Re: Patch "virtio-blk: remove unneeded "likely" statements" has been added to the 5.14-stable tree

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Oct 18, 2021 at 06:22:13AM -0400, Michael S. Tsirkin wrote:
> On Mon, Oct 18, 2021 at 12:02:30PM +0200, gregkh@linuxfoundation.org wrote:
> > 
> > This is a note to let you know that I've just added the patch titled
> > 
> >     virtio-blk: remove unneeded "likely" statements
> > 
> > to the 5.14-stable tree which can be found at:
> >     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> > 
> > The filename of the patch is:
> >      virtio-blk-remove-unneeded-likely-statements.patch
> > and it can be found in the queue-5.14 subdirectory.
> > 
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <stable@vger.kernel.org> know about it.
> > 
> > 
> > >From 6105d1fe6f4c24ce8c13e2e6568b16b76e04983d Mon Sep 17 00:00:00 2001
> > From: Max Gurtovoy <mgurtovoy@nvidia.com>
> > Date: Sun, 5 Sep 2021 11:57:17 +0300
> > Subject: virtio-blk: remove unneeded "likely" statements
> > 
> > From: Max Gurtovoy <mgurtovoy@nvidia.com>
> > 
> > commit 6105d1fe6f4c24ce8c13e2e6568b16b76e04983d upstream.
> > 
> > Usually we use "likely/unlikely" to optimize the fast path. Remove
> > redundant "likely/unlikely" statements in the control path to simplify
> > the code and make it easier to read.
> > 
> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> > Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
> > Link: https://lore.kernel.org/r/20210905085717.7427-1-mgurtovoy@nvidia.com
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > Reviewed-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> It's harmless but doesn't seem appropriate for stable.

Oh, I guess it's been picked because the next patch that
was picked depends on it. OK then, sorry about the noise.

> > ---
> >  drivers/block/virtio_blk.c |    4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > --- a/drivers/block/virtio_blk.c
> > +++ b/drivers/block/virtio_blk.c
> > @@ -765,7 +765,7 @@ static int virtblk_probe(struct virtio_d
> >  		goto out_free_vblk;
> >  
> >  	/* Default queue sizing is to fill the ring. */
> > -	if (likely(!virtblk_queue_depth)) {
> > +	if (!virtblk_queue_depth) {
> >  		queue_depth = vblk->vqs[0].vq->num_free;
> >  		/* ... but without indirect descs, we use 2 descs per req */
> >  		if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
> > @@ -839,7 +839,7 @@ static int virtblk_probe(struct virtio_d
> >  	else
> >  		blk_size = queue_logical_block_size(q);
> >  
> > -	if (unlikely(blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE)) {
> > +	if (blk_size < SECTOR_SIZE || blk_size > PAGE_SIZE) {
> >  		dev_err(&vdev->dev,
> >  			"block size is changed unexpectedly, now is %u\n",
> >  			blk_size);
> > 
> > 
> > Patches currently in stable-queue which might be from mgurtovoy@nvidia.com are
> > 
> > queue-5.14/virtio-blk-remove-unneeded-likely-statements.patch