From 589b72894f53124a39d1bb3c0cecaf9dcabac417 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Mon, 9 Dec 2019 13:14:44 -0700 Subject: xen/blkfront: Adjust indentation in xlvbd_alloc_gendisk MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Clang warns: ../drivers/block/xen-blkfront.c:1117:4: warning: misleading indentation; statement is not part of the previous 'if' [-Wmisleading-indentation] nr_parts = PARTS_PER_DISK; ^ ../drivers/block/xen-blkfront.c:1115:3: note: previous statement is here if (err) ^ This is because there is a space at the beginning of this line; remove it so that the indentation is consistent according to the Linux kernel coding style and clang no longer warns. While we are here, the previous line has some trailing whitespace; clean that up as well. Fixes: c80a420995e7 ("xen-blkfront: handle Xen major numbers other than XENVBD") Link: https://github.com/ClangBuiltLinux/linux/issues/791 Signed-off-by: Nathan Chancellor Reviewed-by: Juergen Gross Acked-by: Roger Pau Monné Signed-off-by: Juergen Gross --- drivers/block/xen-blkfront.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index a74d03913822..c02be06c5299 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1113,8 +1113,8 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity, if (!VDEV_IS_EXTENDED(info->vdevice)) { err = xen_translate_vdev(info->vdevice, &minor, &offset); if (err) - return err; - nr_parts = PARTS_PER_DISK; + return err; + nr_parts = PARTS_PER_DISK; } else { minor = BLKIF_MINOR_EXT(info->vdevice); nr_parts = PARTS_PER_EXT_DISK; -- cgit v1.2.3 From c534374ecf044384ddd24474b91fd0d31e720464 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Wed, 11 Dec 2019 15:29:53 +0000 Subject: xenbus: move xenbus_dev_shutdown() into frontend code... ...and make it static xenbus_dev_shutdown() is seemingly intended to cause clean shutdown of PV frontends when a guest is rebooted. Indeed the function waits for a conpletion which is only set by a call to xenbus_frontend_closed(). This patch removes the shutdown() method from backends and moves xenbus_dev_shutdown() from xenbus_probe.c into xenbus_probe_frontend.c, renaming it appropriately and making it static. NOTE: In the case where the backend is running in a driver domain, the toolstack should have already terminated any frontends that may be using it (since Xen does not support re-startable PV driver domains) so xenbus_dev_shutdown() should never be called. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross --- drivers/xen/xenbus/xenbus.h | 2 -- drivers/xen/xenbus/xenbus_probe.c | 23 ----------------------- drivers/xen/xenbus/xenbus_probe_backend.c | 1 - drivers/xen/xenbus/xenbus_probe_frontend.c | 24 +++++++++++++++++++++++- 4 files changed, 23 insertions(+), 27 deletions(-) diff --git a/drivers/xen/xenbus/xenbus.h b/drivers/xen/xenbus/xenbus.h index d75a2385b37c..5f5b8a7d5b80 100644 --- a/drivers/xen/xenbus/xenbus.h +++ b/drivers/xen/xenbus/xenbus.h @@ -116,8 +116,6 @@ int xenbus_probe_devices(struct xen_bus_type *bus); void xenbus_dev_changed(const char *node, struct xen_bus_type *bus); -void xenbus_dev_shutdown(struct device *_dev); - int xenbus_dev_suspend(struct device *dev); int xenbus_dev_resume(struct device *dev); int xenbus_dev_cancel(struct device *dev); diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index c21be6e9d38a..5aa29396c9e3 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -281,29 +281,6 @@ int xenbus_dev_remove(struct device *_dev) } EXPORT_SYMBOL_GPL(xenbus_dev_remove); -void xenbus_dev_shutdown(struct device *_dev) -{ - struct xenbus_device *dev = to_xenbus_device(_dev); - unsigned long timeout = 5*HZ; - - DPRINTK("%s", dev->nodename); - - get_device(&dev->dev); - if (dev->state != XenbusStateConnected) { - pr_info("%s: %s: %s != Connected, skipping\n", - __func__, dev->nodename, xenbus_strstate(dev->state)); - goto out; - } - xenbus_switch_state(dev, XenbusStateClosing); - timeout = wait_for_completion_timeout(&dev->down, timeout); - if (!timeout) - pr_info("%s: %s timeout closing device\n", - __func__, dev->nodename); - out: - put_device(&dev->dev); -} -EXPORT_SYMBOL_GPL(xenbus_dev_shutdown); - int xenbus_register_driver_common(struct xenbus_driver *drv, struct xen_bus_type *bus, struct module *owner, const char *mod_name) diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c