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 <[email protected]>
Cc: Chris Mi <[email protected]>
Cc: Cong Wang <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
---
include/linux/idr.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
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)
/*
--
2.42.0
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 <[email protected]>
> Cc: Chris Mi <[email protected]>
> Cc: Cong Wang <[email protected]>
> Signed-off-by: NeilBrown <[email protected]>
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 <[email protected]>:
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!
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