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authorNeil Brown <neilb@suse.de>2008-07-16 02:58:04 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-16 20:24:47 +0400
commitf1282c844e86db5a041afa41335b5f9eea6cec0c (patch)
tree3736285f2f7ce145fb06538d616a9c1165ffc125 /fs/sysfs/mount.c
parentec748fa9ed3fec44aeebbf86ae050b0cc7a978d9 (diff)
downloadlinux-f1282c844e86db5a041afa41335b5f9eea6cec0c.tar.xz
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/mount.c')
-rw-r--r--fs/sysfs/mount.c15
1 files changed, 15 insertions, 0 deletions
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);