From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932841AbbFIIxG (ORCPT ); Tue, 9 Jun 2015 04:53:06 -0400 Received: from smtp.ctxuk.citrix.com ([185.25.65.24]:22395 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752586AbbFIIw5 convert rfc822-to-8bit (ORCPT ); Tue, 9 Jun 2015 04:52:57 -0400 X-IronPort-AV: E=Sophos;i="5.13,579,1427760000"; d="scan'208";a="634923" From: Paul Durrant To: Bob Liu CC: "xen-devel@lists.xen.org" , David Vrabel , "justing@spectralogic.com" , "konrad.wilk@oracle.com" , Roger Pau Monne , "Julien Grall" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH 3/3] xen/block: add multi-page ring support Thread-Topic: [PATCH 3/3] xen/block: add multi-page ring support Thread-Index: AQHQnb/QCWqcLyIzK0WBKNbqLtwK8p2jxYwAgAAiL0A= Date: Tue, 9 Jun 2015 08:52:53 +0000 Message-ID: <9AAE0902D5BC7E449B7C8E4E778ABCD0259410F3@AMSPEX01CL01.citrite.net> References: <1433310003-13089-1-git-send-email-bob.liu@oracle.com> <1433310003-13089-3-git-send-email-bob.liu@oracle.com> <5576A8C0.8000804@oracle.com> In-Reply-To: <5576A8C0.8000804@oracle.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-DLP: AMS1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Bob Liu [mailto:bob.liu@oracle.com] > Sent: 09 June 2015 09:50 > To: Bob Liu > Cc: xen-devel@lists.xen.org; David Vrabel; justing@spectralogic.com; > konrad.wilk@oracle.com; Roger Pau Monne; Paul Durrant; Julien Grall; linux- > kernel@vger.kernel.org > Subject: Re: [PATCH 3/3] xen/block: add multi-page ring support > > > On 06/03/2015 01:40 PM, Bob Liu wrote: > > Extend xen/block to support multi-page ring, so that more requests can be > > issued by using more than one pages as the request ring between blkfront > > and backend. > > As a result, the performance can get improved significantly. > > > > We got some impressive improvements on our highend iscsi storage cluster > > backend. If using 64 pages as the ring, the IOPS increased about 15 times > > for the throughput testing and above doubled for the latency testing. > > > > The reason was the limit on outstanding requests is 32 if use only one-page > > ring, but in our case the iscsi lun was spread across about 100 physical > > drives, 32 was really not enough to keep them busy. > > > > Changes in v2: > > - Rebased to 4.0-rc6. > > - Document on how multi-page ring feature working to linux io/blkif.h. > > > > Changes in v3: > > - Remove changes to linux io/blkif.h and follow the protocol defined > > in io/blkif.h of XEN tree. > > - Rebased to 4.1-rc3 > > > > Changes in v4: > > - Turn to use 'ring-page-order' and 'max-ring-page-order'. > > - A few comments from Roger. > > > > Changes in v5: > > - Clarify with 4k granularity to comment > > - Address more comments from Roger > > > > Signed-off-by: Bob Liu > > Also tested the windows PV driver which also works fine when multi-page > ring feature > was enabled in Linux backend. > http://www.xenproject.org/downloads/windows-pv-drivers.html > Great! Thanks for verifying that :-) Paul > Regards, > -Bob > > > --- > > drivers/block/xen-blkback/blkback.c | 13 ++++ > > drivers/block/xen-blkback/common.h | 2 + > > drivers/block/xen-blkback/xenbus.c | 89 +++++++++++++++++------ > > drivers/block/xen-blkfront.c | 135 +++++++++++++++++++++++++---- > ------ > > 4 files changed, 180 insertions(+), 59 deletions(-) > > > > diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen- > blkback/blkback.c > > index 713fc9f..2126842 100644 > > --- a/drivers/block/xen-blkback/blkback.c > > +++ b/drivers/block/xen-blkback/blkback.c > > @@ -84,6 +84,13 @@ MODULE_PARM_DESC(max_persistent_grants, > > "Maximum number of grants to map persistently"); > > > > /* > > + * Maximum order of pages to be used for the shared ring between front > and > > + * backend, 4KB page granularity is used. > > + */ > > +unsigned int xen_blkif_max_ring_order = > XENBUS_MAX_RING_PAGE_ORDER; > > +module_param_named(max_ring_page_order, > xen_blkif_max_ring_order, int, S_IRUGO); > > +MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages > to be used for the shared ring"); > > +/* > > * The LRU mechanism to clean the lists of persistent grants needs to > > * be executed periodically. The time interval between consecutive > executions > > * of the purge mechanism is set in ms. > > @@ -1438,6 +1445,12 @@ static int __init xen_blkif_init(void) > > if (!xen_domain()) > > return -ENODEV; > > > > + if (xen_blkif_max_ring_order > XENBUS_MAX_RING_PAGE_ORDER) > { > > + pr_info("Invalid max_ring_order (%d), will use default max: > %d.\n", > > + xen_blkif_max_ring_order, > XENBUS_MAX_RING_PAGE_ORDER); > > + xen_blkif_max_ring_order = > XENBUS_MAX_RING_PAGE_ORDER; > > + } > > + > > rc = xen_blkif_interface_init(); > > if (rc) > > goto failed_init; > > diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen- > blkback/common.h > > index 043f13b..8ccc49d 100644 > > --- a/drivers/block/xen-blkback/common.h > > +++ b/drivers/block/xen-blkback/common.h > > @@ -44,6 +44,7 @@ > > #include > > #include > > > > +extern unsigned int xen_blkif_max_ring_order; > > /* > > * This is the maximum number of segments that would be allowed in > indirect > > * requests. This value will also be passed to the frontend. > > @@ -320,6 +321,7 @@ struct xen_blkif { > > struct work_struct free_work; > > /* Thread shutdown wait queue. */ > > wait_queue_head_t shutdown_wq; > > + unsigned int nr_ring_pages; > > }; > > > > struct seg_buf { > > diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen- > blkback/xenbus.c > > index c212d41..deb3f00 100644 > > --- a/drivers/block/xen-blkback/xenbus.c > > +++ b/drivers/block/xen-blkback/xenbus.c > > @@ -25,6 +25,7 @@ > > > > /* Enlarge the array size in order to fully show blkback name. */ > > #define BLKBACK_NAME_LEN (20) > > +#define RINGREF_NAME_LEN (20) > > > > struct backend_info { > > struct xenbus_device *dev; > > @@ -156,8 +157,8 @@ static struct xen_blkif *xen_blkif_alloc(domid_t > domid) > > return blkif; > > } > > > > -static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t gref, > > - unsigned int evtchn) > > +static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref, > > + unsigned int nr_grefs, unsigned int evtchn) > > { > > int err; > > > > @@ -165,7 +166,7 @@ static int xen_blkif_map(struct xen_blkif *blkif, > grant_ref_t gref, > > if (blkif->irq) > > return 0; > > > > - err = xenbus_map_ring_valloc(blkif->be->dev, &gref, 1, > > + err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs, > > &blkif->blk_ring); > > if (err < 0) > > return err; > > @@ -175,21 +176,21 @@ static int xen_blkif_map(struct xen_blkif *blkif, > grant_ref_t gref, > > { > > struct blkif_sring *sring; > > sring = (struct blkif_sring *)blkif->blk_ring; > > - BACK_RING_INIT(&blkif->blk_rings.native, sring, > PAGE_SIZE); > > + BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE > * nr_grefs); > > break; > > } > > case BLKIF_PROTOCOL_X86_32: > > { > > struct blkif_x86_32_sring *sring_x86_32; > > sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring; > > - BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, > PAGE_SIZE); > > + BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, > PAGE_SIZE * nr_grefs); > > break; > > } > > case BLKIF_PROTOCOL_X86_64: > > { > > struct blkif_x86_64_sring *sring_x86_64; > > sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring; > > - BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, > PAGE_SIZE); > > + BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, > PAGE_SIZE * nr_grefs); > > break; > > } > > default: > > @@ -270,7 +271,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) > > i++; > > } > > > > - WARN_ON(i != XEN_BLKIF_REQS_PER_PAGE); > > + WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif- > >nr_ring_pages)); > > > > kmem_cache_free(xen_blkif_cachep, blkif); > > } > > @@ -555,6 +556,11 @@ static int xen_blkbk_probe(struct xenbus_device > *dev, > > if (err) > > goto fail; > > > > + err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page- > order", "%u", > > + xen_blkif_max_ring_order); > > + if (err) > > + pr_warn("%s write out 'max-ring-page-order' failed\n", > __func__); > > + > > err = xenbus_switch_state(dev, XenbusStateInitWait); > > if (err) > > goto fail; > > @@ -818,8 +824,8 @@ again: > > static int connect_ring(struct backend_info *be) > > { > > struct xenbus_device *dev = be->dev; > > - unsigned long ring_ref; > > - unsigned int evtchn; > > + unsigned int ring_ref[XENBUS_MAX_RING_PAGES]; > > + unsigned int evtchn, nr_grefs, ring_page_order; > > unsigned int pers_grants; > > char protocol[64] = ""; > > struct pending_req *req, *n; > > @@ -827,14 +833,57 @@ static int connect_ring(struct backend_info *be) > > > > pr_debug("%s %s\n", __func__, dev->otherend); > > > > - err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", > > - &ring_ref, "event-channel", "%u", &evtchn, NULL); > > - if (err) { > > - xenbus_dev_fatal(dev, err, > > - "reading %s/ring-ref and event-channel", > > + err = xenbus_scanf(XBT_NIL, dev->otherend, "event-channel", > "%u", > > + &evtchn); > > + if (err != 1) { > > + err = -EINVAL; > > + xenbus_dev_fatal(dev, err, "reading %s/event-channel", > > dev->otherend); > > return err; > > } > > + pr_info("event-channel %u\n", evtchn); > > + > > + err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", > "%u", > > + &ring_page_order); > > + if (err != 1) { > > + err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref", > > + "%u", &ring_ref[0]); > > + if (err != 1) { > > + err = -EINVAL; > > + xenbus_dev_fatal(dev, err, "reading %s/ring-ref", > > + dev->otherend); > > + return err; > > + } > > + nr_grefs = 1; > > + pr_info("%s:using single page: ring-ref %d\n", dev- > >otherend, > > + ring_ref[0]); > > + } else { > > + unsigned int i; > > + > > + if (ring_page_order > xen_blkif_max_ring_order) { > > + err = -EINVAL; > > + xenbus_dev_fatal(dev, err, "%s/request %d ring > page order exceed max:%d", > > + dev->otherend, ring_page_order, > > + xen_blkif_max_ring_order); > > + return err; > > + } > > + > > + nr_grefs = 1 << ring_page_order; > > + for (i = 0; i < nr_grefs; i++) { > > + char ring_ref_name[RINGREF_NAME_LEN]; > > + > > + snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring- > ref%u", i); > > + err = xenbus_scanf(XBT_NIL, dev->otherend, > ring_ref_name, > > + "%u", &ring_ref[i]); > > + if (err != 1) { > > + err = -EINVAL; > > + xenbus_dev_fatal(dev, err, "reading %s/%s", > > + dev->otherend, > ring_ref_name); > > + return err; > > + } > > + pr_info("ring-ref%u: %u\n", i, ring_ref[i]); > > + } > > + } > > > > be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT; > > err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", > > @@ -859,12 +908,13 @@ static int connect_ring(struct backend_info *be) > > > > be->blkif->vbd.feature_gnt_persistent = pers_grants; > > be->blkif->vbd.overflow_max_grants = 0; > > + be->blkif->nr_ring_pages = nr_grefs; > > > > - pr_info("ring-ref %ld, event-channel %d, protocol %d (%s) %s\n", > > - ring_ref, evtchn, be->blkif->blk_protocol, protocol, > > + pr_info("ring-pages:%d, event-channel %d, protocol %d (%s) %s\n", > > + nr_grefs, evtchn, be->blkif->blk_protocol, protocol, > > pers_grants ? "persistent grants" : ""); > > > > - for (i = 0; i < XEN_BLKIF_REQS_PER_PAGE; i++) { > > + for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { > > req = kzalloc(sizeof(*req), GFP_KERNEL); > > if (!req) > > goto fail; > > @@ -883,10 +933,9 @@ static int connect_ring(struct backend_info *be) > > } > > > > /* Map the shared frame, irq etc. */ > > - err = xen_blkif_map(be->blkif, ring_ref, evtchn); > > + err = xen_blkif_map(be->blkif, ring_ref, nr_grefs, evtchn); > > if (err) { > > - xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", > > - ring_ref, evtchn); > > + xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", > evtchn); > > return err; > > } > > > > diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c > > index 88e23fd..d3c1a95 100644 > > --- a/drivers/block/xen-blkfront.c > > +++ b/drivers/block/xen-blkfront.c > > @@ -98,7 +98,21 @@ static unsigned int xen_blkif_max_segments = 32; > > module_param_named(max, xen_blkif_max_segments, int, S_IRUGO); > > MODULE_PARM_DESC(max, "Maximum amount of segments in indirect > requests (default is 32)"); > > > > -#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) > > +/* > > + * Maximum order of pages to be used for the shared ring between front > and > > + * backend, 4KB page granularity is used. > > + */ > > +static unsigned int xen_blkif_max_ring_order; > > +module_param_named(max_ring_page_order, > xen_blkif_max_ring_order, int, S_IRUGO); > > +MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages > to be used for the shared ring"); > > + > > +#define BLK_RING_SIZE(info) __CONST_RING_SIZE(blkif, PAGE_SIZE * > (info)->nr_ring_pages) > > +#define BLK_MAX_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE * > XENBUS_MAX_RING_PAGES) > > +/* > > + * ring-ref%i i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19 > > + * characters are enough. Define to 20 to keep consist with backend. > > + */ > > +#define RINGREF_NAME_LEN (20) > > > > /* > > * We have one of these per vbd, whether ide, scsi or 'other'. They > > @@ -114,13 +128,14 @@ struct blkfront_info > > int vdevice; > > blkif_vdev_t handle; > > enum blkif_state connected; > > - int ring_ref; > > + int ring_ref[XENBUS_MAX_RING_PAGES]; > > + unsigned int nr_ring_pages; > > struct blkif_front_ring ring; > > unsigned int evtchn, irq; > > struct request_queue *rq; > > struct work_struct work; > > struct gnttab_free_callback callback; > > - struct blk_shadow shadow[BLK_RING_SIZE]; > > + struct blk_shadow shadow[BLK_MAX_RING_SIZE]; > > struct list_head grants; > > struct list_head indirect_pages; > > unsigned int persistent_gnts_c; > > @@ -139,8 +154,6 @@ static unsigned int nr_minors; > > static unsigned long *minors; > > static DEFINE_SPINLOCK(minor_lock); > > > > -#define MAXIMUM_OUTSTANDING_BLOCK_REQS \ > > - (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE) > > #define GRANT_INVALID_REF 0 > > > > #define PARTS_PER_DISK 16 > > @@ -170,7 +183,7 @@ static int blkfront_setup_indirect(struct > blkfront_info *info); > > static int get_id_from_freelist(struct blkfront_info *info) > > { > > unsigned long free = info->shadow_free; > > - BUG_ON(free >= BLK_RING_SIZE); > > + BUG_ON(free >= BLK_RING_SIZE(info)); > > info->shadow_free = info->shadow[free].req.u.rw.id; > > info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */ > > return free; > > @@ -983,7 +996,7 @@ static void blkif_free(struct blkfront_info *info, int > suspend) > > } > > } > > > > - for (i = 0; i < BLK_RING_SIZE; i++) { > > + for (i = 0; i < BLK_RING_SIZE(info); i++) { > > /* > > * Clear persistent grants present in requests already > > * on the shared ring > > @@ -1033,12 +1046,15 @@ free_shadow: > > flush_work(&info->work); > > > > /* Free resources associated with old device channel. */ > > - if (info->ring_ref != GRANT_INVALID_REF) { > > - gnttab_end_foreign_access(info->ring_ref, 0, > > - (unsigned long)info->ring.sring); > > - info->ring_ref = GRANT_INVALID_REF; > > - info->ring.sring = NULL; > > + for (i = 0; i < info->nr_ring_pages; i++) { > > + if (info->ring_ref[i] != GRANT_INVALID_REF) { > > + gnttab_end_foreign_access(info->ring_ref[i], 0, 0); > > + info->ring_ref[i] = GRANT_INVALID_REF; > > + } > > } > > + free_pages((unsigned