b_dev vs. b_rdev confusion

These are probably dumb questions but I haven't been able to find definitive answers... Is there a set rule on when/where one should use a buffer head's b_dev and when/where one should use b_rdev? I'm been tracing through the kernel source quite a bit and it seems like above ll_rw_blk.c's submit

[PATCH] 2.4.4 breaks VMware

Despite VMware's webpage claiming compatibility issues with 2.4.x kernels I'd been using it without any problem until I upgraded to 2.4.4. I couldn't use their precompiled modules of course but compiling to match the running kernel worked fine previously. This patch replaces a wee bit of code vm