From e5b2bcb9bdee921f94aa04531d22c63eb23ce9a1 Mon Sep 17 00:00:00 2001 From: "kaf24@firebug.cl.cam.ac.uk" Date: Wed, 14 Jun 2006 11:44:09 +0100 Subject: [PATCH] [LINUX][BLK] front: More care over device teardown. 1. We must ensure gnttab callbacks are disabled and all work flushed before tearing down device state. A new gnttab interface call is added for this purpose. 2. blkif_free() must check for a request_queue before deref'ing it. Signed-off-by: Keir Fraser xen-unstable changeset: 10346:5552bc2c3716e9e0f57dbba80f61332b895a0f2a xen-unstable date: Wed Jun 14 11:19:53 2006 +0100 --- .../drivers/xen/blkfront/blkfront.c | 19 ++++++++++++++++++- .../drivers/xen/core/gnttab.c | 15 +++++++++++++++ linux-2.6-xen-sparse/include/xen/gnttab.h | 1 + 3 files changed, 34 insertions(+), 1 deletion(-) diff --git a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c index 3a92dbadd..bc23060f8 100644 --- a/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c +++ b/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c @@ -342,9 +342,21 @@ static void connect(struct blkfront_info *info) static void blkfront_closing(struct xenbus_device *dev) { struct blkfront_info *info = dev->data; + unsigned long flags; DPRINTK("blkfront_closing: %s removed\n", dev->nodename); + if (info->rq == NULL) + return; + + spin_lock_irqsave(&blkif_io_lock, flags); + /* No more blkif_request(). */ + blk_stop_queue(info->rq); + /* No more gnttab callback work. */ + gnttab_cancel_free_callback(&info->callback); + flush_scheduled_work(); + spin_unlock_irqrestore(&blkif_io_lock, flags); + xlvbd_del(info); xenbus_switch_state(dev, XenbusStateClosed); @@ -696,7 +708,12 @@ static void blkif_free(struct blkfront_info *info, int suspend) spin_lock_irq(&blkif_io_lock); info->connected = suspend ? BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED; - blk_stop_queue(info->rq); /* no more blkif_request() */ + /* No more blkif_request(). */ + if (info->rq) + blk_stop_queue(info->rq); + /* No more gnttab callback work. */ + gnttab_cancel_free_callback(&info->callback); + flush_scheduled_work(); spin_unlock_irq(&blkif_io_lock); /* Free resources associated with old device channel. */ diff --git a/linux-2.6-xen-sparse/drivers/xen/core/gnttab.c b/linux-2.6-xen-sparse/drivers/xen/core/gnttab.c index 4317a1518..917b7192b 100644 --- a/linux-2.6-xen-sparse/drivers/xen/core/gnttab.c +++ b/linux-2.6-xen-sparse/drivers/xen/core/gnttab.c @@ -359,6 +359,21 @@ gnttab_request_free_callback(struct gnttab_free_callback *callback, spin_unlock_irqrestore(&gnttab_list_lock, flags); } +void gnttab_cancel_free_callback(struct gnttab_free_callback *callback) +{ + struct gnttab_free_callback **pcb; + unsigned long flags; + + spin_lock_irqsave(&gnttab_list_lock, flags); + for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) { + if (*pcb == callback) { + *pcb = callback->next; + break; + } + } + spin_unlock_irqrestore(&gnttab_list_lock, flags); +} + #ifndef __ia64__ static int map_pte_fn(pte_t *pte, struct page *pmd_page, unsigned long addr, void *data) diff --git a/linux-2.6-xen-sparse/include/xen/gnttab.h b/linux-2.6-xen-sparse/include/xen/gnttab.h index 63ad95451..de105c1bd 100644 --- a/linux-2.6-xen-sparse/include/xen/gnttab.h +++ b/linux-2.6-xen-sparse/include/xen/gnttab.h @@ -97,6 +97,7 @@ void gnttab_release_grant_reference(grant_ref_t *private_head, void gnttab_request_free_callback(struct gnttab_free_callback *callback, void (*fn)(void *), void *arg, u16 count); +void gnttab_cancel_free_callback(struct gnttab_free_callback *callback); void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid, unsigned long frame, int readonly); -- 2.39.5