[RFC PATCH v1 33/57] random: Remove PAGE_SIZE compile-time constant assumption

[Ryan Roberts]

To prepare for supporting boot-time page size selection, refactor code
to remove assumptions about PAGE_SIZE being compile-time constant. Code
intended to be equivalent when compile-time page size is active.

Update BUILD_BUG_ON()s to test against page size limits.

Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
---

***NOTE***
Any confused maintainers may want to read the cover note here for context:
https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@xxxxxxx/

 drivers/char/random.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 87fe61295ea1f..49d6c4ef16df4 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -466,7 +466,7 @@ static ssize_t get_random_bytes_user(struct iov_iter *iter)
 		if (!iov_iter_count(iter) || copied != sizeof(block))
 			break;
 
-		BUILD_BUG_ON(PAGE_SIZE % sizeof(block) != 0);
+		BUILD_BUG_ON(PAGE_SIZE_MIN % sizeof(block) != 0);
 		if (ret % PAGE_SIZE == 0) {
 			if (signal_pending(current))
 				break;
@@ -1428,7 +1428,7 @@ static ssize_t write_pool_user(struct iov_iter *iter)
 		if (!iov_iter_count(iter) || copied != sizeof(block))
 			break;
 
-		BUILD_BUG_ON(PAGE_SIZE % sizeof(block) != 0);
+		BUILD_BUG_ON(PAGE_SIZE_MIN % sizeof(block) != 0);
 		if (ret % PAGE_SIZE == 0) {
 			if (signal_pending(current))
 				break;
-- 
2.43.0