1216761 Commits

Author SHA1 Message Date
Chuck Lever
74ebc69705 NFSD: Add nfsd4_encode_fattr4_space_free()
Refactor the encoder for FATTR4_SPACE_FREE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:22 -04:00
Chuck Lever
83afa09179 NFSD: Add nfsd4_encode_fattr4_space_avail()
Refactor the encoder for FATTR4_SPACE_AVAIL into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:21 -04:00
Chuck Lever
a460cda28e NFSD: Add nfsd4_encode_fattr4_rawdev()
Refactor the encoder for FATTR4_RAWDEV into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:21 -04:00
Chuck Lever
62f31e56d5 NFSD: Add nfsd4_encode_fattr4_owner_group()
Refactor the encoder for FATTR4_OWNER_GROUP into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:21 -04:00
Chuck Lever
fa51a5201b NFSD: Add nfsd4_encode_fattr4_owner()
Refactor the encoder for FATTR4_OWNER into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:20 -04:00
Chuck Lever
9f329fea25 NFSD: Add nfsd4_encode_fattr4_numlinks()
Refactor the encoder for FATTR4_NUMLINKS into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:20 -04:00
Chuck Lever
f4cf504201 NFSD: Add nfsd4_encode_fattr4_mode()
Refactor the encoder for FATTR4_MODE into a helper. In a subsequent
patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:20 -04:00
Chuck Lever
951378dc96 NFSD: Add nfsd4_encode_fattr4_maxwrite()
Refactor the encoder for FATTR4_MAXWRITE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:19 -04:00
Chuck Lever
c17195c397 NFSD: Add nfsd4_encode_fattr4_maxread()
Refactor the encoder for FATTR4_MAXREAD into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:19 -04:00
Chuck Lever
9c1adaccd1 NFSD: Add nfsd4_encode_fattr4_maxname()
Refactor the encoder for FATTR4_MAXNAME into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:19 -04:00
Chuck Lever
b066aa5ca3 NFSD: Add nfsd4_encode_fattr4_maxlink()
Refactor the encoder for FATTR4_MAXLINK into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:18 -04:00
Chuck Lever
7c605dccc5 NFSD: Add nfsd4_encode_fattr4_maxfilesize()
Refactor the encoder for FATTR4_MAXFILESIZE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:18 -04:00
Chuck Lever
a1469a3704 NFSD: Add nfsd4_encode_fattr4_fs_locations()
Refactor the encoder for FATTR4_FS_LOCATIONS into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:18 -04:00
Chuck Lever
b56b752663 NFSD: Add nfsd4_encode_fattr4_files_total()
Refactor the encoder for FATTR4_FILES_TOTAL into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:17 -04:00
Chuck Lever
74361e2b5d NFSD: Add nfsd4_encode_fattr4_files_free()
Refactor the encoder for FATTR4_FILES_FREE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:17 -04:00
Chuck Lever
b0c3a5f8c8 NFSD: Add nfsd4_encode_fattr4_files_avail()
Refactor the encoder for FATTR4_FILES_AVAIL into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:17 -04:00
Chuck Lever
eb7ece81d5 NFSD: Add nfsd4_encode_fattr4_fileid()
Refactor the encoder for FATTR4_FILEID into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:17 -04:00
Chuck Lever
3283bf64ef NFSD: Add nfsd4_encode_fattr4_filehandle()
Refactor the encoder for FATTR4_FILEHANDLE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

