From e77c78c02290c27925f67cd35b497e99ee0d6fe1 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 5 Apr 2012 16:37:22 +0100 Subject: [PATCH 1/2] xen-blkfront: properly name all devices - devices beyond xvdzz didn't get proper names assigned at all - extended devices with minors not representable within the kernel's major/minor bit split spilled into foreign majors Signed-off-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkfront.c | 40 ++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 18 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 4e86393a09cf..4f2b46052976 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -526,6 +526,14 @@ static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset) return 0; } +static char *encode_disk_name(char *ptr, unsigned int n) +{ + if (n >= 26) + ptr = encode_disk_name(ptr, n / 26 - 1); + *ptr = 'a' + n % 26; + return ptr + 1; +} + static int xlvbd_alloc_gendisk(blkif_sector_t capacity, struct blkfront_info *info, u16 vdisk_info, u16 sector_size) @@ -536,6 +544,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity, unsigned int offset; int minor; int nr_parts; + char *ptr; BUG_ON(info->gd != NULL); BUG_ON(info->rq != NULL); @@ -560,7 +569,11 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity, "emulated IDE disks,\n\t choose an xvd device name" "from xvde on\n", info->vdevice); } - err = -ENODEV; + if (minor >> MINORBITS) { + pr_warn("blkfront: %#x's minor (%#x) out of range; ignoring\n", + info->vdevice, minor); + return -ENODEV; + } if ((minor % nr_parts) == 0) nr_minors = nr_parts; @@ -574,23 +587,14 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity, if (gd == NULL) goto release; - if (nr_minors > 1) { - if (offset < 26) - sprintf(gd->disk_name, "%s%c", DEV_NAME, 'a' + offset); - else - sprintf(gd->disk_name, "%s%c%c", DEV_NAME, - 'a' + ((offset / 26)-1), 'a' + (offset % 26)); - } else { - if (offset < 26) - sprintf(gd->disk_name, "%s%c%d", DEV_NAME, - 'a' + offset, - minor & (nr_parts - 1)); - else - sprintf(gd->disk_name, "%s%c%c%d", DEV_NAME, - 'a' + ((offset / 26) - 1), - 'a' + (offset % 26), - minor & (nr_parts - 1)); - } + strcpy(gd->disk_name, DEV_NAME); + ptr = encode_disk_name(gd->disk_name + sizeof(DEV_NAME) - 1, offset); + BUG_ON(ptr >= gd->disk_name + DISK_NAME_LEN); + if (nr_minors > 1) + *ptr = 0; + else + snprintf(ptr, gd->disk_name + DISK_NAME_LEN - ptr, + "%d", minor & (nr_parts - 1)); gd->major = XENVBD_MAJOR; gd->first_minor = minor; From 8605067fb9b8e34aecf44ec258657c9cc009fc5a Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Thu, 5 Apr 2012 16:04:52 +0100 Subject: [PATCH 2/2] xen-blkfront: module exit handling adjustments The blkdev major must be released upon exit, or else the module can't attach to devices using the same majors upon being loaded again. Also avoid leaking the minor tracking bitmap. Signed-off-by: Jan Beulich Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkfront.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 4f2b46052976..60eed4bdd2e4 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1500,7 +1500,9 @@ module_init(xlblk_init); static void __exit xlblk_exit(void) { - return xenbus_unregister_driver(&blkfront_driver); + xenbus_unregister_driver(&blkfront_driver); + unregister_blkdev(XENVBD_MAJOR, DEV_NAME); + kfree(minors); } module_exit(xlblk_exit);