On Tue, Jan 15 2008 at 19:52 +0200, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > this patch depends on the sg branch of the block tree > > James > > --- > From: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> > Date: Tue, 15 Jan 2008 11:11:46 -0600 > Subject: remove use_sg_chaining > > With the sg table code, every SCSI driver is now either chain capable > or broken, so there's no need to have a check in the host template. > > Also tidy up the code by moving the scatterlist size defines into the > SCSI includes and permit the last entry of the scatterlist pools not > to be a power of two. > --- I have a theoretical problem that BUGed me from the beginning. Could it happen that a memory critical IO, (that is needed to free memory), be collected into an sg-chained large IO, and the allocation of the multiple sg-pool-allocations fail, thous dead locking on out-of-memory? Is there a mechanism in place that will split large IO's into smaller chunks in the event of out-of-memory condition in prep_fn? Is it possible to call blk_rq_map_sg() with less then what is present at request to only map the starting portion? Boaz - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