index b0bed4faf44c..14876faff3b0 100644 --- a/drivers/xen/xenbus/xenbus_probe_backend.c +++ b/drivers/xen/xenbus/xenbus_probe_backend.c @@ -198,7 +198,6 @@ static struct xen_bus_type xenbus_backend = { .uevent = xenbus_uevent_backend, .probe = xenbus_dev_probe, .remove = xenbus_dev_remove, - .shutdown = xenbus_dev_shutdown, .dev_groups = xenbus_dev_groups, }, }; diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c index a7d90a719cea..8a1650bbe18f 100644 --- a/drivers/xen/xenbus/xenbus_probe_frontend.c +++ b/drivers/xen/xenbus/xenbus_probe_frontend.c @@ -126,6 +126,28 @@ static int xenbus_frontend_dev_probe(struct device *dev) return xenbus_dev_probe(dev); } +static void xenbus_frontend_dev_shutdown(struct device *_dev) +{ + struct xenbus_device *dev = to_xenbus_device(_dev); + unsigned long timeout = 5*HZ; + + DPRINTK("%s", dev->nodename); + + get_device(&dev->dev); + if (dev->state != XenbusStateConnected) { + pr_info("%s: %s: %s != Connected, skipping\n", + __func__, dev->nodename, xenbus_strstate(dev->state)); + goto out; + } + xenbus_switch_state(dev, XenbusStateClosing); + timeout = wait_for_completion_timeout(&dev->down, timeout); + if (!timeout) + pr_info("%s: %s timeout closing device\n", + __func__, dev->nodename); + out: + put_device(&dev->dev); +} + static const struct dev_pm_ops xenbus_pm_ops = { .suspend = xenbus_dev_suspend, .resume = xenbus_frontend_dev_resume, @@ -146,7 +168,7 @@ static struct xen_bus_type xenbus_frontend = { .uevent = xenbus_uevent_frontend, .probe = xenbus_frontend_dev_probe, .remove = xenbus_dev_remove, - .shutdown = xenbus_dev_shutdown, + .shutdown = xenbus_frontend_dev_shutdown, .dev_groups = xenbus_dev_groups, .pm = &xenbus_pm_ops, -- cgit v1.2.3 From 672b7763cb2c723fd6f92a3879cc60d2fb11e56a Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Wed, 11 Dec 2019 15:29:54 +0000 Subject: xenbus: limit when state is forced to closed If a driver probe() fails then leave the xenstore state alone. There is no reason to modify it as the failure may be due to transient resource allocation issues and hence a subsequent probe() may succeed. If the driver supports re-binding then only force state to closed during remove() only in the case when the toolstack may need to clean up. This can be detected by checking whether the state in xenstore has been set to closing prior to device removal. NOTE: Re-bind support is indicated by new boolean in struct xenbus_driver, which defaults to false. Subsequent patches will add support to some backend drivers. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross --- drivers/xen/xenbus/xenbus_probe.c | 12 ++++++++++-- include/xen/xenbus.h | 1 + 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c index 5aa29396c9e3..378486b79f96 100644 --- a/drivers/xen/xenbus/xenbus_probe.c +++ b/drivers/xen/xenbus/xenbus_probe.c @@ -255,7 +255,6 @@ fail_put: module_put(drv->driver.owner); fail: xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); - xenbus_switch_state(dev, XenbusStateClosed); return err; } EXPORT_SYMBOL_GPL(xenbus_dev_probe); @@ -276,7 +275,16 @@ int xenbus_dev_remove(struct device *_dev) free_otherend_details(dev); - xenbus_switch_state(dev, XenbusStateClosed); + /* + * If the toolstack has forced the device state to closing then set + * the state to closed now to allow it to be cleaned up. + * Similarly, if the driver does not support re-bind, set the + * closed. + */ + if (!drv->allow_rebind || + xenbus_read_driver_state(dev->nodename) == XenbusStateClosing) + xenbus_switch_state(dev, XenbusStateClosed); + return 0; } EXPORT_SYMBOL_GPL(xenbus_dev_remove); diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h index 869c816d5f8c..24228a102141 100644 --- a/include/xen/xenbus.h +++ b/include/xen/xenbus.h @@ -93,6 +93,7 @@ struct xenbus_device_id struct xenbus_driver { const char *name; /* defaults to ids[0].devicetype */ const struct xenbus_device_id *ids; + bool allow_rebind; /* avoid setting xenstore closed during remove */ int (*probe)(struct xenbus_device *dev, const struct xenbus_device_id *id); void (*otherend_changed)(struct xenbus_device *dev, -- cgit v1.2.3 From 1ee54195a305fae3955642af8528bdf67496d353 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Wed, 11 Dec 2019 15:29:55 +0000 Subject: xen/interface: re-define