We can de-duplicate the other filehandle encoder (in GETFH) using
our new helper.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:16 -04:00
Chuck Lever
07455dc45d NFSD: Add nfsd4_encode_fattr4_acl()
Refactor the encoder for FATTR4_ACL into a helper. In a subsequent
patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:16 -04:00
Chuck Lever
0207ee0818 NFSD: Add nfsd4_encode_nfsace4()
Refactor the ACE encoding helper so that it can eventually be reused
for encoding OPEN results that contain delegation ACEs.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:16 -04:00
Chuck Lever
6515b7d71d NFSD: Add nfsd4_encode_fattr4_aclsupport()
Refactor the encoder for FATTR4_ACLSUPPORT into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:15 -04:00
Chuck Lever
782448e1ec NFSD: Add nfsd4_encode_fattr4_rdattr_error()
Refactor the encoder for FATTR4_RDATTR_ERROR into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:15 -04:00
Chuck Lever
1252b283aa NFSD: Add nfsd4_encode_fattr4_lease_time()
Refactor the encoder for FATTR4_LEASE_TIME into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:15 -04:00
Chuck Lever
b6b6259590 NFSD: Add nfsd4_encode_fattr4_fsid()
Refactor the encoder for FATTR4_FSID into a helper. In a subsequent
patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:14 -04:00
Chuck Lever
d0b28aadfd NFSD: Add nfsd4_encode_fattr4_size()
Refactor the encoder for FATTR4_SIZE into a helper. In a subsequent
patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:14 -04:00
Chuck Lever
263453d9bb NFSD: Add nfsd4_encode_fattr4_change()
Refactor the encoder for FATTR4_CHANGE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

The code is restructured a bit to use the modern xdr_stream flow,
and the encoded cinfo value is made const so that callers of the
encoders can be passed a const cinfo.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:14 -04:00
Chuck Lever
36ed7e6494 NFSD: Add nfsd4_encode_fattr4_fh_expire_type()
Refactor the encoder for FATTR4_FH_EXPIRE_TYPE into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:13 -04:00
Chuck Lever
b06cf37545 NFSD: Add nfsd4_encode_fattr4_type()
Refactor the encoder for FATTR4_TYPE into a helper. In a subsequent
patch, this helper will be called from a bitmask loop.

In addition, restructure the code so that byte-swapping is done on
constant values rather than at run time. Run-time swapping can be
costly on some platforms, and "type" is a frequently-requested
attribute.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:13 -04:00
Chuck Lever
c9090e2733 NFSD: Add nfsd4_encode_fattr4_supported_attrs()
Refactor the encoder for FATTR4_SUPPORTED_ATTRS into a helper. In a
subsequent patch, this helper will be called from a bitmask loop.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:13 -04:00
Chuck Lever
8c4422881f NFSD: Add nfsd4_encode_fattr4__false()
Add an encoding helper that encodes a single boolean "false" value.
Attributes that always return "false" can use this helper.

In a subsequent patch, this helper will be called from a bitmask
loop, so it is given a standardized synopsis.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:12 -04:00
Chuck Lever
c88cb4727a NFSD: Add nfsd4_encode_fattr4__true()
Add an encoding helper that encodes a single boolean "true" value.
Attributes that always return "true" can use this helper.

In a subsequent patch, this helper will be called from a bitmask
loop, so it is given a standardized synopsis.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:12 -04:00
Chuck Lever
83ab8678ad NFSD: Add struct nfsd4_fattr_args
I'm about to split nfsd4_encode_fattr() into a number of smaller
functions. Instead of passing a large number of arguments to each of
the smaller functions, create a struct that can gather the common
argument variables into something with a convenient handle on it.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:12 -04:00
Chuck Lever
c3dcb45bcd NFSD: Clean up nfsd4_encode_setattr()
De-duplicate the encoding of bitmap4 results in
nfsd4_encode_setattr().

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:11 -04:00
Chuck Lever
e64301f51b NFSD: Rename nfsd4_encode_bitmap()
For alignment with the specification, the name of NFSD's encoder
function should match the name of the XDR type.

I've also replaced a few "naked integers" with symbolic constants
that better reflect the usage of these values.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:11 -04:00
Chuck Lever
6cc5829140 NFSD: Add simple u32, u64, and bool encoders
The generic XDR encoders return a length or a negative errno. NFSv4
encoders want to know simply whether the encode ran out of stream
buffer space. The return values for server-side encoding are either
nfs_ok or nfserr_resource.

