On Thu, 2010-09-16 at 22:46 -0400, James Bottomley wrote: > On Thu, 2010-09-16 at 15:35 -0700, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > > > This patch converts scsi_dispatch_cmd() to only hold struct Scsi_Host->host_lock > > for scsi_cmd_get_serial(), and drops the lock because the call into > > the LLD with host->hostt->queuecommand(). > > > > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> > > --- > > drivers/scsi/scsi.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > > index ad0ed21..06e5b3a 100644 > > --- a/drivers/scsi/scsi.c > > +++ b/drivers/scsi/scsi.c > > @@ -745,6 +745,7 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd) > > * TODO: kill serial or move to blk layer > > */ > > scsi_cmd_get_serial(host, cmd); > > + spin_unlock_irqrestore(host->host_lock, flags); > > So at least from where I stand, my object is to reduce the number of > times we take and release the lock, which this doesn't do. As I said > before: we need to figure out the rest, which likely includes an atomic > for the serial number (which is almost unused). I think the check > against SHOST_DEL is fine unlocked. > Ok, this makes sense if the shost_state == SHOST_DEL check really is OK to be done w/o host_lock held (I really don't know on this one..) So if that is the case, then Tim and Vasu can you guys have a look at dropping the host_lock around serial number usage and post this for review..? I will plan to include the host_lock'less serial number patch into lio-core-2.6.git/drop-host_lock with the rest of the LLD driver conversion patches from this afternoon and respin a new branch for James and Co. to review. Thanks! --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
