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    SubjectRe: [PATCH v6 2/7] vfs: Define new syscalls preadv2,pwritev2
    Date
    Milosz Tanski <milosz@adfin.com> writes:

    > New syscalls that take an flag argument. This change does not add any specific
    > flags.

    Looks good.

    Reviewed-by: Jeff Moyer <jmoyer@redhat.com>

    >
    > Signed-off-by: Milosz Tanski <milosz@adfin.com>
    > Reviewed-by: Christoph Hellwig <hch@lst.de>
    > ---
    > fs/read_write.c | 172 ++++++++++++++++++++++++++++++--------
    > include/linux/compat.h | 6 ++
    > include/linux/syscalls.h | 6 ++
    > include/uapi/asm-generic/unistd.h | 6 +-
    > mm/filemap.c | 5 +-
    > 5 files changed, 156 insertions(+), 39 deletions(-)
    >
    > diff --git a/fs/read_write.c b/fs/read_write.c
    > index 94b2d34..b1b4bc8 100644
    > --- a/fs/read_write.c
    > +++ b/fs/read_write.c
    > @@ -866,6 +866,8 @@ ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
    > return -EBADF;
    > if (!(file->f_mode & FMODE_CAN_READ))
    > return -EINVAL;
    > + if (flags & ~0)
    > + return -EINVAL;
    >
    > return do_readv_writev(READ, file, vec, vlen, pos, flags);
    > }
    > @@ -879,21 +881,23 @@ ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
    > return -EBADF;
    > if (!(file->f_mode & FMODE_CAN_WRITE))
    > return -EINVAL;
    > + if (flags & ~0)
    > + return -EINVAL;
    >
    > return do_readv_writev(WRITE, file, vec, vlen, pos, flags);
    > }
    >
    > EXPORT_SYMBOL(vfs_writev);
    >
    > -SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
    > - unsigned long, vlen)
    > +static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
    > + unsigned long vlen, int flags)
    > {
    > struct fd f = fdget_pos(fd);
    > ssize_t ret = -EBADF;
    >
    > if (f.file) {
    > loff_t pos = file_pos_read(f.file);
    > - ret = vfs_readv(f.file, vec, vlen, &pos, 0);
    > + ret = vfs_readv(f.file, vec, vlen, &pos, flags);
    > if (ret >= 0)
    > file_pos_write(f.file, pos);
    > fdput_pos(f);
    > @@ -905,15 +909,15 @@ SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
    > return ret;
    > }
    >
    > -SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
    > - unsigned long, vlen)
    > +static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
    > + unsigned long vlen, int flags)
    > {
    > struct fd f = fdget_pos(fd);
    > ssize_t ret = -EBADF;
    >
    > if (f.file) {
    > loff_t pos = file_pos_read(f.file);
    > - ret = vfs_writev(f.file, vec, vlen, &pos, 0);
    > + ret = vfs_writev(f.file, vec, vlen, &pos, flags);
    > if (ret >= 0)
    > file_pos_write(f.file, pos);
    > fdput_pos(f);
    > @@ -931,10 +935,9 @@ static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
    > return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
    > }
    >
    > -SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
    > - unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
    > +static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,
    > + unsigned long vlen, loff_t pos, int flags)
    > {
    > - loff_t pos = pos_from_hilo(pos_h, pos_l);
    > struct fd f;
    > ssize_t ret = -EBADF;
    >
    > @@ -945,7 +948,7 @@ SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
    > if (f.file) {
    > ret = -ESPIPE;
    > if (f.file->f_mode & FMODE_PREAD)
    > - ret = vfs_readv(f.file, vec, vlen, &pos, 0);
    > + ret = vfs_readv(f.file, vec, vlen, &pos, flags);
    > fdput(f);
    > }
    >
    > @@ -955,10 +958,9 @@ SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
    > return ret;
    > }
    >
    > -SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
    > - unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
    > +static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec,
    > + unsigned long vlen, loff_t pos, int flags)
    > {
    > - loff_t pos = pos_from_hilo(pos_h, pos_l);
    > struct fd f;
    > ssize_t ret = -EBADF;
    >
    > @@ -969,7 +971,7 @@ SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
    > if (f.file) {
    > ret = -ESPIPE;
    > if (f.file->f_mode & FMODE_PWRITE)
    > - ret = vfs_writev(f.file, vec, vlen, &pos, 0);
    > + ret = vfs_writev(f.file, vec, vlen, &pos, flags);
    > fdput(f);
    > }
    >
