Hi folks,
Next round of the preadv & pwritev patch series. The whitespace bugs
should finally be gone now, checkpatch has nothing to complain about.
There is now a git tree with the patches (branch 'preadv'):
git://git.et.redhat.com/kernel-kraxel.git
http://git.et.redhat.com/?p=kernel-kraxel.git;a=shortlog;h=refs/heads/preadv
Plan it so get this into the linux-next once it comes back to life (after
LCA?).
As for userspace bits someone asked for:
Qemu wants use that to handle virtual disk I/O. A patch for qemu can be
found here: http://article.gmane.org/gmane.comp.emulators.qemu/36851
The code can't put into use yet though as the qemu block layer needs
some changes to pass though iovecs to the disk image format driver code.
Note this isn't the first attempt to get preadv support into the kernel,
therefore I expect others (databases?) will quickly use that too.
Also *BSD has this syscall for quite some time, thus there likely is
code using this in the wild already ...
cheers,
Gerd
Factor out some code from compat_sys_readv() which can be shared with the
upcoming compat_sys_preadv().
Signed-off-by: Gerd Hoffmann <[email protected]>
---
fs/compat.c | 26 ++++++++++++++++++--------
1 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/fs/compat.c b/fs/compat.c
index 65a070e..75c1b46 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1167,16 +1167,12 @@ out:
return ret;
}
-asmlinkage ssize_t
-compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen)
+static size_t compat_readv(struct file *file,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, loff_t *pos)
{
- struct file *file;
ssize_t ret = -EBADF;
- file = fget(fd);
- if (!file)
- return -EBADF;
-
if (!(file->f_mode & FMODE_READ))
goto out;
@@ -1184,12 +1180,26 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsign
if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
goto out;
- ret = compat_do_readv_writev(READ, file, vec, vlen, &file->f_pos);
+ ret = compat_do_readv_writev(READ, file, vec, vlen, pos);
out:
if (ret > 0)
add_rchar(current, ret);
inc_syscr(current);
+ return ret;
+}
+
+asmlinkage ssize_t
+compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec,
+ unsigned long vlen)
+{
+ struct file *file;
+ ssize_t ret;
+
+ file = fget(fd);
+ if (!file)
+ return -EBADF;
+ ret = compat_readv(file, vec, vlen, &file->f_pos);
fput(file);
return ret;
}
--
1.6.1
Factor out some code from compat_sys_writev() which can be shared with the
upcoming compat_sys_pwritev().
Signed-off-by: Gerd Hoffmann <[email protected]>
---
fs/compat.c | 25 ++++++++++++++++++-------
1 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/fs/compat.c b/fs/compat.c
index 75c1b46..4e65644 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1204,15 +1204,12 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec,
return ret;
}
-asmlinkage ssize_t
-compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen)
+static size_t compat_writev(struct file *file,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, loff_t *pos)
{
- struct file *file;
ssize_t ret = -EBADF;
- file = fget(fd);
- if (!file)
- return -EBADF;
if (!(file->f_mode & FMODE_WRITE))
goto out;
@@ -1220,12 +1217,26 @@ compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec, unsig
if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
goto out;
- ret = compat_do_readv_writev(WRITE, file, vec, vlen, &file->f_pos);
+ ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos);
out:
if (ret > 0)
add_wchar(current, ret);
inc_syscw(current);
+ return ret;
+}
+
+asmlinkage ssize_t
+compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec,
+ unsigned long vlen)
+{
+ struct file *file;
+ ssize_t ret;
+
+ file = fget(fd);
+ if (!file)
+ return -EBADF;
+ ret = compat_writev(file, vec, vlen, &file->f_pos);
fput(file);
return ret;
}
--
1.6.1
This patch adds preadv and pwritev system calls. These syscalls are a
pretty straightforward combination of pread and readv (same for write).
They are quite useful for doing vectored I/O in threaded applications.
Using lseek+readv instead opens race windows you'll have to plug with
locking.
Other systems have such system calls too, for example NetBSD, check
here: http://www.daemon-systems.org/man/preadv.2.html
The application-visible interface provided by glibc should look like
this to be compatible to the existing implementations in the *BSD family:
ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);
This prototype has one problem though: On 32bit archs is the (64bit)
offset argument unaligned, which the syscall ABI of several archs
doesn't allow to do. At least s390 needs a wrapper in glibc to handle
this. As we'll need a wrappers in glibc anyway I've decided to push
problem to glibc entriely and use a syscall prototype which works
without arch-specific wrappers inside the kernel: The offset argument
is explicitly splitted into two 32bit values.
The patch sports the actual system call implementation and the windup in
the x86 system call tables. Other archs follow as separate patches.
