| Message ID | 169810161336.20306.1410058490199370047@noble.neil.brown.name (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | e8ae8ad479e2d037daa33756e5e72850a7bd37a9 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | Fix termination state for idr_for_each_entry_ul() | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Tue, 2023-10-24 at 09:53 +1100, NeilBrown wrote: > The comment for idr_for_each_entry_ul() states > > after normal termination @entry is left with the value NULL > > This is not correct in the case where UINT_MAX has an entry in the idr. > In that case @entry will be non-NULL after termination. > No current code depends on the documentation being correct, but to > save future code we should fix it. > > Also fix idr_for_each_entry_continue_ul(). While this is not documented > as leaving @entry as NULL, the mellanox driver appears to depend on > it doing so. So make that explicit in the documentation as well as in > the code. > > Fixes: e33d2b74d805 ("idr: fix overflow case for idr_for_each_entry_ul()") > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Chris Mi <chrism@mellanox.com> > Cc: Cong Wang <xiyou.wangcong@gmail.com> > Signed-off-by: NeilBrown <neilb@suse.de> Since the affected user is in the netdev tree, I think we can take this patch. But this is also a sort of gray area of the tree... @Matthew are you ok with that? Thanks, Paolo
Hello: This patch was applied to netdev/net.git (main) by David S. Miller <davem@davemloft.net>: On Tue, 24 Oct 2023 09:53:33 +1100 you wrote: > The comment for idr_for_each_entry_ul() states > > after normal termination @entry is left with the value NULL > > This is not correct in the case where UINT_MAX has an entry in the idr. > In that case @entry will be non-NULL after termination. > No current code depends on the documentation being correct, but to > save future code we should fix it. > > [...] Here is the summary with links: - Fix termination state for idr_for_each_entry_ul() https://git.kernel.org/netdev/net/c/e8ae8ad479e2 You are awesome, thank you!
diff --git a/include/linux/idr.h b/include/linux/idr.h index a0dce14090a9..da5f5fa4a3a6 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -200,7 +200,7 @@ static inline void idr_preload_end(void) */ #define idr_for_each_entry_ul(idr, entry, tmp, id) \ for (tmp = 0, id = 0; \ - tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \ + ((entry) = tmp <= id ? idr_get_next_ul(idr, &(id)) : NULL) != NULL; \ tmp = id, ++id) /** @@ -224,10 +224,12 @@ static inline void idr_preload_end(void) * @id: Entry ID. * * Continue to iterate over entries, continuing after the current position. + * After normal termination @entry is left with the value NULL. This + * is convenient for a "not found" value. */ #define idr_for_each_entry_continue_ul(idr, entry, tmp, id) \ for (tmp = id; \ - tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \ + ((entry) = tmp <= id ? idr_get_next_ul(idr, &(id)) : NULL) != NULL; \ tmp = id, ++id) /*
The comment for idr_for_each_entry_ul() states after normal termination @entry is left with the value NULL This is not correct in the case where UINT_MAX has an entry in the idr. In that case @entry will be non-NULL after termination. No current code depends on the documentation being correct, but to save future code we should fix it. Also fix idr_for_each_entry_continue_ul(). While this is not documented as leaving @entry as NULL, the mellanox driver appears to depend on it doing so. So make that explicit in the documentation as well as in the code. Fixes: e33d2b74d805 ("idr: fix overflow case for idr_for_each_entry_ul()") Cc: Matthew Wilcox <willy@infradead.org> Cc: Chris Mi <chrism@mellanox.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de> --- include/linux/idr.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)