From: Stefan Roesch shr@devkernel.io
mainline inclusion from mainline-v6.2-rc1 commit 27bbe9d48d4e298864e18b39f091342c68b81637 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAN96I
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Add a new knob to /sys/class/bdi/<bdi>/strict_limit. This new knob allows to set/unset the flag BDI_CAP_STRICTLIMIT in the bdi capabilities.
Link: https://lkml.kernel.org/r/20221119005215.3052436-3-shr@devkernel.io Signed-off-by: Stefan Roesch shr@devkernel.io Cc: Chris Mason clm@meta.com Cc: Jens Axboe axboe@kernel.dk Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- mm/backing-dev.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 5f4f16dbff9d..d2a7b3dbfcda 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -207,11 +207,40 @@ static ssize_t stable_pages_required_show(struct device *dev, } static DEVICE_ATTR_RO(stable_pages_required);
+static ssize_t strict_limit_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + unsigned int strict_limit; + ssize_t ret; + + ret = kstrtouint(buf, 10, &strict_limit); + if (ret < 0) + return ret; + + ret = bdi_set_strict_limit(bdi, strict_limit); + if (!ret) + ret = count; + + return ret; +} + +static ssize_t strict_limit_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", + !!(bdi->capabilities & BDI_CAP_STRICTLIMIT)); +} +static DEVICE_ATTR_RW(strict_limit); + static struct attribute *bdi_dev_attrs[] = { &dev_attr_read_ahead_kb.attr, &dev_attr_min_ratio.attr, &dev_attr_max_ratio.attr, &dev_attr_stable_pages_required.attr, + &dev_attr_strict_limit.attr, NULL, }; ATTRIBUTE_GROUPS(bdi_dev);