From: Keith Busch <kbusch@xxxxxxxxxx> When multiple partitions are used, you may want to enforce different subsets of the available write hints for each partition. Provide a bitmap attribute of the available write hints, and allow an admin to write a different mask to set the partition's allowed write hints. Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx> --- block/bdev.c | 15 +++++++++++++ block/partitions/core.c | 46 +++++++++++++++++++++++++++++++++++++-- include/linux/blk_types.h | 1 + 3 files changed, 60 insertions(+), 2 deletions(-) diff --git a/block/bdev.c b/block/bdev.c index 738e3c8457e7f..5d23648db457b 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -414,6 +414,7 @@ void __init bdev_cache_init(void) struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) { + unsigned short max_write_hints; struct block_device *bdev; struct inode *inode; @@ -440,6 +441,20 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno) return NULL; } bdev->bd_disk = disk; + + max_write_hints = bdev_max_write_hints(bdev); + if (max_write_hints) { + int size = BITS_TO_LONGS(max_write_hints) * sizeof(long); + + bdev->write_hint_mask = kmalloc(size, GFP_KERNEL); + if (!bdev->write_hint_mask) { + free_percpu(bdev->bd_stats); + iput(inode); + return NULL; + } + memset(bdev->write_hint_mask, 0xff, size); + } + return bdev; } diff --git a/block/partitions/core.c b/block/partitions/core.c index 815ed33caa1b8..c0ea0a7b6fa87 100644 --- a/block/partitions/core.c +++ b/block/partitions/core.c @@ -203,6 +203,42 @@ static ssize_t part_discard_alignment_show(struct device *dev, return sprintf(buf, "%u\n", bdev_discard_alignment(dev_to_bdev(dev))); } +static ssize_t part_write_hint_mask_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct block_device *bdev = dev_to_bdev(dev); + unsigned short max_write_hints = bdev_max_write_hints(bdev); + + if (max_write_hints) + return sprintf(buf, "%*pb\n", max_write_hints, bdev->write_hint_mask); + else + return sprintf(buf, "0"); +} + +static ssize_t part_write_hint_mask_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct block_device *bdev = dev_to_bdev(dev); + unsigned short max_write_hints = bdev_max_write_hints(bdev); + unsigned long *new_mask; + int size; + + if (!max_write_hints) + return count; + + size = BITS_TO_LONGS(max_write_hints) * sizeof(long); + new_mask = kzalloc(size, GFP_KERNEL); + if (!new_mask) + return -ENOMEM; + + bitmap_parse(buf, count, new_mask, max_write_hints); + bitmap_copy(bdev->write_hint_mask, new_mask, max_write_hints); + + return count; +} + static DEVICE_ATTR(partition, 0444, part_partition_show, NULL); static DEVICE_ATTR(start, 0444, part_start_show, NULL); static DEVICE_ATTR(size, 0444, part_size_show, NULL); @@ -211,6 +247,8 @@ static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL); static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL); static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); +static DEVICE_ATTR(write_hint_mask, 0644, part_write_hint_mask_show, + part_write_hint_mask_store); #ifdef CONFIG_FAIL_MAKE_REQUEST static struct device_attribute dev_attr_fail = __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); @@ -225,6 +263,7 @@ static struct attribute *part_attrs[] = { &dev_attr_discard_alignment.attr, &dev_attr_stat.attr, &dev_attr_inflight.attr, + &dev_attr_write_hint_mask.attr, #ifdef CONFIG_FAIL_MAKE_REQUEST &dev_attr_fail.attr, #endif @@ -245,8 +284,11 @@ static const struct attribute_group *part_attr_groups[] = { static void part_release(struct device *dev) { - put_disk(dev_to_bdev(dev)->bd_disk); - bdev_drop(dev_to_bdev(dev)); + struct block_device *part = dev_to_bdev(dev); + + kfree(part->write_hint_mask); + put_disk(part->bd_disk); + bdev_drop(part); } static int part_uevent(const struct device *dev, struct kobj_uevent_env *env) diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 6737795220e18..af430e543f7f7 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -73,6 +73,7 @@ struct block_device { #ifdef CONFIG_SECURITY void *bd_security; #endif + unsigned long *write_hint_mask; /* * keep this out-of-line as it's both big and not needed in the fast * path -- 2.43.5