| Message ID | 1446812535-10567-5-git-send-email-vishnu.ps@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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; return 0; +out_blk_reg: + del_gendisk(z2ram_gendisk); +out_add_disk: out_queue: 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);
This patch handles blk_register_region() & add_disk() return value. Earlier these function doesn't handle error cases, now it is added, so the callers of this function should also handle it. Verfied on X86 based ubuntu machine. This patch depends on [PATCH 1/8] block/genhd.c: Add error handling Signed-off-by: Vishnu Pratap Singh <vishnu.ps@samsung.com> --- drivers/block/z2ram.c | 12 ++++++++++-- drivers/block/zram/zram_drv.c | 9 ++++++--- 2 files changed, 16 insertions(+), 5 deletions(-)