diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/xen-blkfront.c | 58 |
1 files changed, 46 insertions, 12 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 60eed4bdd2e4..e4fb3374dcd2 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -141,14 +141,36 @@ static int get_id_from_freelist(struct blkfront_info *info) return free; } -static void add_id_to_freelist(struct blkfront_info *info, +static int add_id_to_freelist(struct blkfront_info *info, unsigned long id) { + if (info->shadow[id].req.u.rw.id != id) + return -EINVAL; + if (info->shadow[id].request == NULL) + return -EINVAL; info->shadow[id].req.u.rw.id = info->shadow_free; info->shadow[id].request = NULL; info->shadow_free = id; + return 0; } +static const char *op_name(int op) +{ + static const char *const names[] = { + [BLKIF_OP_READ] = "read", + [BLKIF_OP_WRITE] = "write", + [BLKIF_OP_WRITE_BARRIER] = "barrier", + [BLKIF_OP_FLUSH_DISKCACHE] = "flush", + [BLKIF_OP_DISCARD] = "discard" }; + + if (op < 0 || op >= ARRAY_SIZE(names)) + return "unknown"; + + if (!names[op]) + return "reserved"; + + return names[op]; +} static int xlbd_reserve_minors(unsigned int minor, unsigned int nr) { unsigned int end = minor + nr; @@ -746,20 +768,36 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) bret = RING_GET_RESPONSE(&info->ring, i); id = bret->id; + /* + * The backend has messed up and given us an id that we would + * never have given to it (we stamp it up to BLK_RING_SIZE - + * look in get_id_from_freelist. + */ + if (id >= BLK_RING_SIZE) { + 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 + * the id is busted. */ + continue; + } req = info->shadow[id].request; if (bret->operation != BLKIF_OP_DISCARD) blkif_completion(&info->shadow[id]); - add_id_to_freelist(info, id); + if (add_id_to_freelist(info, id)) { + WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n", + info->gd->disk_name, op_name(bret->operation), id); + continue; + } error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO; switch (bret->operation) { case BLKIF_OP_DISCARD: if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { struct request_queue *rq = info->rq; - printk(KERN_WARNING "blkfront: %s: discard op failed\n", - info->gd->disk_name); + printk(KERN_WARNING "blkfront: %s: %s op failed\n", + info->gd->disk_name, op_name(bret->operation)); error = -EOPNOTSUPP; info->feature_discard = 0; info->feature_secdiscard = 0; @@ -771,18 +809,14 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) case BLKIF_OP_FLUSH_DISKCACHE: case BLKIF_OP_WRITE_BARRIER: if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) { - printk(KERN_WARNING "blkfront: %s: write %s op failed\n", - info->flush_op == BLKIF_OP_WRITE_BARRIER ? - "barrier" : "flush disk cache", - info->gd->disk_name); + printk(KERN_WARNING "blkfront: %s: %s op failed\n", + info->gd->disk_name, op_name(bret->operation)); error = -EOPNOTSUPP; } if (unlikely(bret->status == BLKIF_RSP_ERROR && info->shadow[id].req.u.rw.nr_segments == 0)) { - printk(KERN_WARNING "blkfront: %s: empty write %s op failed\n", - info->flush_op == BLKIF_OP_WRITE_BARRIER ? - "barrier" : "flush disk cache", - info->gd->disk_name); + printk(KERN_WARNING "blkfront: %s: empty %s op failed\n", + info->gd->disk_name, op_name(bret->operation)); error = -EOPNOTSUPP; } if (unlikely(error)) { |