So far I've found it adds a lot of duplicate code to try to use the
generic XDR encoder utilities when encoding the simple data types in
the NFSv4 operation encoders.

Add a set of NFSv4-specific utilities that handle the basic XDR data
types. These are added in xdr4.h so they might eventually be used by
the callback server and pNFS driver encoders too.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:11 -04:00
Chuck Lever
789ce196a3 SUNRPC: Remove BUG_ON call sites
There is no need to take down the whole system for these assertions.

I'd rather not attempt a heroic save here, as some bug has occurred
that has left the transport data structures in an unknown state.
Just warn and then leak the left-over resources.

Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:10 -04:00
Kinglong Mee
2929ba9b46 nfs: fix the typo of rfc number about xattr in NFSv4
Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:10 -04:00
Chuck Lever
f14122b2c2 tools: ynl: Add source files for nfsd netlink protocol
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:10 -04:00
Lorenzo Bianconi
bd9d6a3efa NFSD: add rpc_status netlink support
Introduce rpc_status netlink support for NFSD in order to dump pending
RPC requests debugging information from userspace.

Closes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=366
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:09 -04:00
Lorenzo Bianconi
13727f85b4 NFSD: introduce netlink stubs
Generate stubs and uAPI for nfsd netlink protocol. For the moment,
the new protocol has one operation: rpc_status.

The generated header and source files are created by running:

  tools/net/ynl/ynl-regen.sh

Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:09 -04:00
Dai Ngo
6c41d9a9bd NFSD: handle GETATTR conflict with write delegation
If the GETATTR request on a file that has write delegation in effect
and the request attributes include the change info and size attribute
then the request is handled as below:

Server sends CB_GETATTR to client to get the latest change info and file
size. If these values are the same as the server's cached values then
the GETATTR proceeds as normal.

If either the change info or file size is different from the server's
cached values, or the file was already marked as modified, then:

    . update time_modify and time_metadata into file's metadata
      with current time

    . encode GETATTR as normal except the file size is encoded with
      the value returned from CB_GETATTR

    . mark the file as modified

If the CB_GETATTR fails for any reasons, the delegation is recalled
and NFS4ERR_DELAY is returned for the GETATTR.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:09 -04:00
Dai Ngo
738401a9bd NFSD: add support for CB_GETATTR callback
Includes:
   . CB_GETATTR proc for nfs4_cb_procedures[]
   . XDR encoding and decoding function for CB_GETATTR request/reply
   . add nfs4_cb_fattr to nfs4_delegation for sending CB_GETATTR
     and store file attributes from client's reply.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:08 -04:00
NeilBrown
15d39883ee SUNRPC: change the back-channel queue to lwq
This removes the need to store and update back-links in the list.
It also remove the need for the _bh version of spin_lock().

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:08 -04:00
NeilBrown
580a25756a SUNRPC: discard sp_lock
sp_lock is now only used to protect sp_all_threads.  This isn't needed
as sp_all_threads is only manipulated through svc_set_num_threads(),
which is already serialized.  Read-acccess only requires rcu_read_lock().
So no more locking is needed.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:08 -04:00
NeilBrown
2e8fc923fe SUNRPC: change sp_nrthreads to atomic_t
Using an atomic_t avoids the need to take a spinlock (which can soon be
removed).

Choosing a thread to kill needs to be careful as we cannot set the "die
now" bit atomically with the test on the count.  Instead we temporarily
increase the count.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:07 -04:00
NeilBrown
9a0e6accc0 SUNRPC: use lwq for sp_sockets - renamed to sp_xprts
lwq avoids using back pointers in lists, and uses less locking.
This introduces a new spinlock, but the other one will be removed in a
future patch.