    > @@ -979,11 +981,63 @@ SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
    > return ret;
    > }
    >
    > +SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
    > + unsigned long, vlen)
    > +{
    > + return do_readv(fd, vec, vlen, 0);
    > +}
    > +
    > +SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
    > + unsigned long, vlen)
    > +{
    > + return do_writev(fd, vec, vlen, 0);
    > +}
    > +
    > +SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
    > + unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
    > +{
    > + loff_t pos = pos_from_hilo(pos_h, pos_l);
    > +
    > + return do_preadv(fd, vec, vlen, pos, 0);
    > +}
    > +
    > +SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec,
    > + unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
    > + int, flags)
    > +{
    > + loff_t pos = pos_from_hilo(pos_h, pos_l);
    > +
    > + if (pos == -1)
    > + return do_readv(fd, vec, vlen, flags);
    > +
    > + return do_preadv(fd, vec, vlen, pos, flags);
    > +}
    > +
    > +SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
    > + unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
    > +{
    > + loff_t pos = pos_from_hilo(pos_h, pos_l);
    > +
    > + return do_pwritev(fd, vec, vlen, pos, 0);
    > +}
    > +
    > +SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
    > + unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
    > + int, flags)
    > +{
    > + loff_t pos = pos_from_hilo(pos_h, pos_l);
    > +
    > + if (pos == -1)
    > + return do_writev(fd, vec, vlen, flags);
    > +
    > + return do_pwritev(fd, vec, vlen, pos, flags);
    > +}
    > +
    > #ifdef CONFIG_COMPAT
    >
    > static ssize_t compat_do_readv_writev(int type, struct file *file,
    > const struct compat_iovec __user *uvector,
    > - unsigned long nr_segs, loff_t *pos)
    > + unsigned long nr_segs, loff_t *pos, int flags)
    > {
    > compat_ssize_t tot_len;
    > struct iovec iovstack[UIO_FASTIOV];
    > @@ -1017,7 +1071,7 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,
    >
    > if (iter_fn)
    > ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
    > - pos, iter_fn, 0);
    > + pos, iter_fn, flags);
    > else if (fnv)
    > ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
    > pos, fnv);
    > @@ -1041,7 +1095,7 @@ out:
    >
    > static size_t compat_readv(struct file *file,
    > const struct compat_iovec __user *vec,
    > - unsigned long vlen, loff_t *pos)
    > + unsigned long vlen, loff_t *pos, int flags)
    > {
    > ssize_t ret = -EBADF;
    >
    > @@ -1051,8 +1105,10 @@ static size_t compat_readv(struct file *file,
    > ret = -EINVAL;
    > if (!(file->f_mode & FMODE_CAN_READ))
    > goto out;
    > + if (flags & ~0)
    > + goto out;
    >
    > - ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
    > + ret = compat_do_readv_writev(READ, file, vec, vlen, pos, flags);
    >
    > out:
    > if (ret > 0)
    > @@ -1061,9 +1117,9 @@ out:
    > return ret;
    > }
    >
    > -COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
    > - const struct compat_iovec __user *,vec,
    > - compat_ulong_t, vlen)
    > +static size_t __compat_sys_readv(compat_ulong_t fd,
    > + const struct compat_iovec __user *vec,
    > + compat_ulong_t vlen, int flags)
    > {
    > struct fd f = fdget_pos(fd);
    > ssize_t ret;
    > @@ -1072,16 +1128,24 @@ COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
    > if (!f.file)
    > return -EBADF;
    > pos = f.file->f_pos;
    > - ret = compat_readv(f.file, vec, vlen, &pos);
    > + ret = compat_readv(f.file, vec, vlen, &pos, flags);
    > if (ret >= 0)
    > f.file->f_pos = pos;
    > fdput_pos(f);
    > return ret;
    > +
    > +}
    > +
    > +COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
    > + const struct compat_iovec __user *,vec,
    > + compat_ulong_t, vlen)
    > +{
    > + return __compat_sys_readv(fd, vec, vlen, 0);
    > }
    >
    > static long __compat_sys_preadv64(unsigned long fd,
    > const struct compat_iovec __user *vec,
    > - unsigned long vlen, loff_t pos)
    > + unsigned long vlen, loff_t pos, int flags)
    > {
    > struct fd f;
    > ssize_t ret;
    > @@ -1093,7 +1157,7 @@ static long __compat_sys_preadv64(unsigned long fd,
    > return -EBADF;
    > ret = -ESPIPE;
