aboutsummaryrefslogtreecommitdiffstats
path: root/fs/sysfs
diff options
context:
space:
mode:
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
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')
-rw-r--r--fs/sysfs/dir.c1
-rw-r--r--fs/sysfs/file.c31
-rw-r--r--fs/sysfs/mount.c15
-rw-r--r--fs/sysfs/sysfs.h6
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,
636 636
637 return sd; 637 return sd;
638} 638}
639EXPORT_SYMBOL_GPL(sysfs_get_dirent);
639 640
640static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd, 641static int create_dir(struct kobject *kobj, struct sysfs_dirent *parent_sd,
641 const char *name, struct sysfs_dirent **p_sd) 642 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)
453 return POLLERR|POLLPRI; 453 return POLLERR|POLLPRI;
454} 454}
455 455
456void sysfs_notify_dirent(struct sysfs_dirent *sd)
457{
458 struct sysfs_open_dirent *od;
459
460 spin_lock(&sysfs_open_dirent_lock);
461
462 od = sd->s_attr.open;
463 if (od) {
464 atomic_inc(&od->event);
465 wake_up_interruptible(&od->poll);
466 }
467
468 spin_unlock(&sysfs_open_dirent_lock);
469}
470EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
471
456void sysfs_notify(struct kobject *k, char *dir, char *attr) 472void sysfs_notify(struct kobject *k, char *dir, char *attr)
457{ 473{
458 struct sysfs_dirent *sd = k->sd; 474 struct sysfs_dirent *sd = k->sd;
@@ -463,19 +479,8 @@ void sysfs_notify(struct kobject *k, char *dir, char *attr)
463 sd = sysfs_find_dirent(sd, dir); 479 sd = sysfs_find_dirent(sd, dir);
464 if (sd && attr) 480 if (sd && attr)
465 sd = sysfs_find_dirent(sd, attr); 481 sd = sysfs_find_dirent(sd, attr);
466 if (sd) { 482 if (sd)
467 struct sysfs_open_dirent *od; 483 sysfs_notify_dirent(sd);
468
469 spin_lock(&sysfs_open_dirent_lock);
470
471 od = sd->s_attr.open;
472 if (od) {
473 atomic_inc(&od->event);
474 wake_up_interruptible(&od->poll);
475 }
476
477 spin_unlock(&sysfs_open_dirent_lock);
478 }
479 484
480 mutex_unlock(&sysfs_mutex); 485 mutex_unlock(&sysfs_mutex);
481} 486}
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 @@
16#include <linux/mount.h> 16#include <linux/mount.h>
17#include <linux/pagemap.h> 17#include <linux/pagemap.h>
18#include <linux/init.h> 18#include <linux/init.h>
19#include <linux/module.h>
19 20
20#include "sysfs.h" 21#include "sysfs.h"
21 22
@@ -115,3 +116,17 @@ out_err:
115 sysfs_dir_cachep = NULL; 116 sysfs_dir_cachep = NULL;
116 goto out; 117 goto out;
117} 118}
119
120#undef sysfs_get
121struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
122{
123 return __sysfs_get(sd);
124}
125EXPORT_SYMBOL_GPL(sysfs_get);
126
127#undef sysfs_put
128void sysfs_put(struct sysfs_dirent *sd)
129{
130 __sysfs_put(sd);
131}
132EXPORT_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,
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