For svc_clean_up_xprts(), we now dequeue the entire queue, walk it to
remove and process the xprts that need cleaning up, then re-enqueue the
remaining queue.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:07 -04:00
NeilBrown
5b80147e0c SUNRPC: only have one thread waking up at a time
Currently if several items of work become available in quick succession,
that number of threads (if available) will be woken.  By the time some
of them wake up another thread that was already cache-warm might have
come along and completed the work.  Anecdotal evidence suggests as many
as 15% of wakes find nothing to do once they get to the point of
looking.

This patch changes svc_pool_wake_idle_thread() to wake the first thread
on the queue but NOT remove it.  Subsequent calls will wake the same
thread.  Once that thread starts it will dequeue itself and after
dequeueing some work to do, it will wake the next thread if there is more
work ready.  This results in a more orderly increase in the number of
busy threads.

As a bonus, this allows us to reduce locking around the idle queue.
svc_pool_wake_idle_thread() no longer needs to take a lock (beyond
rcu_read_lock()) as it doesn't manipulate the queue, it just looks at
the first item.

The thread itself can avoid locking by using the new
llist_del_first_this() interface.  This will safely remove the thread
itself if it is the head.  If it isn't the head, it will do nothing.
If multiple threads call this concurrently only one will succeed.  The
others will do nothing, so no corruption can result.

If a thread wakes up and finds that it cannot dequeue itself that means
either
- that it wasn't woken because it was the head of the queue.  Maybe the
  freezer woke it.  In that case it can go back to sleep (after trying
  to freeze of course).
- some other thread found there was nothing to do very recently, and
  placed itself on the head of the queue in front of this thread.
  It must check again after placing itself there, so it can be deemed to
  be responsible for any pending work, and this thread can go back to
  sleep until woken.

No code ever tests for busy threads any more.  Only each thread itself
cares if it is busy.  So svc_thread_busy() is no longer needed.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:07 -04:00
NeilBrown
d7926ee8b7 SUNRPC: rename some functions from rqst_ to svc_thread_
Functions which directly manipulate a 'struct rqst', such as
svc_rqst_alloc() or svc_rqst_release_pages(), can reasonably
have "rqst" in there name.
However functions that act on the running thread, such as
XX_should_sleep() or XX_wait_for_work() should seem more
natural with a "svc_thread_" prefix.

So make those changes.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:06 -04:00
NeilBrown
de9e82c355 lib: add light-weight queuing mechanism.
lwq is a FIFO single-linked queue that only requires a spinlock
for dequeueing, which happens in process context.  Enqueueing is atomic
with no spinlock and can happen in any context.

This is particularly useful when work items are queued from BH or IRQ
context, and when they are handled one at a time by dedicated threads.

Avoiding any locking when enqueueing means there is no need to disable
BH or interrupts, which is generally best avoided (particularly when
there are any RT tasks on the machine).

This solution is superior to using "list_head" links because we need
half as many pointers in the data structures, and because list_head
lists would need locking to add items to the queue.

This solution is superior to a bespoke solution as all locking and
container_of casting is integrated, so the interface is simple.

Despite the similar name, this solution meets a distinctly different
need to kfifo.  kfifo provides a fixed sized circular buffer to which
data can be added at one end and removed at the other, and does not
provide any locking.  lwq does not have any size limit and works with
data structures (objects?) rather than data (bytes).

A unit test for basic functionality, which runs at boot time, is included.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: David Gow <davidgow@google.com>
Cc: linux-kernel@vger.kernel.org
Message-Id: <20230911111333.4d1a872330e924a00acb905b@linux-foundation.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:06 -04:00
NeilBrown
8a3e5975ed llist: add llist_del_first_this()
llist_del_first_this() deletes a specific entry from an llist, providing
it is at the head of the list.  Multiple threads can call this
concurrently providing they each offer a different entry.

This can be uses for a set of worker threads which are on the llist when
they are idle.  The head can always be woken, and when it is woken it
can remove itself, and possibly wake the next if there is an excess of
work to do.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
2023-10-16 12:44:06 -04:00