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sysctl: Replace UINT converter macros with functions

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Replace the SYSCTL_USER_TO_KERN_UINT_CONV and SYSCTL_UINT_CONV_CUSTOM
macros with functions with the same logic. This makes debugging easier
and aligns with the functions preference described in coding-style.rst.
Update the only user of this API: pipe.c.

Signed-off-by: Joel Granados <joel.granados@kernel.org>
This commit is contained in:
Joel Granados 2025-11-28 21:53:00 +01:00
parent 6036dc03c3
commit 8fc344a5af
3 changed files with 148 additions and 77 deletions
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22
fs/pipe.c
View File

@ -1481,10 +1481,24 @@ static struct file_system_type pipe_fs_type = {
};
#ifdef CONFIG_SYSCTL
static SYSCTL_USER_TO_KERN_UINT_CONV(_pipe_maxsz, round_pipe_size)
static SYSCTL_UINT_CONV_CUSTOM(_pipe_maxsz,
sysctl_user_to_kern_uint_conv_pipe_maxsz,
sysctl_kern_to_user_uint_conv, true)
static ulong round_pipe_size_ul(ulong size)
{
return round_pipe_size(size);
}
static int u2k_pipe_maxsz(const ulong *u_ptr, uint *k_ptr)
{
return proc_uint_u2k_conv_uop(u_ptr, k_ptr, round_pipe_size_ul);
}
static int do_proc_uint_conv_pipe_maxsz(ulong *u_ptr, uint *k_ptr,
int dir, const struct ctl_table *table)
{
return proc_uint_conv(u_ptr, k_ptr, dir, table, true,
u2k_pipe_maxsz,
proc_uint_k2u_conv);
}
static int proc_dopipe_max_size(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)

63
include/linux/sysctl.h
View File

@ -135,45 +135,6 @@ int do_proc_int_conv##name(bool *negp, unsigned long *u_ptr, int *k_ptr,\
return user_to_kern(negp, u_ptr, k_ptr); \
return 0; \
}
#define SYSCTL_USER_TO_KERN_UINT_CONV(name, u_ptr_op) \
int sysctl_user_to_kern_uint_conv##name(const unsigned long *u_ptr,\
unsigned int *k_ptr) \
{ \
unsigned long u = u_ptr_op(*u_ptr); \
if (u > UINT_MAX) \
return -EINVAL; \
WRITE_ONCE(*k_ptr, u); \
return 0; \
}
#define SYSCTL_UINT_CONV_CUSTOM(name, user_to_kern, kern_to_user, \
k_ptr_range_check) \
int do_proc_uint_conv##name(unsigned long *u_ptr, unsigned int *k_ptr, \
int dir, const struct ctl_table *tbl) \
{ \
if (SYSCTL_KERN_TO_USER(dir)) \
return kern_to_user(u_ptr, k_ptr); \
\
if (k_ptr_range_check) { \
unsigned int tmp_k; \
int ret; \
if (!tbl) \
return -EINVAL; \
ret = user_to_kern(u_ptr, &tmp_k); \
if (ret) \
return ret; \
if ((tbl->extra1 && \
*(unsigned int *)tbl->extra1 > tmp_k) || \
(tbl->extra2 && \
*(unsigned int *)tbl->extra2 < tmp_k)) \
return -ERANGE; \
WRITE_ONCE(*k_ptr, tmp_k); \
} else \
return user_to_kern(u_ptr, k_ptr); \
return 0; \
}
#else // CONFIG_PROC_SYSCTL
#define SYSCTL_USER_TO_KERN_INT_CONV(name, u_ptr_op) \
int sysctl_user_to_kern_int_conv##name(const bool *negp, \
@ -199,24 +160,8 @@ int do_proc_int_conv##name(bool *negp, unsigned long *u_ptr, int *k_ptr,\
return -ENOSYS; \
}
#define SYSCTL_USER_TO_KERN_UINT_CONV(name, u_ptr_op) \
int sysctl_user_to_kern_uint_conv##name(const unsigned long *u_ptr,\
unsigned int *k_ptr) \
{ \
return -ENOSYS; \
}
#define SYSCTL_UINT_CONV_CUSTOM(name, user_to_kern, kern_to_user, \
k_ptr_range_check) \
int do_proc_uint_conv##name(unsigned long *u_ptr, unsigned int *k_ptr, \
int dir, const struct ctl_table *tbl) \
{ \
return -ENOSYS; \
}
#endif // CONFIG_PROC_SYSCTL
extern const unsigned long sysctl_long_vals[];
typedef int proc_handler(const struct ctl_table *ctl, int write, void *buffer,
@ -239,6 +184,13 @@ int proc_douintvec_conv(const struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos,
int (*conv)(unsigned long *lvalp, unsigned int *valp,
int write, const struct ctl_table *table));
int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr);
int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr,
ulong (*u_ptr_op)(const ulong));
int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,
const struct ctl_table *tbl, bool k_ptr_range_check,
int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr),
int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr));
int proc_dou8vec_minmax(const struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
@ -249,7 +201,6 @@ int proc_doulongvec_minmax_conv(const struct ctl_table *table, int dir,
int proc_do_large_bitmap(const struct ctl_table *, int, void *, size_t *, loff_t *);
int proc_do_static_key(const struct ctl_table *table, int write, void *buffer,
size_t *lenp, loff_t *ppos);
int sysctl_kern_to_user_uint_conv(unsigned long *u_ptr, const unsigned int *k_ptr);
/*
* Register a set of sysctl names by calling register_sysctl

