From ada5c1da8660ecae24b3e75c18ee77d79e099fee Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 30 Nov 2018 10:04:08 +1100 Subject: fs/locks: rename some lists and pointers. struct file lock contains an 'fl_next' pointer which is used to point to the lock that this request is blocked waiting for. So rename it to fl_blocker. The fl_blocked list_head in an active lock is the head of a list of blocked requests. In a request it is a node in that list. These are two distinct uses, so replace with two list_heads with different names. fl_blocked_requests is the head of a list of blocked requests fl_blocked_member is a node in a member of that list. The two different list_heads are never used at the same time, but that will change in a future patch. Note that a tracepoint is changed to report fl_blocker instead of fl_next. Signed-off-by: NeilBrown Reviewed-by: J. Bruce Fields Signed-off-by: Jeff Layton --- fs/locks.c | 59 +++++++++++++++++++++++++++++++---------------------------- 1 file changed, 31 insertions(+), 28 deletions(-) (limited to 'fs/locks.c') diff --git a/fs/locks.c b/fs/locks.c index 2ecb4db8c840..c6df0c8b3d13 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -189,9 +189,9 @@ static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); * This lock protects the blocked_hash. Generally, if you're accessing it, you * want to be holding this lock. * - * In addition, it also protects the fl->fl_block list, and the fl->fl_next - * pointer for file_lock structures that are acting as lock requests (in - * contrast to those that are acting as records of acquired locks). + * In addition, it also protects the fl->fl_blocked_requests list, and the + * fl->fl_blocker pointer for file_lock structures that are acting as lock + * requests (in contrast to those that are acting as records of acquired locks). * * Note that when we acquire this lock in order to change the above fields, * we often hold the flc_lock as well. In certain cases, when reading the fields @@ -293,7 +293,8 @@ static void locks_init_lock_heads(struct file_lock *fl) { INIT_HLIST_NODE(&fl->fl_link); INIT_LIST_HEAD(&fl->fl_list); - INIT_LIST_HEAD(&fl->fl_block); + INIT_LIST_HEAD(&fl->fl_blocked_requests); + INIT_LIST_HEAD(&fl->fl_blocked_member); init_waitqueue_head(&fl->fl_wait); } @@ -332,7 +333,8 @@ void locks_free_lock(struct file_lock *fl) { BUG_ON(waitqueue_active(&fl->fl_wait)); BUG_ON(!list_empty(&fl->fl_list)); - BUG_ON(!list_empty(&fl->fl_block)); + BUG_ON(!list_empty(&fl->fl_blocked_requests)); + BUG_ON(!list_empty(&fl->fl_blocked_member)); BUG_ON(!hlist_unhashed(&fl->fl_link)); locks_release_private(fl); @@ -666,8 +668,8 @@ static void locks_delete_global_blocked(struct file_lock *waiter) static void __locks_delete_block(struct file_lock *waiter) { locks_delete_global_blocked(waiter); - list_del_init(&waiter->fl_block); - waiter->fl_next = NULL; + list_del_init(&waiter->fl_blocked_member); + waiter->fl_blocker = NULL; } static void locks_delete_block(struct file_lock *waiter) @@ -683,16 +685,17 @@ static void locks_delete_block(struct file_lock *waiter) * it seems like the reasonable thing to do. * * Must be called with both the flc_lock and blocked_lock_lock held. The - * fl_block list itself is protected by the blocked_lock_lock, but by ensuring - * that the flc_lock is also held on insertions we can avoid taking the - * blocked_lock_lock in some cases when we see that the fl_block list is empty. + * fl_blocked_requests list itself is protected by the blocked_lock_lock, + * but by ensuring that the flc_lock is also held on insertions we can avoid + * taking the blocked_lock_lock in some cases when we see that the + * fl_blocked_requests list is empty. */ static void __locks_insert_block(struct file_lock *blocker, struct file_lock *waiter) { - BUG_ON(!list_empty(&waiter->fl_block)); - waiter->fl_next = blocker; - list_add_tail(&waiter->fl_block, &blocker->fl_block); + BUG_ON(!list_empty(&waiter->fl_blocked_member)); + waiter->fl_blocker = blocker; + list_add_tail(&waiter->fl_blocked_member, &blocker->fl_blocked_requests); if (IS_POSIX(blocker) && !IS_OFDLCK(blocker)) locks_insert_global_blocked(waiter); } @@ -716,19 +719,19 @@ static void locks_wake_up_blocks(struct file_lock *blocker) /* * Avoid taking global lock if list is empty. This is safe since new * blocked requests are only added to the list under the flc_lock, and - * the flc_lock is always held here. Note that removal from the fl_block - * list does not require the flc_lock, so we must recheck list_empty() - * after acquiring the blocked_lock_lock. + * the flc_lock is always held here. Note that removal from the + * fl_blocked_requests list does not require the flc_lock, so we must + * recheck list_empty() after acquiring the blocked_lock_lock. */ - if (list_empty(&blocker->fl_block)) + if (list_empty(&blocker->fl_blocked_requests)) return; spin_lock(&blocked_lock_lock); - while (!list_empty(&blocker->fl_block)) { + while (!list_empty(&blocker->fl_blocked_requests)) { struct file_lock *waiter; - waiter = list_first_entry(&blocker->fl_block, - struct file_lock, fl_block); + waiter = list_first_entry(&blocker->fl_blocked_requests, + struct file_lock, fl_blocked_member); __locks_delete_block(waiter); if (waiter->fl_lmops && waiter->fl_lmops->lm_notify) waiter->fl_lmops->lm_notify(waiter); @@ -878,7 +881,7 @@ static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) { if (posix_same_owner(fl, block_fl)) - return fl->fl_next; + return fl->fl_blocker; } return NULL; } @@ -1237,7 +1240,7 @@ static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl) error = posix_lock_inode(inode, fl, NULL); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); + error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker); if (!error) continue; @@ -1324,7 +1327,7 @@ int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start, error = posix_lock_inode(inode, &fl, NULL); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl.fl_wait, !fl.fl_next); + error = wait_event_interruptible(fl.fl_wait, !fl.fl_blocker); if (!error) { /* * If we've been sleeping someone might have @@ -1518,7 +1521,7 @@ restart: locks_dispose_list(&dispose); error = wait_event_interruptible_timeout(new_fl->fl_wait, - !new_fl->fl_next, break_time); + !new_fl->fl_blocker, break_time); percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); @@ -1931,7 +1934,7 @@ static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl) error = flock_lock_inode(inode, fl); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); + error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker); if (!error) continue; @@ -2210,7 +2213,7 @@ static int do_lock_file_wait(struct file *filp, unsigned int cmd, error = vfs_lock_file(filp, cmd, fl, NULL); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); + error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker); if (!error) continue; @@ -2581,7 +2584,7 @@ posix_unblock_lock(struct file_lock *waiter) int status = 0; spin_lock(&blocked_lock_lock); - if (waiter->fl_next) + if (waiter->fl_blocker) __locks_delete_block(waiter); else status = -ENOENT; @@ -2707,7 +2710,7 @@ static int locks_show(struct seq_file *f, void *v) lock_get_status(f, fl, iter->li_pos, ""); - list_for_each_entry(bfl, &fl->fl_block, fl_block) + list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member) lock_get_status(f, bfl, iter->li_pos, " ->"); return 0; -- cgit