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authorImran Khan <imran.f.khan@oracle.com>2023-03-09 14:09:32 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-03-29 13:23:45 +0300
commit06fb4736139fde0e1431fe2a5b4912dcb7588d09 (patch)
tree25d2e93df9103be9b2f7a901e0215f1e2a6faef9 /fs/kernfs
parentc9f2dfb7b59e5a6db054f821a6e1a6db8fa57d64 (diff)
downloadlinux-06fb4736139fde0e1431fe2a5b4912dcb7588d09.tar.xz
kernfs: change kernfs_rename_lock into a read-write lock.
kernfs_rename_lock protects a node's ->parent and thus kernfs topology. Thus it can be used in cases that rely on a stable kernfs topology. Change it to a read-write lock for better scalability. Suggested by: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Imran Khan <imran.f.khan@oracle.com> Link: https://lore.kernel.org/r/20230309110932.2889010-4-imran.f.khan@oracle.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 2cdb8516e528..06e27b36216f 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -17,7 +17,7 @@
#include "kernfs-internal.h"
-static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */
+static DEFINE_RWLOCK(kernfs_rename_lock); /* kn->parent and ->name */
/*
* Don't use rename_lock to piggy back on pr_cont_buf. We don't want to
* call pr_cont() while holding rename_lock. Because sometimes pr_cont()
@@ -196,9 +196,9 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
unsigned long flags;
int ret;
- spin_lock_irqsave(&kernfs_rename_lock, flags);
+ read_lock_irqsave(&kernfs_rename_lock, flags);
ret = kernfs_name_locked(kn, buf, buflen);
- spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+ read_unlock_irqrestore(&kernfs_rename_lock, flags);
return ret;
}
@@ -224,9 +224,9 @@ int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
unsigned long flags;
int ret;
- spin_lock_irqsave(&kernfs_rename_lock, flags);
+ read_lock_irqsave(&kernfs_rename_lock, flags);
ret = kernfs_path_from_node_locked(to, from, buf, buflen);
- spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+ read_unlock_irqrestore(&kernfs_rename_lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kernfs_path_from_node);
@@ -294,10 +294,10 @@ struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
struct kernfs_node *parent;
unsigned long flags;
- spin_lock_irqsave(&kernfs_rename_lock, flags);
+ read_lock_irqsave(&kernfs_rename_lock, flags);
parent = kn->parent;
kernfs_get(parent);
- spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+ read_unlock_irqrestore(&kernfs_rename_lock, flags);
return parent;
}
@@ -1731,7 +1731,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
kernfs_get(new_parent);
/* rename_lock protects ->parent and ->name accessors */
- spin_lock_irq(&kernfs_rename_lock);
+ write_lock_irq(&kernfs_rename_lock);
old_parent = kn->parent;
kn->parent = new_parent;
@@ -1742,7 +1742,7 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
kn->name = new_name;
}
- spin_unlock_irq(&kernfs_rename_lock);
+ write_unlock_irq(&kernfs_rename_lock);
kn->hash = kernfs_name_hash(kn->name, kn->ns);
kernfs_link_sibling(kn);