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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2019-11-01 21:36:39 -0400 |
|---|---|---|
| committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2019-11-01 22:26:34 -0400 |
| commit | 5a74ac4c4a97bd8b7dba054304d598e2a882fea6 (patch) | |
| tree | cb2bf8f5d805d99450ce514de25bc31729b00c16 /lib/idr.c | |
| parent | 91abab83839aa2eba073e4a63c729832fdb27ea1 (diff) | |
| download | lwn-5a74ac4c4a97bd8b7dba054304d598e2a882fea6.tar.gz lwn-5a74ac4c4a97bd8b7dba054304d598e2a882fea6.zip | |
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.c | 31 |
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. |