    > if (f.file->f_mode & FMODE_PREAD)
    > - ret = compat_readv(f.file, vec, vlen, &pos);
    > + ret = compat_readv(f.file, vec, vlen, &pos, flags);
    > fdput(f);
    > return ret;
    > }
    > @@ -1103,7 +1167,7 @@ COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
    > const struct compat_iovec __user *,vec,
    > unsigned long, vlen, loff_t, pos)
    > {
    > - return __compat_sys_preadv64(fd, vec, vlen, pos);
    > + return __compat_sys_preadv64(fd, vec, vlen, pos, 0);
    > }
    > #endif
    >
    > @@ -1113,12 +1177,25 @@ COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
    > {
    > loff_t pos = ((loff_t)pos_high << 32) | pos_low;
    >
    > - return __compat_sys_preadv64(fd, vec, vlen, pos);
    > + return __compat_sys_preadv64(fd, vec, vlen, pos, 0);
    > +}
    > +
    > +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)
    > +{
    > + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
    > +
    > + if (pos == -1)
    > + return __compat_sys_readv(fd, vec, vlen, flags);
    > +
    > + return __compat_sys_preadv64(fd, vec, vlen, pos, flags);
    > }
    >
    > static size_t compat_writev(struct file *file,
    > const struct compat_iovec __user *vec,
    > - unsigned long vlen, loff_t *pos)
    > + unsigned long vlen, loff_t *pos, int flags)
    > {
    > ssize_t ret = -EBADF;
    >
    > @@ -1128,8 +1205,10 @@ static size_t compat_writev(struct file *file,
    > ret = -EINVAL;
    > if (!(file->f_mode & FMODE_CAN_WRITE))
    > goto out;
    > + if (flags & ~0)
    > + goto out;
    >
    > - ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
    > + ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos, flags);
    >
    > out:
    > if (ret > 0)
    > @@ -1138,9 +1217,9 @@ out:
    > return ret;
    > }
    >
    > -COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
    > - const struct compat_iovec __user *, vec,
    > - compat_ulong_t, vlen)
    > +static size_t __compat_sys_writev(compat_ulong_t fd,
    > + const struct compat_iovec __user* vec,
    > + compat_ulong_t vlen, int flags)
    > {
    > struct fd f = fdget_pos(fd);
    > ssize_t ret;
    > @@ -1149,28 +1228,36 @@ COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
    > if (!f.file)
    > return -EBADF;
    > pos = f.file->f_pos;
    > - ret = compat_writev(f.file, vec, vlen, &pos);
    > + ret = compat_writev(f.file, vec, vlen, &pos, flags);
    > if (ret >= 0)
    > f.file->f_pos = pos;
    > fdput_pos(f);
    > return ret;
    > }
    >
    > +COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
    > + const struct compat_iovec __user *, vec,
    > + compat_ulong_t, vlen)
    > +{
    > + return __compat_sys_writev(fd, vec, vlen, 0);
    > +}
    > +
    > static long __compat_sys_pwritev64(unsigned long fd,
    > const struct compat_iovec __user *vec,
    > - unsigned long vlen, loff_t pos)
    > + unsigned long vlen, loff_t pos, int flags)
    > {
    > struct fd f;
    > ssize_t ret;
    >
    > if (pos < 0)
    > return -EINVAL;
    > +
    > f = fdget(fd);
    > if (!f.file)
    > return -EBADF;
    > ret = -ESPIPE;
    > if (f.file->f_mode & FMODE_PWRITE)
    > - ret = compat_writev(f.file, vec, vlen, &pos);
    > + ret = compat_writev(f.file, vec, vlen, &pos, flags);
    > fdput(f);
    > return ret;
    > }
    > @@ -1180,7 +1267,7 @@ COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
    > const struct compat_iovec __user *,vec,
    > unsigned long, vlen, loff_t, pos)
    > {
    > - return __compat_sys_pwritev64(fd, vec, vlen, pos);
    > + return __compat_sys_pwritev64(fd, vec, vlen, pos, 0);
    > }
    > #endif
    >
    > @@ -1190,8 +1277,21 @@ COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
    > {
    > loff_t pos = ((loff_t)pos_high << 32) | pos_low;
    >
    > - return __compat_sys_pwritev64(fd, vec, vlen, pos);
    > + return __compat_sys_pwritev64(fd, vec, vlen, pos, 0);
    > +}
    > +
    > +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)
    > +{
    > + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
    > +
    > + if (pos == -1)
    > + return __compat_sys_writev(fd, vec, vlen, flags);
    > +
    > + return __compat_sys_pwritev64(fd, vec, vlen, pos, flags);
    > }
    > +
    > #endif
    >
    > static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
