kernfs: Use a per-fs rwsem to protect per-fs list of kernfs_super_info.
authorImran Khan <imran.f.khan@oracle.com>
Thu, 9 Mar 2023 11:09:31 +0000 (22:09 +1100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 29 Mar 2023 10:23:45 +0000 (12:23 +0200)
commitc9f2dfb7b59e5a6db054f821a6e1a6db8fa57d64
tree05c655fea0c99066e83b7593479ccbc6d9e10389
parent9caf696142252a466fb89e629d0eddcdced027b0
kernfs: Use a per-fs rwsem to protect per-fs list of kernfs_super_info.

Right now per-fs kernfs_rwsem protects list of kernfs_super_info instances
for a kernfs_root. Since kernfs_rwsem is used to synchronize several other
operations across kernfs and since most of these operations don't impact
kernfs_super_info, we can use a separate per-fs rwsem to synchronize access
to list of kernfs_super_info.
This helps in reducing contention around kernfs_rwsem and also allows
operations that change/access list of kernfs_super_info to proceed without
contending for kernfs_rwsem.

Signed-off-by: Imran Khan <imran.f.khan@oracle.com>
Link: https://lore.kernel.org/r/20230309110932.2889010-3-imran.f.khan@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/kernfs/dir.c
fs/kernfs/file.c
fs/kernfs/kernfs-internal.h
fs/kernfs/mount.c