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Diffstat (limited to 'fs/fcntl.c')
-rw-r--r--fs/fcntl.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index bd215cc791da..cc8e4de2fee5 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;
}