From fdf9b9650366c575650edcaaede3a68efbb24919 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 9 Dec 2014 15:25:10 +0100 Subject: [PATCH] xen/blkfront: remove redundant flush_op 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 Signed-off-by: Konrad Rzeszutek Wilk --- 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 2e6c10371b24..2236c6f31608 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, -- 2.34.1