Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932546AbaLJRWE (ORCPT ); Wed, 10 Dec 2014 12:22:04 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:33312 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932167AbaLJRWD (ORCPT ); Wed, 10 Dec 2014 12:22:03 -0500 Date: Wed, 10 Dec 2014 12:21:52 -0500 From: Konrad Rzeszutek Wilk To: Boris Ostrovsky Cc: Vitaly Kuznetsov , David Vrabel , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, Andrew Jones Subject: Re: [PATCH v2] xen/blkfront: remove redundant flush_op Message-ID: <20141210172152.GR4268@laptop.dumpdata.com> References: <54860EA4.7090705@oracle.com> <1418135110-7194-1-git-send-email-vkuznets@redhat.com> <5487620E.8060807@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5487620E.8060807@oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 09, 2014 at 03:56:46PM -0500, Boris Ostrovsky wrote: > On 12/09/2014 09:25 AM, Vitaly Kuznetsov wrote: > >flush_op is unambiguously defined by feature_flush: > > REQ_FUA | REQ_FLUSH -> BLKIF_OP_WRITE_BARRIER > > REQ_FLUSH -> BLKIF_OP_FLUSH_DISKCACHE > > 0 -> 0 > >and thus can be removed. This is just a cleanup. > > > >The patch was suggested by Boris Ostrovsky. > > > >Signed-off-by: Vitaly Kuznetsov > > > Reviewed-by: Boris Ostrovsky Thank you. I am testing this and the xen/blkfront: improve protection against issuing unsupported REQ_FUA right now for 3.19 > > > >--- > >Changes from v1: > > Future-proof feature_flush against new flags [Boris Ostrovsky]. > > > >The patch is supposed to be applied after "xen/blkfront: improve protection > >against issuing unsupported REQ_FUA". > >--- > > drivers/block/xen-blkfront.c | 51 +++++++++++++++++++++++++++----------------- > > 1 file changed, 31 insertions(+), 20 deletions(-) > > > >diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > >index 2e6c103..2236c6f 100644 > >--- a/drivers/block/xen-blkfront.c > >+++ b/drivers/block/xen-blkfront.c > >@@ -126,7 +126,6 @@ struct blkfront_info > > unsigned int persistent_gnts_c; > > unsigned long shadow_free; > > unsigned int feature_flush; > >- unsigned int flush_op; > > unsigned int feature_discard:1; > > unsigned int feature_secdiscard:1; > > unsigned int discard_granularity; > >@@ -479,7 +478,19 @@ static int blkif_queue_request(struct request *req) > > * way. (It's also a FLUSH+FUA, since it is > > * guaranteed ordered WRT previous writes.) > > */ > >- ring_req->operation = info->flush_op; > >+ switch (info->feature_flush & > >+ ((REQ_FLUSH|REQ_FUA))) { > >+ case REQ_FLUSH|REQ_FUA: > >+ ring_req->operation = > >+ BLKIF_OP_WRITE_BARRIER; > >+ break; > >+ case REQ_FLUSH: > >+ ring_req->operation = > >+ BLKIF_OP_FLUSH_DISKCACHE; > >+ break; > >+ default: > >+ ring_req->operation = 0; > >+ } > > } > > ring_req->u.rw.nr_segments = nseg; > > } > >@@ -685,20 +696,26 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size, > > return 0; > > } > >+static const char *flush_info(unsigned int feature_flush) > >+{ > >+ switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) { > >+ case REQ_FLUSH|REQ_FUA: > >+ return "barrier: enabled;"; > >+ case REQ_FLUSH: > >+ return "flush diskcache: enabled;"; > >+ default: > >+ return "barrier or flush: disabled;"; > >+ } > >+} > > static void xlvbd_flush(struct blkfront_info *info) > > { > > blk_queue_flush(info->rq, info->feature_flush); > >- printk(KERN_INFO "blkfront: %s: %s: %s %s %s %s %s\n", > >- info->gd->disk_name, > >- info->flush_op == BLKIF_OP_WRITE_BARRIER ? > >- "barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ? > >- "flush diskcache" : "barrier or flush"), > >- info->feature_flush ? "enabled;" : "disabled;", > >- "persistent grants:", > >- info->feature_persistent ? "enabled;" : "disabled;", > >- "indirect descriptors:", > >- info->max_indirect_segments ? "enabled;" : "disabled;"); > >+ pr_info("blkfront: %s: %s %s %s %s %s\n", > >+ info->gd->disk_name, flush_info(info->feature_flush), > >+ "persistent grants:", info->feature_persistent ? > >+ "enabled;" : "disabled;", "indirect descriptors:", > >+ info->max_indirect_segments ? "enabled;" : "disabled;"); > > } > > static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) > >@@ -1190,7 +1207,6 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) > > if (error == -EOPNOTSUPP) > > error = 0; > > info->feature_flush = 0; > >- info->flush_op = 0; > > xlvbd_flush(info); > > } > > /* fall through */ > >@@ -1810,7 +1826,6 @@ static void blkfront_connect(struct blkfront_info *info) > > physical_sector_size = sector_size; > > info->feature_flush = 0; > >- info->flush_op = 0; > > err = xenbus_gather(XBT_NIL, info->xbdev->otherend, > > "feature-barrier", "%d", &barrier, > >@@ -1823,10 +1838,8 @@ static void blkfront_connect(struct blkfront_info *info) > > * > > * If there are barriers, then we use flush. > > */ > >- if (!err && barrier) { > >+ if (!err && barrier) > > info->feature_flush = REQ_FLUSH | REQ_FUA; > >- info->flush_op = BLKIF_OP_WRITE_BARRIER; > >- } > > /* > > * And if there is "feature-flush-cache" use that above > > * barriers. > >@@ -1835,10 +1848,8 @@ static void blkfront_connect(struct blkfront_info *info) > > "feature-flush-cache", "%d", &flush, > > NULL); > >- if (!err && flush) { > >+ if (!err && flush) > > info->feature_flush = REQ_FLUSH; > >- info->flush_op = BLKIF_OP_FLUSH_DISKCACHE; > >- } > > err = xenbus_gather(XBT_NIL, info->xbdev->otherend, > > "feature-discard", "%d", &discard, > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/