Hi Michał,
Thank you so much for reviewing.
On 11/7/22 5:26 PM, Michał Mirosław wrote:
+
+/*
+ * struct page_region - Page region with bitmap flags
+ * @start: Start of the region
+ * @len: Length of the region
+ * bitmap: Bits sets for the region
+ */
+struct page_region {
+ __u64 start;
+ __u64 len;
+ __u32 bitmap;
+ __u32 __reserved;
"u64 flags"? If an extension is needed it would already require a new
ioctl or something in the `arg` struct.
I feel like the masks must have the same type as this bitmap variable as
the return_mask specifies the flags to be returned in bitmap. All the
masks are of type __u32. This is why I'd kept the bitmap of type _u32 as
well. I've kept them of 32 bit size as currently we are adding support
for 4 flags and there is still room to add 28 more bits in the future.
Do you still think that I should update the masks and bitmap to _u64?
+ * @start: Starting address of the region
+ * @len: Length of the region (All the pages in this length are included)
+ * @vec: Address of page_region struct array for output
+ * @vec_len: Length of the page_region struct array
+ * @max_pages: Optional max return pages (It must be less than vec_len if specified)
I think we discussed that this is not counting the same things as
vec_len, so there should not be a reference between the two. The limit
is whatever fits under both conditions (IOW: n_vecs <= vec_len &&
(!max_pages || n_pages <= max_pages).
In worse case when pages cannot be folded into the page_region, the one
page_region may have information of only one page. This is why I've
compared them. I want to communicate to the user that if max_pages is
used, the vec_len should be of equal or greater size (to cater worse
case which can happen at any time). Otherwise in worse case, the api can
return without finding the max_pages number of pages. I don't know how
should I put this in the comment.
(I only reviewed the API now. The implementation I think could be
simpler, but let's leave that to after the API is agreed on.)
Best Regards
Michał Mirosław
