On (11/06/15 17:52), Vishnu Pratap Singh wrote: > This patch adds error handling for blk_register_region(), > register_disk(), add_disk(), disk_alloc_events() & disk_add_events(). > add_disk() & register_disk() functions error handling is very much > needed as this is used mainly by many modules like mmc, zram, mtd, scsi etc. > But there is no error handling and it may cause stability issues also. hm... I came across "FIXME: error handling" comment in add_disk() some time ago and after a quick google search I found this: https://lkml.org/lkml/2007/7/24/207 >> The attached patch fixes the problem by changing the prototype of >> add_disk() and register_disk() to return errors. Al Viro wrote: > This is bogus. Just what would callers do with these error values? > Ignore them silently? Bail out? Can't do - at that point disk just > might have been opened already. add_disk() is the point of no return; > we are already past the last point where we could bail out. > drivers/block/z2ram.c | 12 ++++++++++-- > drivers/block/zram/zram_drv.c | 9 ++++++--- those are different drivers, split the patches (well, if add_disk() change actually makes sense). > 2 files changed, 16 insertions(+), 5 deletions(-) > > diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c > index 968f9e5..85e841f 100644 > --- a/drivers/block/z2ram.c > +++ b/drivers/block/z2ram.c > @@ -364,12 +364,20 @@ z2_init(void) > sprintf(z2ram_gendisk->disk_name, "z2ram"); > > z2ram_gendisk->queue = z2_queue; > - add_disk(z2ram_gendisk); > - blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE, > + ret = add_disk(z2ram_gendisk); > + if (ret) > + goto out_add_disk; > + > + ret = blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE, > z2_find, NULL, NULL); > + if (ret) > + goto out_blk_reg; A separate nitpick. z2_init() coding styles need to be 'fixed'. So the patch will not violate the kernel coding styles. ./scripts/checkpatch.pl WARNING: please, no spaces at the start of a line #113: FILE: drivers/block/z2ram.c:367: + ret = add_disk(z2ram_gendisk);$ WARNING: please, no spaces at the start of a line #114: FILE: drivers/block/z2ram.c:368: + if (ret)$ WARNING: please, no spaces at the start of a line #117: FILE: drivers/block/z2ram.c:371: + ret = blk_register_region(MKDEV(Z2RAM_MAJOR, 0), Z2MINOR_COUNT, THIS_MODULE,$ WARNING: please, no spaces at the start of a line #119: FILE: drivers/block/z2ram.c:373: + if (ret)$ total: 0 errors, 4 warnings, 50 lines checked > > return 0; > > +out_blk_reg: > + del_gendisk(z2ram_gendisk); > +out_add_disk: > out_queue: Hm... a fall-through empty `out_add_disk' label? -ss > put_disk(z2ram_gendisk); > out_disk: > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 81a557c..f3d7a49 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -1261,14 +1261,16 @@ static int zram_add(void) > zram->disk->queue->limits.discard_zeroes_data = 0; > queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue); > > - add_disk(zram->disk); > + ret = add_disk(zram->disk); > + if (ret) > + goto out_free_disk; > > ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, > &zram_disk_attr_group); > if (ret < 0) { > pr_err("Error creating sysfs group for device %d\n", > device_id); > - goto out_free_disk; > + goto out_del_disk; > } > strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor)); > zram->meta = NULL; > @@ -1277,8 +1279,9 @@ static int zram_add(void) > pr_info("Added device: %s\n", zram->disk->disk_name); > return device_id; > > -out_free_disk: > +out_del_disk: > del_gendisk(zram->disk); > +out_free_disk: > put_disk(zram->disk); > out_free_queue: > blk_cleanup_queue(queue); > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