    > diff --git a/include/linux/compat.h b/include/linux/compat.h
    > index e649426..63a94e2 100644
    > --- a/include/linux/compat.h
    > +++ b/include/linux/compat.h
    > @@ -340,6 +340,12 @@ asmlinkage ssize_t compat_sys_preadv(compat_ulong_t fd,
    > asmlinkage ssize_t compat_sys_pwritev(compat_ulong_t fd,
    > const struct compat_iovec __user *vec,
    > compat_ulong_t vlen, u32 pos_low, u32 pos_high);
    > +asmlinkage ssize_t compat_sys_preadv2(compat_ulong_t fd,
    > + const struct compat_iovec __user *vec,
    > + compat_ulong_t vlen, u32 pos_low, u32 pos_high, int flags);
    > +asmlinkage ssize_t compat_sys_pwritev2(compat_ulong_t fd,
    > + const struct compat_iovec __user *vec,
    > + compat_ulong_t vlen, u32 pos_low, u32 pos_high, int flags);
    >
    > #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
    > asmlinkage long compat_sys_preadv64(unsigned long fd,
    > diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
    > index bda9b81..cedc22e 100644
    > --- a/include/linux/syscalls.h
    > +++ b/include/linux/syscalls.h
    > @@ -571,8 +571,14 @@ asmlinkage long sys_pwrite64(unsigned int fd, const char __user *buf,
    > size_t count, loff_t pos);
    > asmlinkage long sys_preadv(unsigned long fd, const struct iovec __user *vec,
    > unsigned long vlen, unsigned long pos_l, unsigned long pos_h);
    > +asmlinkage long sys_preadv2(unsigned long fd, const struct iovec __user *vec,
    > + unsigned long vlen, unsigned long pos_l, unsigned long pos_h,
    > + int flags);
    > asmlinkage long sys_pwritev(unsigned long fd, const struct iovec __user *vec,
    > unsigned long vlen, unsigned long pos_l, unsigned long pos_h);
    > +asmlinkage long sys_pwritev2(unsigned long fd, const struct iovec __user *vec,
    > + unsigned long vlen, unsigned long pos_l, unsigned long pos_h,
    > + int flags);
    > asmlinkage long sys_getcwd(char __user *buf, unsigned long size);
    > asmlinkage long sys_mkdir(const char __user *pathname, umode_t mode);
    > asmlinkage long sys_chdir(const char __user *filename);
    > diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
    > index 22749c1..9406018 100644
    > --- a/include/uapi/asm-generic/unistd.h
    > +++ b/include/uapi/asm-generic/unistd.h
    > @@ -213,6 +213,10 @@ __SC_COMP(__NR_pwrite64, sys_pwrite64, compat_sys_pwrite64)
    > __SC_COMP(__NR_preadv, sys_preadv, compat_sys_preadv)
    > #define __NR_pwritev 70
    > __SC_COMP(__NR_pwritev, sys_pwritev, compat_sys_pwritev)
    > +#define __NR_preadv2 281
    > +__SC_COMP(__NR_preadv2, sys_preadv2, compat_sys_preadv2)
    > +#define __NR_pwritev2 282
    > +__SC_COMP(__NR_pwritev2, sys_pwritev2, compat_sys_pwritev2)
    >
    > /* fs/sendfile.c */
    > #define __NR3264_sendfile 71
    > @@ -709,7 +713,7 @@ __SYSCALL(__NR_memfd_create, sys_memfd_create)
    > __SYSCALL(__NR_bpf, sys_bpf)
    >
    > #undef __NR_syscalls
    > -#define __NR_syscalls 281
    > +#define __NR_syscalls 283
    >
    > /*
    > * All syscalls below here should go away really,
    > diff --git a/mm/filemap.c b/mm/filemap.c
    > index 14b4642..530c263 100644
    > --- a/mm/filemap.c
    > +++ b/mm/filemap.c
    > @@ -1457,6 +1457,7 @@ static void shrink_readahead_size_eio(struct file *filp,
    > * @ppos: current file position
    > * @iter: data destination
    > * @written: already copied
    > + * @flags: optional flags
    > *
    > * This is a generic file read routine, and uses the
    > * mapping->a_ops->readpage() function for the actual low-level stuff.
    > @@ -1465,7 +1466,7 @@ static void shrink_readahead_size_eio(struct file *filp,
    > * of the logic when it comes to error handling etc.
    > */
    > static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
    > - struct iov_iter *iter, ssize_t written)
    > + struct iov_iter *iter, ssize_t written, int flags)
    > {
    > struct address_space *mapping = filp->f_mapping;
    > struct inode *inode = mapping->host;
    > @@ -1735,7 +1736,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
    > }
    > }
    >
    > - retval = do_generic_file_read(file, ppos, iter, retval);
    > + retval = do_generic_file_read(file, ppos, iter, retval, iocb->ki_rwflags);
    > out:
    > return retval;
    > }


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