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authorNeil Brown <neilb@suse.de>2008-07-16 08:58:04 +1000
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-16 09:24:47 -0700
commitf1282c844e86db5a041afa41335b5f9eea6cec0c (patch)
tree3736285f2f7ce145fb06538d616a9c1165ffc125 /include/linux/sysfs.h
parentec748fa9ed3fec44aeebbf86ae050b0cc7a978d9 (diff)
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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 'include/linux/sysfs.h')
-rw-r--r--include/linux/sysfs.h27
1 files changed, 24 insertions, 3 deletions
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 8ec406a..d8e0230 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -78,6 +78,8 @@ struct sysfs_ops {
ssize_t (*store)(struct kobject *,struct attribute *,const char *, size_t);
};
+struct sysfs_dirent;
+
#ifdef CONFIG_SYSFS
int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
@@ -118,10 +120,13 @@ void sysfs_remove_file_from_group(struct kobject *kobj,
const struct attribute *attr, const char *group);
void sysfs_notify(struct kobject *kobj, char *dir, char *attr);
-
+void sysfs_notify_dirent(struct sysfs_dirent *sd);
+struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
+ const unsigned char *name);
+struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
+void sysfs_put(struct sysfs_dirent *sd);
void sysfs_printk_last_file(void);
-
-extern int __must_check sysfs_init(void);
+int __must_check sysfs_init(void);
#else /* CONFIG_SYSFS */
@@ -227,6 +232,22 @@ static inline void sysfs_remove_file_from_group(struct kobject *kobj,
static inline void sysfs_notify(struct kobject *kobj, char *dir, char *attr)
{
}
+static inline void sysfs_notify_dirent(struct sysfs_dirent *sd)
+{
+}
+static inline
+struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
+ const unsigned char *name)
+{
+ return NULL;
+}
+static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
+{
+ return NULL;
+}
+static inline void sysfs_put(struct sysfs_dirent *sd)
+{
+}
static inline int __must_check sysfs_init(void)
{
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