diff options
| author | Neil Brown <neilb@suse.de> | 2009-09-16 03:05:51 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-10-15 02:16:25 +0400 |
| commit | 83db93f4de2d9ae441a491d1dc61c2204f0195de (patch) | |
| tree | 13fb296040c8284cf09f318923aa170212cc245d /fs/sysfs | |
| parent | a6a8357788d6a37f8ad0f7eb46b0a386b613abb9 (diff) | |
| download | linux-83db93f4de2d9ae441a491d1dc61c2204f0195de.tar.xz | |
sysfs: Allow sysfs_notify_dirent to be called from interrupt context.
sysfs_notify_dirent is a simple atomic operation that can be used to
alert user-space that new data can be read from a sysfs attribute.
Unfortunately it cannot currently be called from non-process context
because of its use of spin_lock which is sometimes taken with
interrupts enabled.
So change all lockers of sysfs_open_dirent_lock to disable interrupts,
thus making sysfs_notify_dirent safe to be called from non-process
context (as drivers/md does in md_safemode_timeout).
sysfs_get_open_dirent is (documented as being) only called from
process context, so it uses spin_lock_irq. Other places
use spin_lock_irqsave.
The usage for sysfs_notify_dirent in md_safemode_timeout was
introduced in 2.6.28, so this patch is suitable for that and more
recent kernels.
Reported-by: Joel Andres Granados <jgranado@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/file.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 561a9c050cef..f5ea4680f15f 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -268,7 +268,7 @@ static int sysfs_get_open_dirent(struct sysfs_dirent *sd, struct sysfs_open_dirent *od, *new_od = NULL; retry: - spin_lock(&sysfs_open_dirent_lock); + spin_lock_irq(&sysfs_open_dirent_lock); if (!sd->s_attr.open && new_od) { sd->s_attr.open = new_od; @@ -281,7 +281,7 @@ static int sysfs_get_open_dirent(struct sysfs_dirent *sd, list_add_tail(&buffer->list, &od->buffers); } - spin_unlock(&sysfs_open_dirent_lock); + spin_unlock_irq(&sysfs_open_dirent_lock); if (od) { kfree(new_od); @@ -315,8 +315,9 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd, struct sysfs_buffer *buffer) { struct sysfs_open_dirent *od = sd->s_attr.open; + unsigned long flags; - spin_lock(&sysfs_open_dirent_lock); + spin_lock_irqsave(&sysfs_open_dirent_lock, flags); list_del(&buffer->list); if (atomic_dec_and_test(&od->refcnt)) @@ -324,7 +325,7 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd, else od = NULL; - spin_unlock(&sysfs_open_dirent_lock); + spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); kfree(od); } @@ -456,8 +457,9 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait) void sysfs_notify_dirent(struct sysfs_dirent *sd) { struct sysfs_open_dirent *od; + unsigned long flags; - spin_lock(&sysfs_open_dirent_lock); + spin_lock_irqsave(&sysfs_open_dirent_lock, flags); od = sd->s_attr.open; if (od) { @@ -465,7 +467,7 @@ void sysfs_notify_dirent(struct sysfs_dirent *sd) wake_up_interruptible(&od->poll); } - spin_unlock(&sysfs_open_dirent_lock); + spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags); } EXPORT_SYMBOL_GPL(sysfs_notify_dirent); |