[PATCH 2/4] f2fs: add sanity check for ipu_policy

[Yangtao Li <frank.li@vivo.com>]

Disallow the value set beyond the range, and disallow to change
the value in lfs mode.

BTW, convert open code to use BIT().

Signed-off-by: Yangtao Li <frank.li@vivo.com>
---
 fs/f2fs/segment.h |  1 +
 fs/f2fs/sysfs.c   | 11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 0b0eb8f03cba..d73e988566a5 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -681,6 +681,7 @@ enum {
 	F2FS_IPU_ASYNC,
 	F2FS_IPU_NOCACHE,
 	F2FS_IPU_HONOR_OPU_WRITE,
+	F2FS_IPU_MAX,
 };
 
 #define F2FS_IPU_POLICY(name)					\
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index bdc761f36310..576e6416ffb9 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -452,7 +452,7 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 	if (ret < 0)
 		return ret;
 #ifdef CONFIG_F2FS_FAULT_INJECTION
-	if (a->struct_type == FAULT_INFO_TYPE && t >= (1 << FAULT_MAX))
+	if (a->struct_type == FAULT_INFO_TYPE && t >= BIT(FAULT_MAX))
 		return -EINVAL;
 	if (a->struct_type == FAULT_INFO_RATE && t >= UINT_MAX)
 		return -EINVAL;
@@ -706,6 +706,15 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 		return count;
 	}
 
+	if (!strcmp(a->attr.name, "ipu_policy")) {
+		if (F2FS_OPTION(sbi).fs_mode == FS_MODE_LFS)
+			return -EINVAL;
+		if (t >= BIT(F2FS_IPU_MAX))
+			return -EINVAL;
+		SM_I(sbi)->ipu_policy = (unsigned int)t;
+		return count;
+	}
+
 	*ui = (unsigned int)t;
 
 	return count;
-- 
2.25.1