FRONT/BACK_RING_ATTACH() Currently these macros are defined to re-initialize a front/back ring (respectively) to values read from the shared ring in such a way that any requests/responses that are added to the shared ring whilst the front/back is detached will be skipped over. This, in general, is not a desirable semantic since most frontend implementations will eventually block waiting for a response which would either never appear or never be processed. Since the macros are currently unused, take this opportunity to re-define them to re-initialize a front/back ring using specified values. This also allows FRONT/BACK_RING_INIT() to be re-defined in terms of FRONT/BACK_RING_ATTACH() using a specified value of 0. NOTE: BACK_RING_ATTACH() will be used directly in a subsequent patch. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross --- include/xen/interface/io/ring.h | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h index 3f40501fc60b..2af7a1cd6658 100644 --- a/include/xen/interface/io/ring.h +++ b/include/xen/interface/io/ring.h @@ -125,35 +125,24 @@ struct __name##_back_ring { \ memset((_s)->pad, 0, sizeof((_s)->pad)); \ } while(0) -#define FRONT_RING_INIT(_r, _s, __size) do { \ - (_r)->req_prod_pvt = 0; \ - (_r)->rsp_cons = 0; \ +#define FRONT_RING_ATTACH(_r, _s, _i, __size) do { \ + (_r)->req_prod_pvt = (_i); \ + (_r)->rsp_cons = (_i); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \ (_r)->sring = (_s); \ } while (0) -#define BACK_RING_INIT(_r, _s, __size) do { \ - (_r)->rsp_prod_pvt = 0; \ - (_r)->req_cons = 0; \ - (_r)->nr_ents = __RING_SIZE(_s, __size); \ - (_r)->sring = (_s); \ -} while (0) +#define FRONT_RING_INIT(_r, _s, __size) FRONT_RING_ATTACH(_r, _s, 0, __size) -/* Initialize to existing shared indexes -- for recovery */ -#define FRONT_RING_ATTACH(_r, _s, __size) do { \ - (_r)->sring = (_s); \ - (_r)->req_prod_pvt = (_s)->req_prod; \ - (_r)->rsp_cons = (_s)->rsp_prod; \ +#define BACK_RING_ATTACH(_r, _s, _i, __size) do { \ + (_r)->rsp_prod_pvt = (_i); \ + (_r)->req_cons = (_i); \ (_r)->nr_ents = __RING_SIZE(_s, __size); \ -} while (0) - -#define BACK_RING_ATTACH(_r, _s, __size) do { \ (_r)->sring = (_s); \ - (_r)->rsp_prod_pvt = (_s)->rsp_prod; \ - (_r)->req_cons = (_s)->req_prod; \ - (_r)->nr_ents = __RING_SIZE(_s, __size); \ } while (0) +#define BACK_RING_INIT(_r, _s, __size) BACK_RING_ATTACH(_r, _s, 0, __size) + /* How big is this ring? */ #define RING_SIZE(_r) \ ((_r)->nr_ents) -- cgit v1.2.3 From f4eef1b652eeb850a0f44e8f985cc4153a0c0265 Mon Sep 17 00:00:00 2001 From: Paul Durrant Date: Wed, 11 Dec 2019 15:29:56 +0000 Subject: xen-blkback: support dynamic unbind/bind MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit By simply re-attaching to shared rings during connect_ring() rather than assuming they are freshly allocated (i.e assuming the counters are zero) it is possible for vbd instances to be unbound and re-bound from and to (respectively) a running guest. This has been tested by running: while true; do fio --name=randwrite --ioengine=libaio --iodepth=16 \ --rw=randwrite --bs=4k --direct=1 --size=1G --verify=crc32; done in a PV guest whilst running: while true; do echo vbd-$DOMID-$VBD >unbind; echo unbound; sleep 5; echo vbd-$DOMID-$VBD >bind; echo bound; sleep 3; done in dom0 from /sys/bus/xen-backend/drivers/vbd to continuously unbind and re-bind its system disk image. This is a highly useful feature for a backend module as it allows it to be unloaded and re-loaded (i.e. updated) without requiring domUs to be halted. This was also tested by running: while true; do echo vbd-$DOMID-$VBD >unbind; echo unbound; sleep 5; rmmod xen-blkback; echo unloaded; sleep 1; modprobe xen-blkback; echo bound; cd $(pwd); sleep 3; done in dom0 whilst running the same loop as above in the (single) PV guest. Some (less stressful) testing has also been done using a Windows HVM guest with the latest 9.0 PV drivers installed. Signed-off-by: Paul Durrant Reviewed-by: Juergen Gross Reviewed-by: Roger Pau Monné Signed-off-by: Juergen Gross --- drivers/block/xen-blkback/xenbus.c | 56 ++++++++++++++++++++++++++------------ 1 file changed, 38 insertions(+), 18 deletions(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index d6a6adfd5159..4c5d99f87813 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -190,6 +190,9 