cifs: Corrections to lock ordering notes

There were a couple of discrepencies in lock ordering for the locks
that were specified in the lock ordering notes. Did an analysis
of the current codebase (using LLM) and found two pairs whose ordering
in these notes were wrong. It also found one lock that was recently
removed, and a few locks that weren't documented here before.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index f6ebd3fd176d7118eb75948170947b5513c40142..103c92442c2824a65b4a8c6ff4de23e9b4fc7c42 100644 (file)
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1945,6 +1945,8 @@ require use of the stronger protocol */
  */
 
 /****************************************************************************
+ * LOCK ORDERING NOTES:
+ ****************************************************************************
  * Here are all the locks (spinlock, mutex, semaphore) in cifs.ko, arranged according
  * to the locking order. i.e. if two locks are to be held together, the lock that
  * appears higher in this list needs to be taken before the other.
@@ -1973,18 +1975,21 @@ require use of the stronger protocol */
  * =====================================================================================
  * Lock                                Protects                        Initialization fn
  * =====================================================================================
+ * cifs_mount_mutex            mount/unmount operations
  * vol_list_lock
  * vol_info->ctx_lock          vol_info->ctx
  * cifs_sb_info->tlink_tree_lock       cifs_sb_info->tlink_tree        cifs_setup_cifs_sb
  * TCP_Server_Info->           TCP_Server_Info                 cifs_get_tcp_session
  * reconnect_mutex
- * TCP_Server_Info->srv_mutex  TCP_Server_Info                 cifs_get_tcp_session
  * cifs_ses->session_mutex     cifs_ses                        sesInfoAlloc
+ * TCP_Server_Info->srv_mutex  TCP_Server_Info                 cifs_get_tcp_session
+ * cifs_tcp_ses_lock           cifs_tcp_ses_list               sesInfoAlloc
  * cifs_tcon->open_file_lock   cifs_tcon->openFileList         tconInfoAlloc
  *                             cifs_tcon->pending_opens
  * cifs_tcon->stat_lock                cifs_tcon->bytes_read           tconInfoAlloc
  *                             cifs_tcon->bytes_written
- * cifs_tcp_ses_lock           cifs_tcp_ses_list               sesInfoAlloc
+ * cifs_tcon->fscache_lock     cifs_tcon->fscache              tconInfoAlloc
+ * cifs_tcon->sb_list_lock     cifs_tcon->cifs_sb_list         tconInfoAlloc
  * GlobalMid_Lock              GlobalMaxActiveXid              init_cifs
  *                             GlobalCurrentXid
  *                             GlobalTotalActiveXid
@@ -2007,6 +2012,8 @@ require use of the stronger protocol */
  *                             ->chans_in_reconnect
  * cifs_tcon->tc_lock          (anything that is not protected by another lock and can change)
  *                                                             tcon_info_alloc
+ * cifs_swnreg_idr_mutex       cifs_swnreg_idr                 cifs_swn.c
+ *                             (witness service registration, accesses tcon fields under tc_lock)
  * inode->i_rwsem, taken by fs/netfs/locking.c e.g. should be taken before cifsInodeInfo locks
  * cifsInodeInfo->open_file_lock       cifsInodeInfo->openFileList     cifs_alloc_inode
  * cifsInodeInfo->writers_lock cifsInodeInfo->writers          cifsInodeInfo_alloc
@@ -2014,12 +2021,12 @@ require use of the stronger protocol */
  *                             ->can_cache_brlcks
  * cifsInodeInfo->deferred_lock        cifsInodeInfo->deferred_closes  cifsInodeInfo_alloc
  * cached_fids->cfid_list_lock cifs_tcon->cfids->entries       init_cached_dirs
- * cached_fid->fid_lock                (anything that is not protected by another lock and can change)
- *                                                             init_cached_dir
+ * cached_fid->dirents.de_mutex        cached_fid->dirents             alloc_cached_dir
  * cifsFileInfo->fh_mutex      cifsFileInfo                    cifs_new_fileinfo
  * cifsFileInfo->file_info_lock        cifsFileInfo->count             cifs_new_fileinfo
  *                             ->invalidHandle                 initiate_cifs_search
  *                             ->oplock_break_cancelled
+ * smbdirect_mr->mutex         RDMA memory region management   (SMBDirect only)
  * mid_q_entry->mid_lock       mid_q_entry->callback           alloc_mid
  *                                                             smb2_mid_entry_alloc
  *                             (Any fields of mid_q_entry that will need protection)