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idr: Fix idr_get_next_ul race with idr_remove 

Commit 5c089fd0c7 ("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: 5c089fd0c7 ("idr: Fix idr_get_next race with idr_remove")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2019-11-01 21:36:39 -04:00
parent 91abab8383
commit 5a74ac4c4a
1 changed files with 11 additions and 20 deletions
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31
lib/idr.c
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@ -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.