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  1. 13 Dec, 2021 8 commits
    • NeilBrown's avatar
      NFSD: narrow nfsd_mutex protection in nfsd thread · 9d3792ae
      NeilBrown authored 
      There is nothing happening in the start of nfsd() that requires
protection by the mutex, so don't take it until shutting down the thread
- which does still require protection - but only for nfsd_put().
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      9d3792ae
    • NeilBrown's avatar
      SUNRPC: use sv_lock to protect updates to sv_nrthreads. · 2a36395f
      NeilBrown authored 
      Using sv_lock means we don't need to hold the service mutex over these
updates.

In particular,  svc_exit_thread() no longer requires synchronisation, so
threads can exit asynchronously.

Note that we could use an atomic_t, but as there are many more read
sites than writes, that would add unnecessary noise to the code.
Some reads are already racy, and there is no need for them to not be.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      2a36395f
    • NeilBrown's avatar
      nfsd: make nfsd_stats.th_cnt atomic_t · 9b6c8c9b
      NeilBrown authored 
      This allows us to move the updates for th_cnt out of the mutex.
This is a step towards reducing mutex coverage in nfsd().
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      9b6c8c9b
    • NeilBrown's avatar
      SUNRPC: stop using ->sv_nrthreads as a refcount · ec52361d
      NeilBrown authored 
      The use of sv_nrthreads as a general refcount results in clumsy code, as
is seen by various comments needed to explain the situation.

This patch introduces a 'struct kref' and uses that for reference
counting, leaving sv_nrthreads to be a pure count of threads.  The kref
is managed particularly in svc_get() and svc_put(), and also nfsd_put();

svc_destroy() now takes a pointer to the embedded kref, rather than to
the serv.

nfsd allows the svc_serv to exist with ->sv_nrhtreads being zero.  This
happens when a transport is created before the first thread is started.
To support this, a 'keep_active' flag is introduced which holds a ref on
the svc_serv.  This is set when any listening socket is successfully
added (unless there are running threads), and cleared when the number of
threads is set.  So when the last thread exits, the nfs_serv will be
destroyed.
The use of 'keep_active' replaces previous code which checked if there
were any permanent sockets.

We no longer clear ->rq_server when nfsd() exits.  This was done
to prevent svc_exit_thread() from calling svc_destroy().
Instead we take an extra reference to the svc_serv to prevent
svc_destroy() from being called.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      ec52361d
    • NeilBrown's avatar
      SUNRPC/NFSD: clean up get/put functions. · 8c62d127
      NeilBrown authored 
      svc_destroy() is poorly named - it doesn't necessarily destroy the svc,
it might just reduce the ref count.
nfsd_destroy() is poorly named for the same reason.

This patch:
 - removes the refcount functionality from svc_destroy(), moving it to
   a new svc_put().  Almost all previous callers of svc_destroy() now
   call svc_put().
 - renames nfsd_destroy() to nfsd_put() and improves the code, using
   the new svc_destroy() rather than svc_put()
 - removes a few comments that explain the important for balanced
   get/put calls.  This should be obvious.

The only non-trivial part of this is that svc_destroy() would call
svc_sock_update() on a non-final decrement.  It can no longer do that,
and svc_put() isn't really a good place of it.  This call is now made
from svc_exit_thread() which seems like a good place.  This makes the
call *before* sv_nrthreads is decremented rather than after.  This
is not particularly important as the call just sets a flag which
causes sv_nrthreads set be checked later.  A subsequent patch will
improve the ordering.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      8c62d127
    • NeilBrown's avatar
      SUNRPC: change svc_get() to return the svc. · df5e49c8
      NeilBrown authored 
      It is common for 'get' functions to return the object that was 'got',
and there are a couple of places where users of svc_get() would be a
little simpler if svc_get() did that.

Make it so.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      df5e49c8
    • NeilBrown's avatar
      NFSD: handle errors better in write_ports_addfd() · 89b24336
      NeilBrown authored 
      If write_ports_add() fails, we shouldn't destroy the serv, unless we had
only just created it.  So if there are any permanent sockets already
attached, leave the serv in place.
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      89b24336
    • Chuck Lever's avatar
      NFSD: Fix sparse warning · c2f1c4bd
      Chuck Lever authored 
      /home/cel/src/linux/linux/fs/nfsd/nfs4proc.c:1539:24: warning: incorrect type in assignment (different base types)
/home/cel/src/linux/linux/fs/nfsd/nfs4proc.c:1539:24:    expected restricted __be32 [usertype] status
/home/cel/src/linux/linux/fs/nfsd/nfs4proc.c:1539:24:    got int
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
      c2f1c4bd
  3. 12 Dec, 2021 14 commits
  5. 11 Dec, 2021 18 commits
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