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, { int err; struct xen_blkif *blkif = ring->blkif; + const struct blkif_common_sring *sring_common; + RING_IDX rsp_prod, req_prod; + unsigned int size; /* Already connected through? */ if (ring->irq) @@ -200,46 +203,62 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref, if (err < 0) return err; + sring_common = (struct blkif_common_sring *)ring->blk_ring; + rsp_prod = READ_ONCE(sring_common->rsp_prod); + req_prod = READ_ONCE(sring_common->req_prod); + switch (blkif->blk_protocol) { case BLKIF_PROTOCOL_NATIVE: { - struct blkif_sring *sring; - sring = (struct blkif_sring *)ring->blk_ring; - BACK_RING_INIT(&ring->blk_rings.native, sring, - XEN_PAGE_SIZE * nr_grefs); + struct blkif_sring *sring_native = + (struct blkif_sring *)ring->blk_ring; + + BACK_RING_ATTACH(&ring->blk_rings.native, sring_native, + rsp_prod, XEN_PAGE_SIZE * nr_grefs); + size = __RING_SIZE(sring_native, XEN_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 *)ring->blk_ring; - BACK_RING_INIT(&ring->blk_rings.x86_32, sring_x86_32, - XEN_PAGE_SIZE * nr_grefs); + struct blkif_x86_32_sring *sring_x86_32 = + (struct blkif_x86_32_sring *)ring->blk_ring; + + BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32, + rsp_prod, XEN_PAGE_SIZE * nr_grefs); + size = __RING_SIZE(sring_x86_32, XEN_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 *)ring->blk_ring; - BACK_RING_INIT(&ring->blk_rings.x86_64, sring_x86_64, - XEN_PAGE_SIZE * nr_grefs); + struct blkif_x86_64_sring *sring_x86_64 = + (struct blkif_x86_64_sring *)ring->blk_ring; + + BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64, + rsp_prod, XEN_PAGE_SIZE * nr_grefs); + size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs); break; } default: BUG(); } + err = -EIO; + if (req_prod - rsp_prod > size) + goto fail; + err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, xen_blkif_be_int, 0, "blkif-backend", ring); - if (err < 0) { - xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); - ring->blk_rings.common.sring = NULL; - return err; - } + if (err < 0) + goto fail; ring->irq = err; return 0; + +fail: + xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring); + ring->blk_rings.common.sring = NULL; + return err; } static int xen_blkif_disconnect(struct xen_blkif *blkif) @@ -1131,7 +1150,8 @@ static struct xenbus_driver xen_blkbk_driver = { .ids = xen_blkbk_ids, .probe = xen_blkbk_probe, .remove = xen_blkbk_remove, - .otherend_changed = frontend_changed + .otherend_changed = frontend_changed, + .allow_rebind = true, }; int xen_blkif_xenbus_init(void) -- cgit v1.2.3 From d6bd6cf9feb81737f9f64d2c1acf98fdaacebad1 Mon Sep 17 00:00:00 2001 From: Aditya Pakki Date: Tue, 17 Dec 2019 14:53:56 -0600 Subject: xen/grant-table: remove multiple BUG_ON on gnttab_interface gnttab_request_version() always sets the gnttab_interface variable and the assertions to check for empty gnttab_interface is unnecessary. The patch eliminates multiple such assertions. Signed-off-by: Aditya Pakki Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross --- drivers/xen/grant-table.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 49b381e104ef..7b36b51cdb9f 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -664,7 +664,6 @@ static int grow_gnttab_list(unsigned int more_frames) unsigned int nr_glist_frames, new_nr_glist_frames; unsigned int grefs_per_frame; - BUG_ON(gnttab_interface == NULL); grefs_per_frame = gnttab_interface->grefs_per_grant_frame; new_nr_grant_frames = nr_grant_frames + more_frames; @@ -1160,7 +1159,6 @@ EXPORT_SYMBOL_GPL(gnttab_unmap_refs_sync); static unsigned int nr_status_frames(unsigned int nr_grant_frames) { - BUG_ON(gnttab_interface == NULL); return gnttab_frames(nr_grant_frames, SPP); } @@ -1388,7 +1386,6 @@ static int gnttab_expand(unsigned int req_entries) int rc; unsigned int cur, extra; - BUG_ON(gnttab_interface == NULL); cur = nr_grant_frames; extra = ((req_entries + gnttab_interface->grefs_per_grant_frame - 1) / gnttab_interface->grefs_per_grant_frame); @@ -1423,7 +1420,6 @@ int gnttab_init(void) /* Determine the maximum number of frames required for the * grant reference free list on the current hypervisor. */ - BUG_ON(gnttab_interface == NULL); max_nr_glist_frames = (max_nr_grant_frames * gnttab_interface->grefs_per_grant_frame / RPP); -- cgit v1.2.3