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authorMatthew Wilcox (Oracle) <willy@infradead.org>2019-11-02 04:36:39 +0300
committerMatthew Wilcox (Oracle) <willy@infradead.org>2019-11-02 05:26:34 +0300
commit5a74ac4c4a97bd8b7dba054304d598e2a882fea6 (patch)
treecb2bf8f5d805d99450ce514de25bc31729b00c16 /lib/idr.c
parent91abab83839aa2eba073e4a63c729832fdb27ea1 (diff)
downloadlinux-5a74ac4c4a97bd8b7dba054304d598e2a882fea6.tar.xz
idr: Fix idr_get_next_ul race with idr_remove
Commit 5c089fd0c734 ("idr: Fix idr_get_next race with idr_remove") neglected to fix idr_get_next_ul(). As far as I can tell, nobody's actually using this interface under the RCU read lock, but fix it now before anybody decides to use it. Fixes: 5c089fd0c734 ("idr: Fix idr_get_next race with idr_remove") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Diffstat (limited to 'lib/idr.c')
-rw-r--r--lib/idr.c31
1 files changed, 11 insertions, 20 deletions
diff --git a/lib/idr.c b/lib/idr.c
index 66a374892482..c2cf2c52bbde 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -215,7 +215,7 @@ int idr_for_each(const struct idr *idr,
EXPORT_SYMBOL(idr_for_each);
/**
- * idr_get_next() - Find next populated entry.
+ * idr_get_next_ul() - Find next populated entry.
* @idr: IDR handle.
* @nextid: Pointer to an ID.
*
@@ -224,7 +224,7 @@ EXPORT_SYMBOL(idr_for_each);
* to the ID of the found value. To use in a loop, the value pointed to by
* nextid must be incremented by the user.
*/
-void *idr_get_next(struct idr *idr, int *nextid)
+void *idr_get_next_ul(struct idr *idr, unsigned long *nextid)
{
struct radix_tree_iter iter;
void __rcu **slot;
@@ -245,18 +245,14 @@ void *idr_get_next(struct idr *idr, int *nextid)
}
if (!slot)
return NULL;
- id = iter.index + base;
-
- if (WARN_ON_ONCE(id > INT_MAX))
- return NULL;
- *nextid = id;
+ *nextid = iter.index + base;
return entry;
}
-EXPORT_SYMBOL(idr_get_next);
+EXPORT_SYMBOL(idr_get_next_ul);
/**
- * idr_get_next_ul() - Find next populated entry.
+ * idr_get_next() - Find next populated entry.
* @idr: IDR handle.
* @nextid: Pointer to an ID.
*
@@ -265,22 +261,17 @@ EXPORT_SYMBOL(idr_get_next);
* to the ID of the found value. To use in a loop, the value pointed to by
* nextid must be incremented by the user.
*/
-void *idr_get_next_ul(struct idr *idr, unsigned long *nextid)
+void *idr_get_next(struct idr *idr, int *nextid)
{
- struct radix_tree_iter iter;
- void __rcu **slot;
- unsigned long base = idr->idr_base;
unsigned long id = *nextid;
+ void *entry = idr_get_next_ul(idr, &id);
- id = (id < base) ? 0 : id - base;
- slot = radix_tree_iter_find(&idr->idr_rt, &iter, id);
- if (!slot)
+ if (WARN_ON_ONCE(id > INT_MAX))
return NULL;
-
- *nextid = iter.index + base;
- return rcu_dereference_raw(*slot);
+ *nextid = id;
+ return entry;
}
-EXPORT_SYMBOL(idr_get_next_ul);
+EXPORT_SYMBOL(idr_get_next);
/**
* idr_replace() - replace pointer for given ID.