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author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-28 05:13:34 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-10-28 05:13:34 +0400 |
commit | 7420a8c0de8d99b201aeeab6fed16ca95ebf55a5 (patch) | |
tree | 0787800f490f98ffd41b958e52ab15732335744e /fs/fcntl.c | |
parent | 12ba8d1e9262ce81a695795410bd9ee5c9407ba1 (diff) | |
parent | 72f98e72551fad573c6cace8e8551ef094f482dd (diff) | |
download | linux-7420a8c0de8d99b201aeeab6fed16ca95ebf55a5.tar.xz |
Merge branch 'flock' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
* 'flock' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
locks: turn lock_flocks into a spinlock
fasync: re-organize fasync entry insertion to allow it under a spinlock
locks/nfsd: allocate file lock outside of spinlock
lockd: fix nlmsvc_notify_blocked locking
lockd: push lock_flocks down
Diffstat (limited to 'fs/fcntl.c')
-rw-r--r-- | fs/fcntl.c | 66 |
1 files changed, 50 insertions, 16 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c index f8cc34f542c3..dcdbc6f5c33b 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -640,7 +640,7 @@ static void fasync_free_rcu(struct rcu_head *head) * match the state "is the filp on a fasync list". * */ -static int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) +int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) { struct fasync_struct *fa, **fp; int result = 0; @@ -666,21 +666,28 @@ static int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) return result; } +struct fasync_struct *fasync_alloc(void) +{ + return kmem_cache_alloc(fasync_cache, GFP_KERNEL); +} + /* - * Add a fasync entry. Return negative on error, positive if - * added, and zero if did nothing but change an existing one. - * - * NOTE! It is very important that the FASYNC flag always - * match the state "is the filp on a fasync list". + * NOTE! This can be used only for unused fasync entries: + * entries that actually got inserted on the fasync list + * need to be released by rcu - see fasync_remove_entry. */ -static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) +void fasync_free(struct fasync_struct *new) { - struct fasync_struct *new, *fa, **fp; - int result = 0; + kmem_cache_free(fasync_cache, new); +} - new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); - if (!new) - return -ENOMEM; +/* + * Insert a new entry into the fasync list. Return the pointer to the + * old one if we didn't use the new one. + */ +struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) +{ + struct fasync_struct *fa, **fp; spin_lock(&filp->f_lock); spin_lock(&fasync_lock); @@ -691,8 +698,6 @@ static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fa spin_lock_irq(&fa->fa_lock); fa->fa_fd = fd; spin_unlock_irq(&fa->fa_lock); - - kmem_cache_free(fasync_cache, new); goto out; } @@ -702,13 +707,42 @@ static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fa new->fa_fd = fd; new->fa_next = *fapp; rcu_assign_pointer(*fapp, new); - result = 1; filp->f_flags |= FASYNC; out: spin_unlock(&fasync_lock); spin_unlock(&filp->f_lock); - return result; + return fa; +} + +/* + * Add a fasync entry. Return negative on error, positive if + * added, and zero if did nothing but change an existing one. + * + * NOTE! It is very important that the FASYNC flag always + * match the state "is the filp on a fasync list". + */ +static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) +{ + struct fasync_struct *new; + + new = fasync_alloc(); + if (!new) + return -ENOMEM; + + /* + * fasync_insert_entry() returns the old (update) entry if + * it existed. + * + * So free the (unused) new entry and return 0 to let the + * caller know that we didn't add any new fasync entries. + */ + if (fasync_insert_entry(fd, filp, fapp, new)) { + fasync_free(new); + return 0; + } + + return 1; } /* |