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Subject[PATCH v3 2/5] sysctl: kdoc'ify sysctl_writes_strict
Date
Document the different sysctl_writes_strict modes in code.

Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
kernel/sysctl.c | 29 +++++++++++++++++++++++++----
1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4dfba1a76cc3..02725178694a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -174,11 +174,32 @@ extern int no_unaligned_warning;

#ifdef CONFIG_PROC_SYSCTL

-#define SYSCTL_WRITES_LEGACY -1
-#define SYSCTL_WRITES_WARN 0
-#define SYSCTL_WRITES_STRICT 1
+/**
+ * enum sysctl_writes_mode - supported sysctl write modes
+ *
+ * @SYSCTL_WRITES_LEGACY: each write syscall must fully contain the sysctl value
+ * to be written, and multiple writes on the same sysctl file descriptor
+ * will rewrite the sysctl value, regardless of file position. No warning
+ * is issued when the initial position is not 0.
+ * @SYSCTL_WRITES_WARN: same as above but warn when the initial file position is
+ * not 0.
+ * @SYSCTL_WRITES_STRICT: writes to numeric sysctl entries must always be at
+ * file position 0 and the value must be fully contained in the buffer
+ * sent to the write syscall. If dealing with strings respect the file
+ * position, but restrict this to the max length of the buffer, anything
+ * passed the max lenght will be ignored. Multiple writes will append
+ * to the buffer.
+ *
+ * These write modes control how current file position affects the behavior of
+ * updating sysctl values through the proc interface on each write.
+ */
+enum sysctl_writes_mode {
+ SYSCTL_WRITES_LEGACY = -1,
+ SYSCTL_WRITES_WARN = 0,
+ SYSCTL_WRITES_STRICT = 1,
+};

-static int sysctl_writes_strict = SYSCTL_WRITES_STRICT;
+static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;

static int proc_do_cad_pid(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
--
2.11.0
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