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| author | Alexander Aring <aahringo@redhat.com> | 2020-08-27 22:02:49 +0300 |
|---|---|---|
| committer | David Teigland <teigland@redhat.com> | 2020-08-27 23:59:09 +0300 |
| commit | a47666eb763cc1b8b48bd88185ca56676f40ca89 (patch) | |
| tree | c835fdbfcd8e87d4d5e02a2b3ed0b42397bebc44 /fs/dlm/Kconfig | |
| parent | aa7ab1e20882b04fc3e45da77a9dad5cbbefba99 (diff) | |
| download | linux-a47666eb763cc1b8b48bd88185ca56676f40ca89.tar.xz | |
fs: dlm: make connection hash lockless
There are some problems with the connections_lock. During my
experiements I saw sometimes circular dependencies with sock_lock.
The reason here might be code parts which runs nodeid2con() before
or after sock_lock is acquired.
Another issue are missing locks in for_conn() iteration. Maybe this
works fine because for_conn() is running in a context where
connection_hash cannot be manipulated by others anymore.
However this patch changes the connection_hash to be protected by
sleepable rcu. The hotpath function __find_con() is implemented
lockless as it is only a reader of connection_hash and this hopefully
fixes the circular locking dependencies. The iteration for_conn() will
still call some sleepable functionality, that's why we use sleepable rcu
in this case.
This patch removes the kmemcache functionality as I think I need to
make some free() functionality via call_rcu(). However allocation time
isn't here an issue. The dlm_allow_con will not be protected by a lock
anymore as I think it's enough to just set and flush workqueues
afterwards.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm/Kconfig')
| -rw-r--r-- | fs/dlm/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/dlm/Kconfig b/fs/dlm/Kconfig index f82a4952769d..ee92634196a8 100644 --- a/fs/dlm/Kconfig +++ b/fs/dlm/Kconfig @@ -4,6 +4,7 @@ menuconfig DLM depends on INET depends on SYSFS && CONFIGFS_FS && (IPV6 || IPV6=n) select IP_SCTP + select SRCU help A general purpose distributed lock manager for kernel or userspace applications. |