Mailinglist Archive: opensuse-kernel (109 mails)

[Jeff Mahoney <jeffm@xxxxxxxx>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 03/07/2010 10:39 AM, Jan Engelhardt wrote:
> On Sunday 2010-03-07 16:35, Jeff Mahoney wrote:
> > On 03/06/2010 02:21 PM, Jan Engelhardt wrote:
> > > Avoid old MUTEX macros and use sema instead, which works
> > > for both default and RT kernels.
> >
> > No.
> >
> > They aren't the "old MUTEX macros", they're used *everywhere* in the
> > regular kernel. If the RT kernel doesn't implement them, that's a bug in
> > the RT kernel, not novfs.
>
> RT has them... but with different names.

RT should be fixed then.

> > There was quite a bit of effort put into replacing semaphore sites with
> > mutexes a while ago. Where a while ago is defined as about 4 years ago.
>
> So, why do people continue adding bad code with init_MUTEX then?

I haven't gone and done a review of it, but it seems like the code that
would have had them added recently falls under the category of un- or
loosely- maintained. The staging drivers have a bunch of init_MUTEX's in
them but those drivers are added without review.

- -Jeff

> > Replacing a mutex with a semaphore when the required behavior is mutual
> > exclusion is, quite simply, a regression.
> >
> > - -Jeff
> >
> >
> > > Signed-off-by: Jan Engelhardt <jengelh@xxxxxxxxxx>
> > >
> > > ---
> > >  fs/novfs/daemon.c  |    9 +++++----
> > >  fs/novfs/inode.c   |    8 +++++---
> > >  fs/novfs/profile.c |    5 +++--
> > >  fs/novfs/scope.c   |    4 ++--
> > >  4 files changed, 15 insertions(+), 11 deletions(-)
> > >
> > > Index: linux-2.6.33-rt/fs/novfs/daemon.c
> > > ===================================================================
> > > --- linux-2.6.33-rt.orig/fs/novfs/daemon.c
> > > +++ linux-2.6.33-rt/fs/novfs/daemon.c
> > > @@ -110,16 +110,17 @@ static atomic_t Daemon_Open_Count = ATOM
> > >  
> > >  static unsigned long Daemon_Command_Timeout = TIMEOUT_VALUE;
> > >  
> > > -static DECLARE_MUTEX(DriveMapLock);
> > > +static struct semaphore DriveMapLock;
> > >  static LIST_HEAD(DriveMapList);
> > >  
> > >  int novfs_max_iosize = PAGE_SIZE;
> > >  
> > > -void novfs_daemon_queue_init()
> > > +void novfs_daemon_queue_init(void)
> > >  {
> > >     INIT_LIST_HEAD(&Daemon_Queue.list);
> > >     spin_lock_init(&Daemon_Queue.lock);
> > > -   init_MUTEX_LOCKED(&Daemon_Queue.semaphore);
> > > +   sema_init(&DriveMapLock, 1);
> > > +   sema_init(&Daemon_Queue.semaphore, 0);
> > >  }
> > >  
> > >  void novfs_daemon_queue_exit(void)
> > > @@ -163,7 +164,7 @@ int Queue_Daemon_Command(void *request,
> > >                     que->status = QUEUE_SENDING;
> > >                     que->flags = 0;
> > >  
> > > -                   init_MUTEX_LOCKED(&que->semaphore);
> > > +                   sema_init(&que->semaphore, 0);
> > >  
> > >                     que->sequence = atomic_inc_return(&Sequence);
> > >  
> > > Index: linux-2.6.33-rt/fs/novfs/inode.c
> > > ===================================================================
> > > --- linux-2.6.33-rt.orig/fs/novfs/inode.c
> > > +++ linux-2.6.33-rt/fs/novfs/inode.c
> > > @@ -298,11 +298,11 @@ static atomic_t novfs_Inode_Number = ATO
> > >  struct dentry *novfs_root = NULL;
> > >  char *novfs_current_mnt = NULL;
> > >  
> > > -DECLARE_MUTEX(InodeList_lock);
