On Thu, 2012-11-15 at 05:53 -0500, Christoph Hellwig wrote: > On Thu, Nov 08, 2012 at 08:07:17PM +0000, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > This patch adds a new max_write_same_len device attribute for use with > > WRITE_SAME w/ UNMAP=0 backend emulation. > > > > Also, update block limits VPD emulation code in spc_emulate_evpd_b0() to > > set the default MAXIMUM WRITE SAME LENGTH value of zero. > > why do we need an exposed attribute for this? > This is useful for userspace to reduce the allowed maximum from the default 0xFFFF set by IBLOCK. Allowing huge WRITE_SAMEs can very much effect performance (esp. with spinning media), so being able to reduce the max we accept via a userspace tunable is helpful. --nab -- 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
