[Stgt-devel] ibmvio is slow

Bastian Blank waldi
Tue Aug 14 21:20:54 CEST 2007

On Tue, Aug 14, 2007 at 08:36:02PM +0200, Bastian Blank wrote:
> There is only lvm between it. This looks like some sort of read-ahead
> for the data, which should not happen for write requests. I tried to dig
> a little bit in the block code but was not able to found the cause.

I found something:

| int write = (data_dir == DMA_TO_DEVICE);

According to ibmvstgt, this is a write to the scsi device, aka data
transfer to this system.

| rq = blk_get_request(shost->uspace_req_q, !write, gfp_mask);

The second parameter should be READ or WRITE, not true/false and it
seems to have the wrong direction.


War is never imperative.
		-- McCoy, "Balance of Terror", stardate 1709.2

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