> > > +struct semaphore InodeList_lock;
> > >  
> > >  LIST_HEAD(InodeList);
> > >  
> > > -DECLARE_MUTEX(TimeDir_Lock);
> > > +struct semaphore TimeDir_Lock;
> > >  uint64_t lastTime;
> > >  char lastDir[PATH_MAX];
> > >  
> > > @@ -3766,7 +3766,7 @@ struct inode *novfs_get_inode(struct sup
> > >                     id->cntDC = 1;
> > >  
> > >                     INIT_LIST_HEAD(&id->DirCache);
> > > -                   init_MUTEX(&id->DirCacheLock);
> > > +                   sema_init(&id->DirCacheLock, 1);
> > >  
> > >                     id->FileHandle = 0;
> > >                     id->CacheFlag = 0;
> > > @@ -3971,6 +3971,8 @@ int __init init_novfs(void)
> > >  {
> > >     int retCode;
> > >  
> > > +   sema_init(&InodeList_lock, 1);
> > > +   sema_init(&TimeDir_Lock, 1);
> > >     lastDir[0] = 0;
> > >     lastTime = get_nanosecond_time();
> > >  
> > > Index: linux-2.6.33-rt/fs/novfs/profile.c
> > > ===================================================================
> > > --- linux-2.6.33-rt.orig/fs/novfs/profile.c
> > > +++ linux-2.6.33-rt/fs/novfs/profile.c
> > > @@ -60,7 +60,7 @@ static struct proc_dir_entry *dbg_file =
> > >  static struct proc_dir_entry *dentry_file = NULL;
> > >  static struct proc_dir_entry *inode_file = NULL;
> > >  
> > > -static DECLARE_MUTEX(LocalPrint_lock);
> > > +static struct semaphore LocalPrint_lock;
> > >  
> > >  static ssize_t User_proc_write_DbgBuffer(struct file *file, const char 
> > > __user *buf, size_t nbytes, loff_t *ppos)
> > >  {
> > > @@ -622,8 +622,9 @@ uint64_t get_nanosecond_time()
> > >     return (retVal);
> > >  }
> > >  
> > > -void novfs_profile_init()
> > > +void novfs_profile_init(void)
> > >  {
> > > +   sema_init(&LocalPrint_lock, 1);
> > >     if (novfs_procfs_dir)
> > >             dbg_dir = novfs_procfs_dir;
> > >     else
> > > Index: linux-2.6.33-rt/fs/novfs/scope.c
> > > ===================================================================
> > > --- linux-2.6.33-rt.orig/fs/novfs/scope.c
> > > +++ linux-2.6.33-rt/fs/novfs/scope.c
> > > @@ -633,8 +633,8 @@ char *novfs_scope_dget_path(struct dentr
> > >  void novfs_scope_init(void)
> > >  {
> > >     INIT_LIST_HEAD(&Scope_List);
> > > -   init_MUTEX(&Scope_Lock);
> > > -   init_MUTEX_LOCKED(&Scope_Thread_Delay);
> > > +   sema_init(&Scope_Lock, 1);
> > > +   sema_init(&Scope_Thread_Delay, 0);
> > >     kthread_run(Scope_Cleanup_Thread, NULL, "novfs_ST");
> > >  }
> > >  
> >
> >
> > - -- 
> > Jeff Mahoney
> > SUSE Labs
> > -----BEGIN PGP SIGNATURE-----
> > Version: GnuPG v2.0.13 (GNU/Linux)
> > Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/
> >
> > iEYEARECAAYFAkuTx7AACgkQLPWxlyuTD7IZCQCfc6ohZKCKlRvy3nLc4KP318sA
> > /jwAoJ4aJY8Bx4GeiwjXtS8Mw4UmbDQz
> > =7t5A
> > -----END PGP SIGNATURE-----
> > -- 
> > To unsubscribe, e-mail: opensuse-kernel+unsubscribe@xxxxxxxxxxxx
> > For additional commands, e-mail: opensuse-kernel+help@xxxxxxxxxxxx


- -- 
Jeff Mahoney
SUSE Labs
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.13 (GNU/Linux)
Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/

iEYEARECAAYFAkuTypIACgkQLPWxlyuTD7K5iwCfbLYf3h9GlAcnQ6dTOfRhjxIR
Fd4AoIsJYZUWE7FKn1PevLNvmcX3ooCa
=OABO
-----END PGP SIGNATURE-----
-- 
To unsubscribe, e-mail: opensuse-kernel+unsubscribe@xxxxxxxxxxxx
For additional commands, e-mail: opensuse-kernel+help@xxxxxxxxxxxx