On 15/05/2024 17:52, Guenter Roeck wrote:
max_segment_size is 65280; PAGE_SIZE is 65536; BLK_MAX_SEGMENT_SIZE is
65536
WARNING: CPU: 0 PID: 12 at block/blk-settings.c:202
blk_validate_limits+0x2d4/0x364
...
This is with PPC_BOOK3S_64 which selects a default page size of 64k.
Looking at the old code, I think it did what you suggested above,
void blk_queue_max_segment_size(struct request_queue *q, unsigned int
max_size)
{
if (max_size < PAGE_SIZE) {
max_size = PAGE_SIZE;
printk(KERN_INFO "%s: set to minimum %d\n",
__func__, max_size);
}
...
but assuming that the driver requested a lower limit on purpose that
may not be the best solution.
Right, it is relied on that PAGE_SIZE can fit into a segment.
Never mind, though - I updated my test configuration to explicitly
configure the page size to 4k to work around the problem. With that,
please consider this report a note in case someone hits the problem
on a real system (and sorry for the noise).
Other controllers do have a 4K segment limit and are broken on systems
with 16/64K PAGE_SIZE, like:
https://lore.kernel.org/linux-block/20230612203314.17820-1-bvanassche@xxxxxxx/
Thanks,
John