140
kernel/sysctl.c
View File

@ -354,6 +354,110 @@ static void proc_put_char(void **buf, size_t *size, char c)
}
}
/**
* proc_uint_u2k_conv_uop - Assign user value to a kernel pointer
*
* @u_ptr: pointer to user space variable
* @k_ptr: pointer to kernel variable
* @u_ptr_op: execute this function before assigning to k_ptr
*
* Uses WRITE_ONCE to assign value to k_ptr. Executes u_ptr_op if
* not NULL. Check that the values are less than UINT_MAX to avoid
* having to support wrap around from userspace.
*
* returns 0 on success.
*/
int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr,
ulong (*u_ptr_op)(const ulong))
{
ulong u = u_ptr_op ? u_ptr_op(*u_ptr) : *u_ptr;
if (u > UINT_MAX)
return -EINVAL;
WRITE_ONCE(*k_ptr, u);
return 0;
}
/**
* proc_uint_k2u_conv - Assign kernel value to a user space pointer
*
* @u_ptr: pointer to user space variable
* @k_ptr: pointer to kernel variable
*
* Uses READ_ONCE to assign value to u_ptr.
*
* returns 0 on success.
*/
int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr)
{
uint val = READ_ONCE(*k_ptr);
*u_ptr = (ulong)val;
return 0;
}
/**
* proc_uint_conv - Change user or kernel pointer based on direction
*
* @u_ptr: pointer to user variable
* @k_ptr: pointer to kernel variable
* @dir: %TRUE if this is a write to the sysctl file
* @tbl: the sysctl table
* @k_ptr_range_check: Check range for k_ptr when %TRUE
* @user_to_kern: Callback used to assign value from user to kernel var
* @kern_to_user: Callback used to assign value from kernel to user var
*
* When direction is kernel to user, then the u_ptr is modified.
* When direction is user to kernel, then the k_ptr is modified.
*
* Returns 0 on success
*/
int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,
const struct ctl_table *tbl, bool k_ptr_range_check,
int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr),
int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr))
{
if (SYSCTL_KERN_TO_USER(dir))
return kern_to_user(u_ptr, k_ptr);
if (k_ptr_range_check) {
uint tmp_k;
int ret;
if (!tbl)
return -EINVAL;
ret = user_to_kern(u_ptr, &tmp_k);
if (ret)
return ret;
if ((tbl->extra1 &&
*(uint *)tbl->extra1 > tmp_k) ||
(tbl->extra2 &&
*(uint *)tbl->extra2 < tmp_k))
return -ERANGE;
WRITE_ONCE(*k_ptr, tmp_k);
} else
return user_to_kern(u_ptr, k_ptr);
return 0;
}
static int proc_uint_u2k_conv(const ulong *u_ptr, uint *k_ptr)
{
return proc_uint_u2k_conv_uop(u_ptr, k_ptr, NULL);
}
static int do_proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,
const struct ctl_table *tbl)
{
return proc_uint_conv(u_ptr, k_ptr, dir, tbl, false,
proc_uint_u2k_conv, proc_uint_k2u_conv);
}
static int do_proc_uint_conv_minmax(ulong *u_ptr, uint *k_ptr, int dir,
const struct ctl_table *tbl)
{
return proc_uint_conv(u_ptr, k_ptr, dir, tbl, true,
proc_uint_u2k_conv, proc_uint_k2u_conv);
}
static SYSCTL_USER_TO_KERN_INT_CONV(, SYSCTL_CONV_IDENTITY)
static SYSCTL_KERN_TO_USER_INT_CONV(, SYSCTL_CONV_IDENTITY)
@ -362,22 +466,6 @@ static SYSCTL_INT_CONV_CUSTOM(, sysctl_user_to_kern_int_conv,
static SYSCTL_INT_CONV_CUSTOM(_minmax, sysctl_user_to_kern_int_conv,
sysctl_kern_to_user_int_conv, true)
static SYSCTL_USER_TO_KERN_UINT_CONV(, SYSCTL_CONV_IDENTITY)
int sysctl_kern_to_user_uint_conv(unsigned long *u_ptr,
const unsigned int *k_ptr)
{
unsigned int val = READ_ONCE(*k_ptr);
*u_ptr = (unsigned long)val;
return 0;
}
static SYSCTL_UINT_CONV_CUSTOM(, sysctl_user_to_kern_uint_conv,
sysctl_kern_to_user_uint_conv, false)
static SYSCTL_UINT_CONV_CUSTOM(_minmax, sysctl_user_to_kern_uint_conv,
sysctl_kern_to_user_uint_conv, true)
static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
static int do_proc_dointvec(const struct ctl_table *table, int dir,
@ -576,7 +664,6 @@ int proc_douintvec_conv(const struct ctl_table *table, int dir, void *buffer,
return do_proc_douintvec(table, dir, buffer, lenp, ppos, conv);
}
/**
* proc_dobool - read/write a bool
* @table: the sysctl table
@ -1079,6 +1166,25 @@ int proc_douintvec_conv(const struct ctl_table *table, int write, void *buffer,
return -ENOSYS;
}
int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr)
{
return -ENOSYS;
}
int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr,
ulong (*u_ptr_op)(const ulong))
{
return -ENOSYS;
}
int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,
const struct ctl_table *tbl, bool k_ptr_range_check,
int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr),
int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr))
{
return -ENOSYS;
}
int proc_dou8vec_minmax(const struct ctl_table *table, int dir,
void *buffer, size_t *lenp, loff_t *ppos)
{