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authorNeil Brown <neilb@suse.de>2008-07-15 18:58:04 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-16 12:24:47 -0400
commitf1282c844e86db5a041afa41335b5f9eea6cec0c (patch)
tree3736285f2f7ce145fb06538d616a9c1165ffc125 /fs/sysfs/sysfs.h
parentec748fa9ed3fec44aeebbf86ae050b0cc7a978d9 (diff)
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/sysfs/sysfs.h')
-rw-r--r--fs/sysfs/sysfs.h6
1 files changed, 4 insertions, 2 deletions
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,
124 struct sysfs_dirent **p_sd); 124 struct sysfs_dirent **p_sd);
125void sysfs_remove_subdir(struct sysfs_dirent *sd); 125void sysfs_remove_subdir(struct sysfs_dirent *sd);
126 126
127static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) 127static inline struct sysfs_dirent *__sysfs_get(struct sysfs_dirent *sd)
128{ 128{
129 if (sd) { 129 if (sd) {
130 WARN_ON(!atomic_read(&sd->s_count)); 130 WARN_ON(!atomic_read(&sd->s_count));
@@ -132,12 +132,14 @@ static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
132 } 132 }
133 return sd; 133 return sd;
134} 134}
135#define sysfs_get(sd) __sysfs_get(sd)
135 136
136static inline void sysfs_put(struct sysfs_dirent *sd) 137static inline void __sysfs_put(struct sysfs_dirent *sd)
137{ 138{
138 if (sd && atomic_dec_and_test(&sd->s_count)) 139 if (sd && atomic_dec_and_test(&sd->s_count))
139 release_sysfs_dirent(sd); 140 release_sysfs_dirent(sd);
140} 141}
142#define sysfs_put(sd) __sysfs_put(sd)
141 143
142/* 144/*
143 * inode.c 145 * inode.c