linux-toradex.git/fs/nfs/callback.c, branch v6.11

nfsd: stop setting ->pg_stats for unused stats

2024-03-01T14:12:08+00:00

A lot of places are setting a blank svc_stats in ->pg_stats and never
utilizing these stats.  Remove all of these extra structs as we're not
reporting these stats anywhere.

Signed-off-by: Josef Bacik 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever

SUNRPC: discard sv_refcnt, and svc_get/svc_put

2024-01-07T22:54:33+00:00

sv_refcnt is no longer useful.
lockd and nfs-cb only ever have the svc active when there are a non-zero
number of threads, so sv_refcnt mirrors sv_nrthreads.

nfsd also keeps the svc active between when a socket is added and when
the first thread is started, but we don't really need a refcount for
that.  We can simply not destroy the svc while there are any permanent
sockets attached.

So remove sv_refcnt and the get/put functions.
Instead of a final call to svc_put(), call svc_destroy() instead.
This is changed to also store NULL in the passed-in pointer to make it
easier to avoid use-after-free situations.

Signed-off-by: NeilBrown 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever

SUNRPC: change how svc threads are asked to exit.

2023-10-16T16:44:04+00:00

svc threads are currently stopped using kthread_stop().  This requires
identifying a specific thread.  However we don't care which thread
stops, just as long as one does.

So instead, set a flag in the svc_pool to say that a thread needs to
die, and have each thread check this flag instead of calling
kthread_should_stop().  The first thread to find and clear this flag
then moves towards exiting.

This removes an explicit dependency on sp_all_threads which will make a
future patch simpler.

Signed-off-by: NeilBrown 
Signed-off-by: Chuck Lever

SUNRPC: integrate back-channel processing with svc_recv()

2023-10-16T16:44:03+00:00

Using svc_recv() for (NFSv4.1) back-channel handling means we have just
one mechanism for waking threads.

Also change kthread_freezable_should_stop() in nfs4_callback_svc() to
kthread_should_stop() as used elsewhere.
kthread_freezable_should_stop() effectively adds a try_to_freeze() call,
and svc_recv() already contains that at an appropriate place.

Signed-off-by: NeilBrown 
Cc: Trond Myklebust 
Cc: Anna Schumaker 
Signed-off-by: Chuck Lever

SUNRPC: Clean up bc_svc_process()

2023-10-16T16:44:03+00:00

The test robot complained that, in some build configurations, the
@error variable in bc_svc_process's only caller is set but never
used. This happens because dprintk() is the only consumer of that
value.

 - Remove the dprintk() call sites in favor of the svc_process
   tracepoint
 - The @error variable and the return value of bc_svc_process() are
   now unused, so get rid of them.
 - The @serv parameter is set to rqstp->rq_serv by the only caller,
   and bc_svc_process() then uses it only to set rqstp->rq_serv. It
   can be removed.
 - Rename bc_svc_process() according to the convention that
   globally-visible RPC server functions have names that begin with
   "svc_"; and because it is globally-visible, give it a proper
   kdoc comment.

Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-kbuild-all/202308121314.HA8Rq2XG-lkp@intel.com/
Signed-off-by: Chuck Lever

SUNRPC: Add enum svc_auth_status

2023-08-29T21:45:22+00:00

In addition to the benefits of using an enum rather than a set of
macros, we now have a named type that can improve static type
checking of function return values.

As part of this change, I removed a stale comment from svcauth.h;
the return values from current implementations of the
auth_ops::release method are all zero/negative errno, not the SVC_OK
enum values as the old comment suggested.

Suggested-by: NeilBrown 
Signed-off-by: Chuck Lever

SUNRPC: remove timeout arg from svc_recv()

2023-08-29T21:45:22+00:00

Most svc threads have no interest in a timeout.
nfsd sets it to 1 hour, but this is a wart of no significance.

lockd uses the timeout so that it can call nlmsvc_retry_blocked().
It also sometimes calls svc_wake_up() to ensure this is called.

So change lockd to be consistent and always use svc_wake_up() to trigger
nlmsvc_retry_blocked() - using a timer instead of a timeout to
svc_recv().

And change svc_recv() to not take a timeout arg.

This makes the sp_threads_timedout counter always zero.

Signed-off-by: NeilBrown 
Signed-off-by: Chuck Lever

SUNRPC: change svc_recv() to return void.

2023-08-29T21:45:22+00:00

svc_recv() currently returns a 0 on success or one of two errors:
 - -EAGAIN means no message was successfully received
 - -EINTR means the thread has been told to stop

Previously nfsd would stop as the result of a signal as well as
following kthread_stop().  In that case the difference was useful: EINTR
means stop unconditionally.  EAGAIN means stop if kthread_should_stop(),
continue otherwise.

Now threads only exit when kthread_should_stop() so we don't need the
distinction.

Signed-off-by: NeilBrown 
Signed-off-by: Chuck Lever

SUNRPC: call svc_process() from svc_recv().

2023-08-29T21:45:22+00:00

All callers of svc_recv() go on to call svc_process() on success.
Simplify callers by having svc_recv() do that for them.

This loses one call to validate_process_creds() in nfsd.  That was
debugging code added 14 years ago.  I don't think we need to keep it.

Signed-off-by: NeilBrown 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever

nfsd: don't allow nfsd threads to be signalled.

2023-08-29T21:45:22+00:00

The original implementation of nfsd used signals to stop threads during
shutdown.
In Linux 2.3.46pre5 nfsd gained the ability to shutdown threads
internally it if was asked to run "0" threads.  After this user-space
transitioned to using "rpc.nfsd 0" to stop nfsd and sending signals to
threads was no longer an important part of the API.

In commit 3ebdbe5203a8 ("SUNRPC: discard svo_setup and rename
svc_set_num_threads_sync()") (v5.17-rc1~75^2~41) we finally removed the
use of signals for stopping threads, using kthread_stop() instead.

This patch makes the "obvious" next step and removes the ability to
signal nfsd threads - or any svc threads.  nfsd stops allowing signals
and we don't check for their delivery any more.

This will allow for some simplification in later patches.

A change worth noting is in nfsd4_ssc_setup_dul().  There was previously
a signal_pending() check which would only succeed when the thread was
being shut down.  It should really have tested kthread_should_stop() as
well.  Now it just does the latter, not the former.

Signed-off-by: NeilBrown 
Reviewed-by: Jeff Layton 
Signed-off-by: Chuck Lever