[PATCH 1/1] block: Check the queue limit before bio submitting

[Ed Tsai (蔡宗軒)]

On Fri, 2023-11-03 at 01:15 -0700, Christoph Hellwig wrote:
> You need to look into the splitting code to see why the splits are
> suboptimal for your device.  We can't limit the upper bio size as
> we have code relying on it not having arbitrary limits.
> 

The splitting code is working correctly based on the queue limit.
However, since 5.1, full bios are no longer a fixed size and often do
not align with the queue limit. This results in the block layer
splitting some small fragments when submitting consecutive full bios. I
don't think this is specific to a particular device.

While I understand your point about not limiting the bio size, in the
past, the 1MB limit prevented the generation of fragmented bios during
the splitting.