Re: [git pull] vfs.git part 3

From: Christoph Hellwig
Date: Thu Jul 06 2017 - 12:58:44 EST


On Thu, Jul 06, 2017 at 04:51:13PM +0100, Al Viro wrote:
> On Thu, Jul 06, 2017 at 04:46:02PM +0100, Al Viro wrote:
>
> > That - on #work.read_write, as in vfs.git at the moment...
>
> ... and for COMPAT_SYSCALL you need
> #define __SC_DELOUSE(t,v) ((__force t)(unsigned long)(v))
> in linux/compat.h

I'm still getting warnings with both these force casts. This is
the current stack:


diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
index 0ddd37e6c29d..019f0de892c3 100644
--- a/arch/s390/include/asm/compat.h
+++ b/arch/s390/include/asm/compat.h
@@ -12,7 +12,7 @@

#define __SC_DELOUSE(t,v) ({ \
BUILD_BUG_ON(sizeof(t) > 4 && !__TYPE_IS_PTR(t)); \
- (t)(__TYPE_IS_PTR(t) ? ((v) & 0x7fffffff) : (v)); \
+ (__force t)(__TYPE_IS_PTR(t) ? ((v) & 0x7fffffff) : (v)); \
})

#define PSW32_MASK_PER 0x40000000UL
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 38d0383dc7f9..bc69d40c4e8b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -969,7 +969,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
int use_wgather;
loff_t pos = offset;
unsigned int pflags = current->flags;
- int flags = 0;
+ rwf_t flags = 0;

if (test_bit(RQ_LOCAL, &rqstp->rq_flags))
/*
diff --git a/fs/read_write.c b/fs/read_write.c
index a2cbc8303dae..bc2db5e5cd19 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -633,7 +633,7 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
EXPORT_SYMBOL(iov_shorten);

static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
- loff_t *ppos, int type, int flags)
+ loff_t *ppos, int type, rwf_t flags)
{
struct kiocb kiocb;
ssize_t ret;
@@ -655,7 +655,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,

/* Do it by hand, with file-ops */
static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
- loff_t *ppos, int type, int flags)
+ loff_t *ppos, int type, rwf_t flags)
{
ssize_t ret = 0;

@@ -871,7 +871,7 @@ ssize_t compat_rw_copy_check_uvector(int type,
#endif

static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
- loff_t *pos, int flags)
+ loff_t *pos, rwf_t flags)
{
size_t tot_len;
ssize_t ret = 0;
@@ -899,7 +899,7 @@ static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
}

ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
- int flags)
+ rwf_t flags)
{
if (!file->f_op->read_iter)
return -EINVAL;
@@ -908,7 +908,7 @@ ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
EXPORT_SYMBOL(vfs_iter_read);

static ssize_t do_iter_write(struct file *file, struct iov_iter *iter,
- loff_t *pos, int flags)
+ loff_t *pos, rwf_t flags)
{
size_t tot_len;
ssize_t ret = 0;
@@ -937,7 +937,7 @@ static ssize_t do_iter_write(struct file *file, struct iov_iter *iter,
}

ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
- int flags)
+ rwf_t flags)
{
if (!file->f_op->write_iter)
return -EINVAL;
@@ -946,7 +946,7 @@ ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
EXPORT_SYMBOL(vfs_iter_write);

ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
- unsigned long vlen, loff_t *pos, int flags)
+ unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
@@ -964,7 +964,7 @@ ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
EXPORT_SYMBOL(vfs_readv);

ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
- unsigned long vlen, loff_t *pos, int flags)
+ unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
@@ -981,7 +981,7 @@ ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
EXPORT_SYMBOL(vfs_writev);

static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, int flags)
+ unsigned long vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
@@ -1001,7 +1001,7 @@ static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
}

static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, int flags)
+ unsigned long vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
@@ -1027,7 +1027,7 @@ static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
}

static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, loff_t pos, int flags)
+ unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret = -EBADF;
@@ -1050,7 +1050,7 @@ static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,
}

static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec,
- unsigned long vlen, loff_t pos, int flags)
+ unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret = -EBADF;
@@ -1094,7 +1094,7 @@ SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,

SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
- int, flags)
+ rwf_t, flags)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);

@@ -1114,7 +1114,7 @@ SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,

SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
- int, flags)
+ rwf_t, flags)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);

@@ -1127,7 +1127,7 @@ SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
#ifdef CONFIG_COMPAT
static size_t compat_readv(struct file *file,
const struct compat_iovec __user *vec,
- unsigned long vlen, loff_t *pos, int flags)
+ unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
@@ -1147,7 +1147,7 @@ static size_t compat_readv(struct file *file,

static size_t do_compat_readv(compat_ulong_t fd,
const struct compat_iovec __user *vec,
- compat_ulong_t vlen, int flags)
+ compat_ulong_t vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret;
@@ -1173,7 +1173,7 @@ COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,

static long do_compat_preadv64(unsigned long fd,
const struct compat_iovec __user *vec,
- unsigned long vlen, loff_t pos, int flags)
+ unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret;
@@ -1211,7 +1211,7 @@ COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2
COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
const struct compat_iovec __user *,vec,
- unsigned long, vlen, loff_t, pos, int, flags)
+ unsigned long, vlen, loff_t, pos, rwf_t, flags)
{
return do_compat_preadv64(fd, vec, vlen, pos, flags);
}
@@ -1220,7 +1220,7 @@ COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high,
- int, flags)
+ rwf_t, flags)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;

@@ -1232,7 +1232,7 @@ COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd,

static size_t compat_writev(struct file *file,
const struct compat_iovec __user *vec,
- unsigned long vlen, loff_t *pos, int flags)
+ unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
@@ -1252,7 +1252,7 @@ static size_t compat_writev(struct file *file,

static size_t do_compat_writev(compat_ulong_t fd,
const struct compat_iovec __user* vec,
- compat_ulong_t vlen, int flags)
+ compat_ulong_t vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret;
@@ -1277,7 +1277,7 @@ COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,

static long do_compat_pwritev64(unsigned long fd,
const struct compat_iovec __user *vec,
- unsigned long vlen, loff_t pos, int flags)
+ unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret;
@@ -1315,7 +1315,7 @@ COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2
COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
const struct compat_iovec __user *,vec,
- unsigned long, vlen, loff_t, pos, int, flags)
+ unsigned long, vlen, loff_t, pos, rwf_t, flags)
{
return do_compat_pwritev64(fd, vec, vlen, pos, flags);
}
@@ -1323,7 +1323,7 @@ COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,

COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
- compat_ulong_t, vlen, u32, pos_low, u32, pos_high, int, flags)
+ compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 2ed54020ace0..09a975f4102f 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -27,7 +27,7 @@
#endif

#ifndef __SC_DELOUSE
-#define __SC_DELOUSE(t,v) ((t)(unsigned long)(v))
+#define __SC_DELOUSE(t,v) ((__force t)(unsigned long)(v))
#endif

#define COMPAT_SYSCALL_DEFINE0(name) \
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9380c40b498b..1f217331dae6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -70,6 +70,8 @@ extern int leases_enable, lease_break_time;
extern int sysctl_protected_symlinks;
extern int sysctl_protected_hardlinks;

+typedef __kernel_rwf_t rwf_t;
+
struct buffer_head;
typedef int (get_block_t)(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
@@ -1764,9 +1766,9 @@ extern ssize_t __vfs_write(struct file *, const char __user *, size_t, loff_t *)
extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
- unsigned long, loff_t *, int);
+ unsigned long, loff_t *, rwf_t);
extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
- unsigned long, loff_t *, int);
+ unsigned long, loff_t *, rwf_t);
extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,
loff_t, size_t, unsigned int);
extern int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
@@ -2820,9 +2822,9 @@ extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);

ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
- int flags);
+ rwf_t flags);
ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
- int flags);
+ rwf_t flags);

/* fs/block_dev.c */
extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
@@ -3088,7 +3090,7 @@ static inline int iocb_flags(struct file *file)
return res;
}