long)info->ring.sring, get_order(info- > >nr_ring_pages * PAGE_SIZE)); > > + info->ring.sring = NULL; > > + > > if (info->irq) > > unbind_from_irqhandler(info->irq, info); > > info->evtchn = info->irq = 0; > > @@ -1157,7 +1173,7 @@ static irqreturn_t blkif_interrupt(int irq, void > *dev_id) > > * never have given to it (we stamp it up to BLK_RING_SIZE - > > * look in get_id_from_freelist. > > */ > > - if (id >= BLK_RING_SIZE) { > > + if (id >= BLK_RING_SIZE(info)) { > > WARN(1, "%s: response to %s has incorrect id > (%ld)\n", > > info->gd->disk_name, op_name(bret->operation), > id); > > /* We can't safely get the 'struct request' as > > @@ -1245,26 +1261,30 @@ static int setup_blkring(struct xenbus_device > *dev, > > struct blkfront_info *info) > > { > > struct blkif_sring *sring; > > - grant_ref_t gref; > > - int err; > > + int err, i; > > + unsigned long ring_size = info->nr_ring_pages * PAGE_SIZE; > > + grant_ref_t gref[XENBUS_MAX_RING_PAGES]; > > > > - info->ring_ref = GRANT_INVALID_REF; > > + for (i = 0; i < info->nr_ring_pages; i++) > > + info->ring_ref[i] = GRANT_INVALID_REF; > > > > - sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | > __GFP_HIGH); > > + sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | > __GFP_HIGH, > > + get_order(ring_size)); > > if (!sring) { > > xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring"); > > return -ENOMEM; > > } > > SHARED_RING_INIT(sring); > > - FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE); > > + FRONT_RING_INIT(&info->ring, sring, ring_size); > > > > - err = xenbus_grant_ring(dev, info->ring.sring, 1, &gref); > > + err = xenbus_grant_ring(dev, info->ring.sring, info->nr_ring_pages, > gref); > > if (err < 0) { > > - free_page((unsigned long)sring); > > + free_pages((unsigned long)sring, get_order(ring_size)); > > info->ring.sring = NULL; > > goto fail; > > } > > - info->ring_ref = gref; > > + for (i = 0; i < info->nr_ring_pages; i++) > > + info->ring_ref[i] = gref[i]; > > > > err = xenbus_alloc_evtchn(dev, &info->evtchn); > > if (err) > > @@ -1292,7 +1312,18 @@ static int talk_to_blkback(struct xenbus_device > *dev, > > { > > const char *message = NULL; > > struct xenbus_transaction xbt; > > - int err; > > + int err, i; > > + unsigned int max_page_order = 0; > > + unsigned int ring_page_order = 0; > > + > > + err = xenbus_scanf(XBT_NIL, info->xbdev->otherend, > > + "max-ring-page-order", "%u", &max_page_order); > > + if (err != 1) > > + info->nr_ring_pages = 1; > > + else { > > + ring_page_order = min(xen_blkif_max_ring_order, > max_page_order); > > + info->nr_ring_pages = 1 << ring_page_order; > > + } > > > > /* Create shared ring, alloc event channel. */ > > err = setup_blkring(dev, info); > > @@ -1306,11 +1337,32 @@ again: > > goto destroy_blkring; > > } > > > > - err = xenbus_printf(xbt, dev->nodename, > > - "ring-ref", "%u", info->ring_ref); > > - if (err) { > > - message = "writing ring-ref"; > > - goto abort_transaction; > > + if (info->nr_ring_pages == 1) { > > + err = xenbus_printf(xbt, dev->nodename, > > + "ring-ref", "%u", info->ring_ref[0]); > > + if (err) { > > + message = "writing ring-ref"; > > + goto abort_transaction; > > + } > > + } else { > > + err = xenbus_printf(xbt, dev->nodename, > > + "ring-page-order", "%u", ring_page_order); > > + if (err) { > > + message = "writing ring-page-order"; > > + goto abort_transaction; > > + } > > + > > + for (i = 0; i < info->nr_ring_pages; i++) { > > + char ring_ref_name[RINGREF_NAME_LEN]; > > + > > + snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring- > ref%u", i); > > + err = xenbus_printf(xbt, dev->nodename, > ring_ref_name, > > + "%u", info->ring_ref[i]); > > + if (err) { > > + message = "writing ring-ref"; > > + goto abort_transaction; > > + } > > + } > > } > > err = xenbus_printf(xbt, dev->nodename, > > "event-channel", "%u", info->evtchn); > > @@ -1338,6 +1390,9 @@ again: > > goto destroy_blkring; > > } > > > > + for (i = 0; i < BLK_RING_SIZE(info); i++) > > + info->shadow[i].req.u.rw.id = i+1; > > + info->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff; > > xenbus_switch_state(dev, XenbusStateInitialised); > > > > return 0; > > @@ -1361,7 +1416,7 @@ again: > > static int blkfront_probe(struct xenbus_device *dev, > > const struct xenbus_device_id *id) > > { > > - int err, vdevice, i; > > + int err, vdevice; > > struct blkfront_info *info; > > > > /* FIXME: Use dynamic device id if this is not set. */ > > @@ -1422,10 +1477,6 @@ static int blkfront_probe(struct xenbus_device > *dev, > > info->connected = BLKIF_STATE_DISCONNECTED; > > INIT_WORK(&info->work, blkif_restart_queue); > > > > - for (i = 0; i < BLK_RING_SIZE; i++) > > - info->shadow[i].req.u.rw.id = i+1; > > - info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; > > - > > /* Front end dir is a number, which is used as the id. */ > > info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, > 0); > > dev_set_drvdata(&dev->dev, info); > > @@ -1469,10 +1520,10 @@ static int blkif_recover(struct blkfront_info > *info) > > > > /* Stage 2: Set up free list. */ > > memset(&info->shadow, 0, sizeof(info->shadow)); > > - for (i = 0; i < BLK_RING_SIZE; i++) > > + for (i = 0; i < BLK_RING_SIZE(info); i++) > > info->shadow[i].req.u.rw.id = i+1; > > info->shadow_free = info->ring.req_prod_pvt; > > - info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff; > > + info->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff; > > > > rc = blkfront_setup_indirect(info); > > if (rc) { > > @@ -1484,7 +1535,7 @@ static int blkif_recover(struct blkfront_info *info) > > blk_queue_max_segments(info->rq, segs); > > bio_list_init(&bio_list); > > INIT_LIST_HEAD(&requests); > > - for (i = 0; i < BLK_RING_SIZE; i++) { > > + for (i = 0; i < BLK_RING_SIZE(info); i++) { > > /* Not in use? */ > > if (!copy[i].request) > > continue; > > @@ -1690,7 +1741,7 @@ static int blkfront_setup_indirect(struct > blkfront_info *info) > > segs = info->max_indirect_segments; > > } > > > > - err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * > BLK_RING_SIZE); > > + err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * > BLK_RING_SIZE(info)); > > if (err) > > goto out_of_memory; > > > > @@ -1700,7 +1751,7 @@ static int blkfront_setup_indirect(struct > blkfront_info *info) > > * grants, we need to allocate a set of pages that can be > > * used for mapping indirect grefs > > */ > > - int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE; > > + int num = INDIRECT_GREFS(segs) * BLK_RING_SIZE(info); > > > > BUG_ON(!list_empty(&info->indirect_pages)); > > for (i = 0; i < num; i++) { > > @@ -1711,7 +1762,7 @@ static int blkfront_setup_indirect(struct > blkfront_info *info) > > } > > } > > > > - for (i = 0; i < BLK_RING_SIZE; i++) { > > + for (i = 0; i < BLK_RING_SIZE(info); i++) { > > info->shadow[i].grants_used = kzalloc( > > sizeof(info->shadow[i].grants_used[0]) * segs, > > GFP_NOIO); > > @@ -1733,7 +1784,7 @@ static int blkfront_setup_indirect(struct > blkfront_info *info) > > return 0; > > > > out_of_memory: > > - for (i = 0; i < BLK_RING_SIZE; i++) { > > + for (i = 0; i < BLK_RING_SIZE(info); i++) { > > kfree(info->shadow[i].grants_used); > > info->shadow[i].grants_used = NULL; > > kfree(info->shadow[i].sg); > > @@ -2089,6 +2140,12 @@ static int __init xlblk_init(void) > > if (!xen_domain()) > > return -ENODEV; > > > > + if (xen_blkif_max_ring_order > XENBUS_MAX_RING_PAGE_ORDER) > { > > + pr_info("Invalid max_ring_order (%d), will use default max: > %d.\n", > > + xen_blkif_max_ring_order, > XENBUS_MAX_RING_PAGE_ORDER); > > + xen_blkif_max_ring_order = 0; > > + } > > + > > if (!xen_has_pv_disk_devices()) > > return -ENODEV; > > > >