From: Matthew Wilcox
Sent: 28 February 2022 20:16
On Mon, Feb 28, 2022 at 12:10:24PM -0800, Linus Torvalds wrote:
We can do
typeof(pos) posin the 'for ()' loop, and never use __iter at all.
That means that inside the for-loop, we use a _different_ 'pos' than outside.
Then we can never use -Wshadow ;-( I'd love to be able to turn it on; it catches real bugs.
+#define list_for_each_entry(pos, head, member) \
- for (typeof(pos) pos = list_first_entry(head, typeof(*pos), member); \
!list_entry_is_head(pos, head, member); \ pos = list_next_entry(pos, member))
Actually can't you use 'pos' to temporarily hold the address of 'member'. Something like: for (pos = (void *)head; \ pos ? ((pos = (void *)pos - offsetof(member)), 1) : 0; \ pos = (void *)pos->next) So that 'pos' is NULL if the loop terminates. No pointers outside structures are generated. Probably need to kill list_entry_is_head() - or it just checks for NULL.
David
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