diff options
Diffstat (limited to 'fs/fcntl.c')
| -rw-r--r-- | fs/fcntl.c | 37 |
1 files changed, 24 insertions, 13 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c index bd215cc791d..cc8e4de2fee 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -141,7 +141,7 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes) return ret; } -#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME) +#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) static int setfl(int fd, struct file * filp, unsigned long arg) { @@ -177,21 +177,21 @@ static int setfl(int fd, struct file * filp, unsigned long arg) return error; /* - * We still need a lock here for now to keep multiple FASYNC calls - * from racing with each other. + * ->fasync() is responsible for setting the FASYNC bit. */ - lock_kernel(); - if ((arg ^ filp->f_flags) & FASYNC) { - if (filp->f_op && filp->f_op->fasync) { - error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); - if (error < 0) - goto out; - } + if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op && + filp->f_op->fasync) { + error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); + if (error < 0) + goto out; + if (error > 0) + error = 0; } - + spin_lock(&filp->f_lock); filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); + spin_unlock(&filp->f_lock); + out: - unlock_kernel(); return error; } @@ -516,7 +516,7 @@ static DEFINE_RWLOCK(fasync_lock); static struct kmem_cache *fasync_cache __read_mostly; /* - * fasync_helper() is used by some character device drivers (mainly mice) + * fasync_helper() is used by almost all character device drivers * to set up the fasync queue. It returns negative on error, 0 if it did * no changes and positive if it added/deleted the entry. */ @@ -531,6 +531,12 @@ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fap if (!new) return -ENOMEM; } + + /* + * We need to take f_lock first since it's not an IRQ-safe + * lock. + */ + spin_lock(&filp->f_lock); write_lock_irq(&fasync_lock); for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { if (fa->fa_file == filp) { @@ -555,7 +561,12 @@ int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fap result = 1; } out: + if (on) + filp->f_flags |= FASYNC; + else + filp->f_flags &= ~FASYNC; write_unlock_irq(&fasync_lock); + spin_unlock(&filp->f_lock); return result; } |