diff options
author | Neil Brown <neilb@suse.de> | 2008-07-16 08:58:04 +1000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-10-16 09:24:47 -0700 |
commit | f1282c844e86db5a041afa41335b5f9eea6cec0c (patch) | |
tree | 3736285f2f7ce145fb06538d616a9c1165ffc125 /fs | |
parent | ec748fa9ed3fec44aeebbf86ae050b0cc7a978d9 (diff) | |
download | linux-f1282c844e86db5a041afa41335b5f9eea6cec0c.tar.bz2 |
sysfs: Support sysfs_notify from atomic context with new sysfs_notify_dirent
Support sysfs_notify from atomic context with new sysfs_notify_dirent
sysfs_notify currently takes sysfs_mutex.
This means that it cannot be called in atomic context.
sysfs_mutex is sometimes held over a malloc (sysfs_rename_dir)
so it can block on low memory.
In md I want to be able to notify on a sysfs attribute from
atomic context, and I don't want to block on low memory because I
could be in the writeout path for freeing memory.
So:
- export the "sysfs_dirent" structure along with sysfs_get, sysfs_put
and sysfs_get_dirent so I can get the sysfs_dirent that I want to
notify on and hold it in an md structure.
- split sysfs_notify_dirent out of sysfs_notify so the sysfs_dirent
can be notified on with no blocking (just a spinlock).
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/sysfs/dir.c | 1 | ||||
-rw-r--r-- | fs/sysfs/file.c | 31 | ||||
-rw-r--r-- | fs/sysfs/mount.c | 15 | ||||
-rw-r--r-- | fs/sysfs/sysfs.h | 6 |
4 files changed, 38 insertions, 15 deletions
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index aedaeba82ae5..53bc7fc31af3 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -636,6 +636,7 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, return sd; } +EXPORT_SYMBOL_GPL(sysfs_get_dirent); static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, const char *name, struct sysfs_dirent **p_sd) diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index ce8339c70a4b..d0d79e6b6d11 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -453,6 +453,22 @@ static unsigned int sysfs_poll(struct file *filp, poll_table *wait) return POLLERR|POLLPRI; } +void sysfs_notify_dirent(struct sysfs_dirent *sd) +{ + struct sysfs_open_dirent *od; + + spin_lock(&sysfs_open_dirent_lock); + + od = sd->s_attr.open; + if (od) { + atomic_inc(&od->event); + wake_up_interruptible(&od->poll); + } + + spin_unlock(&sysfs_open_dirent_lock); +} +EXPORT_SYMBOL_GPL(sysfs_notify_dirent); + void sysfs_notify(struct kobject *k, char *dir, char *attr) { struct sysfs_dirent *sd = k->sd; @@ -463,19 +479,8 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr) sd = sysfs_find_dirent(sd, dir); if (sd && attr) sd = sysfs_find_dirent(sd, attr); - if (sd) { - struct sysfs_open_dirent *od; - - spin_lock(&sysfs_open_dirent_lock); - - od = sd->s_attr.open; - if (od) { - atomic_inc(&od->event); - wake_up_interruptible(&od->poll); - } - - spin_unlock(&sysfs_open_dirent_lock); - } + if (sd) + sysfs_notify_dirent(sd); mutex_unlock(&sysfs_mutex); } diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index 14f0023984d7..ab343e371d64 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -16,6 +16,7 @@ #include <linux/mount.h> #include <linux/pagemap.h> #include <linux/init.h> +#include <linux/module.h> #include "sysfs.h" @@ -115,3 +116,17 @@ out_err: sysfs_dir_cachep = NULL; goto out; } + +#undef sysfs_get +struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) +{ + return __sysfs_get(sd); +} +EXPORT_SYMBOL_GPL(sysfs_get); + +#undef sysfs_put +void sysfs_put(struct sysfs_dirent *sd) +{ + __sysfs_put(sd); +} +EXPORT_SYMBOL_GPL(sysfs_put); diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index a5db496f71c7..93c6d6b27c4d 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -124,7 +124,7 @@ int sysfs_create_subdir(struct kobject *kobj, const char *name, struct sysfs_dirent **p_sd); void sysfs_remove_subdir(struct sysfs_dirent *sd); -static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) +static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd) { if (sd) { WARN_ON(!atomic_read(&sd->s_count)); @@ -132,12 +132,14 @@ static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) } return sd; } +#define sysfs_get(sd) __sysfs_get(sd) -static inline void sysfs_put(struct sysfs_dirent *sd) +static inline void __sysfs_put(struct sysfs_dirent *sd) { if (sd && atomic_dec_and_test(&sd->s_count)) release_sysfs_dirent(sd); } +#define sysfs_put(sd) __sysfs_put(sd) /* * inode.c |