-static inline int kiocb_set_rw_flags(struct kiocb *ki, int flags)
+static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
{
if (unlikely(flags & ~RWF_SUPPORTED))
return -EOPNOTSUPP;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 980c3c9b06f8..1a78dbc6c900 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -104,7 +104,7 @@ union bpf_attr;
#define __TYPE_IS_UL(t) (__same_type((t)0, 0UL))
#define __TYPE_IS_LL(t) (__same_type((t)0, 0LL) || __same_type((t)0, 0ULL))
#define __SC_LONG(t, a) __typeof(__builtin_choose_expr(__TYPE_IS_LL(t), 0LL, 0L)) a
-#define __SC_CAST(t, a) (t) a
+#define __SC_CAST(t, a) (__force t) a
#define __SC_ARGS(t, a) a
#define __SC_TEST(t, a) (void)BUILD_BUG_ON_ZERO(!__TYPE_IS_LL(t) && sizeof(t) > sizeof(long))

diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h
index a2d4a8ac94ca..a04adbc70ddf 100644
--- a/include/uapi/linux/aio_abi.h
+++ b/include/uapi/linux/aio_abi.h
@@ -28,6 +28,7 @@
#define __LINUX__AIO_ABI_H

#include <linux/types.h>
+#include <linux/fs.h>
#include <asm/byteorder.h>

typedef __kernel_ulong_t aio_context_t;
@@ -62,14 +63,6 @@ struct io_event {
__s64 res2; /* secondary result */
};

-#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
-#define PADDED(x,y) x, y
-#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
-#define PADDED(x,y) y, x
-#else
-#error edit for your odd byteorder.
-#endif
-
/*
* we always use a 64bit off_t when communicating
* with userland. its up to libraries to do the
@@ -79,8 +72,16 @@ struct io_event {
struct iocb {
/* these are internal to the kernel/libc. */
__u64 aio_data; /* data to be returned in event's data */
- __u32 PADDED(aio_key, aio_rw_flags);
- /* the kernel sets aio_key to the req # */
+
+#if defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
+ __u32 aio_key; /* the kernel sets aio_key to the req # */
+ __kernel_rwf_t aio_rw_flags; /* RWF_* flags */
+#elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
+ __kernel_rwf_t aio_rw_flags; /* RWF_* flags */
+ __u32 aio_key; /* the kernel sets aio_key to the req # */
+#else
+#error edit for your odd byteorder.
+#endif

/* common fields */
__u16 aio_lio_opcode; /* see IOCB_CMD_ above */
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 27d8c36c04af..e8ebc18aa9c9 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -356,13 +356,25 @@ struct fscrypt_key {
#define SYNC_FILE_RANGE_WRITE 2
#define SYNC_FILE_RANGE_WAIT_AFTER 4

-/* flags for preadv2/pwritev2: */
-#define RWF_HIPRI 0x00000001 /* high priority request, poll if possible */
-#define RWF_DSYNC 0x00000002 /* per-IO O_DSYNC */
-#define RWF_SYNC 0x00000004 /* per-IO O_SYNC */
-#define RWF_NOWAIT 0x00000008 /* per-IO, return -EAGAIN if operation would block */
-
-#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC |\
- RWF_NOWAIT)
+/*
+ * Flags for preadv2/pwritev2:
+ */
+
+typedef int __bitwise __kernel_rwf_t;
+
+/* high priority request, poll if possible */
+#define RWF_HIPRI ((__force __kernel_rwf_t)0x00000001)
+
+/* per-IO O_DSYNC */
+#define RWF_DSYNC ((__force __kernel_rwf_t)0x00000002)
+
+/* per-IO O_SYNC */
+#define RWF_SYNC ((__force __kernel_rwf_t)0x00000004)
+
+/* per-IO, return -EAGAIN if operation would block */
+#define RWF_NOWAIT ((__force __kernel_rwf_t)0x00000008)
+
+/* mask of flags supported by the kernel */
+#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT)

#endif /* _UAPI_LINUX_FS_H */