Re: [BUG] 2.5.23 mpage io vs queue_max_sectors

[Andrew Morton]

William Lee Irwin III wrote:
> 
> This has been haunting me for a while on a 4 cpu Sequent S-quad with
> 4GB of RAM, and a tray of 12 9GB DCHS09X's attached to a QLogicISP1020.
> People keep saying "hands off" ... so here I am passing the buck.
> 
> Kernel BUG at ll_rw_blk.c:1639

This is happening because we have BIO_MAX_SIZE = 64k,
but that particular driver doesn't like requests which are
that big.

This is the issuewhich Adam, Jens and I have been discussing.
Looks like the preferred solution is an add_page_to_bio() API
in the block layer.

But it's not there yet, so in the short-term, please just do

-#define MPAGE_BIO_MAX_SIZE BIO_MAX_SIZE
+#define MPAGE_BIO_MAX_SIZE 16384

in fs/mpage.c

-