoids bugs,
 like list_* functions do everywhere else in the kernel.
 
 Depending on how the hash table is declared, it may have read/write
 locks or normal spinlocks.  The hash table size may be static, or it
 may grow when the buckets get too full (since the numbers of items
 being hashed may differ by many orders of magnitude on different 
 filesystems) so the actual locking functions used depend on how the
 hash table is set up.
 
 I don't think it is possible to unwind the locking of cfs_hash_* code
 since they are accessed via methods depending on the hash.
 
 Cheers, Andreas
 
 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])
 {
  intncpt = cfs_cpt_number(pcl-pcl_cptab);
  inti;
 @@ -125,6 +126,7 @@ EXPORT_SYMBOL(cfs_percpt_lock);

Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-12-02 Thread Andreas Dilger 
On Nov 28, 2014, at 11:50 AM, Greg KH gre...@linuxfoundation.org wrote:
 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.
 
 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.

Greg,
in this case these abstractions are not old layering.  This is part of
scalable hashing code that we use all over Lustre, since it needs to
handle thousands/millions of clients/connections/files/locks/RPCs
or whatever in a lot of places.  Having a single interface to define
and use these hash functions simplifies the code and avoids bugs,
like list_* functions do everywhere else in the kernel.

Depending on how the hash table is declared, it may have read/write
locks or normal spinlocks.  The hash table size may be static, or it
may grow when the buckets get too full (since the numbers of items
being hashed may differ by many orders of magnitude on different filesystems) 
so the actual locking functions used depend on how the
hash table is set up.

I don't think it is possible to unwind the locking of cfs_hash_* code
since they are accessed via methods depending on the hash.

Cheers, Andreas

 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])
 {
   intncpt = cfs_cpt_number(pcl-pcl_cptab);
   inti;
 @@ -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

Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-11-28 Thread Greg KH 
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 l...@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])
{

Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-11-26 Thread Greg KH 
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 l...@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));
  }

Re: [PATCH] staging: lustre: fix sparse warnings related to lock context imbalance

2014-11-26 Thread Loïc Pefferkorn 
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
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