Signed-off-by: Gerd Hoffmann <[email protected]>
---
arch/x86/ia32/ia32entry.S | 2 +
arch/x86/include/asm/unistd_32.h | 2 +
arch/x86/include/asm/unistd_64.h | 4 +++
arch/x86/kernel/syscall_table_32.S | 2 +
fs/compat.c | 36 ++++++++++++++++++++++++++
fs/read_write.c | 50 ++++++++++++++++++++++++++++++++++++
include/linux/compat.h | 6 ++++
include/linux/syscalls.h | 4 +++
8 files changed, 106 insertions(+), 0 deletions(-)
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 256b00b..9a8501b 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -826,4 +826,6 @@ ia32_sys_call_table:
.quad sys_dup3 /* 330 */
.quad sys_pipe2
.quad sys_inotify_init1
+ .quad compat_sys_preadv
+ .quad compat_sys_pwritev
ia32_syscall_end:
diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
index f2bba78..6e72d74 100644
--- a/arch/x86/include/asm/unistd_32.h
+++ b/arch/x86/include/asm/unistd_32.h
@@ -338,6 +338,8 @@
#define __NR_dup3 330
#define __NR_pipe2 331
#define __NR_inotify_init1 332
+#define __NR_preadv 333
+#define __NR_pwritev 334
#ifdef __KERNEL__
diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
index d2e415e..f818294 100644
--- a/arch/x86/include/asm/unistd_64.h
+++ b/arch/x86/include/asm/unistd_64.h
@@ -653,6 +653,10 @@ __SYSCALL(__NR_dup3, sys_dup3)
__SYSCALL(__NR_pipe2, sys_pipe2)
#define __NR_inotify_init1 294
__SYSCALL(__NR_inotify_init1, sys_inotify_init1)
+#define __NR_preadv 295
+__SYSCALL(__NR_preadv, sys_preadv)
+#define __NR_pwritev 296
+__SYSCALL(__NR_pwritev, sys_pwritev)
#ifndef __NO_STUBS
diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
index e2e86a0..106204c 100644
--- a/arch/x86/kernel/syscall_table_32.S
+++ b/arch/x86/kernel/syscall_table_32.S
@@ -332,3 +332,5 @@ ENTRY(sys_call_table)
.long sys_dup3 /* 330 */
.long sys_pipe2
.long sys_inotify_init1
+ .long sys_preadv
+ .long sys_pwritev
diff --git a/fs/compat.c b/fs/compat.c
index 4e65644..1a67eee 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1204,6 +1204,24 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec,
return ret;
}
+asmlinkage ssize_t
+compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec,
+ unsigned long vlen, u32 pos_high, u32 pos_low)
+{
+ loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+ struct file *file;
+ ssize_t ret;
+
+ if (pos < 0)
+ return -EINVAL;
+ file = fget(fd);
+ if (!file)
+ return -EBADF;
+ ret = compat_readv(file, vec, vlen, &pos);
+ fput(file);
+ return ret;
+}
+
static size_t compat_writev(struct file *file,
const struct compat_iovec __user *vec,
unsigned long vlen, loff_t *pos)
@@ -1241,6 +1259,24 @@ compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec,
return ret;
}
+asmlinkage ssize_t
+compat_sys_pwritev(unsigned long fd, const struct compat_iovec __user *vec,
+ unsigned long vlen, u32 pos_high, u32 pos_low)
+{
+ loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+ struct file *file;
+ ssize_t ret;
+
+ if (pos < 0)
+ return -EINVAL;
+ file = fget(fd);
+ if (!file)
+ return -EBADF;
+ ret = compat_writev(file, vec, vlen, &pos);
+ fput(file);
+ return ret;
+}
+
asmlinkage long
compat_sys_vmsplice(int fd, const struct compat_iovec __user *iov32,
unsigned int nr_segs, unsigned int flags)
diff --git a/fs/read_write.c b/fs/read_write.c
index 400fe81..6d5d8ff 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -731,6 +731,56 @@ SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
return ret;
}
+SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
+ unsigned long, vlen, u32, pos_high, u32, pos_low)
+{
+ loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+ struct file *file;
+ ssize_t ret = -EBADF;
+ int fput_needed;
+
+ if (pos < 0)
+ return -EINVAL;
+
+ file = fget_light(fd, &fput_needed);
+ if (file) {
+ ret = -ESPIPE;
+ if (file->f_mode & FMODE_PREAD)
+ ret = vfs_readv(file, vec, vlen, &pos);
+ fput_light(file, fput_needed);
+ }
+
+ if (ret > 0)
+ add_rchar(current, ret);
+ inc_syscr(current);
+ return ret;
+}
+
+SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
+ unsigned long, vlen, u32, pos_high, u32, pos_low)
+{
+ loff_t pos = ((loff_t)pos_high << 32) | pos_low;
+ struct file *file;
+ ssize_t ret = -EBADF;
+ int fput_needed;
+
+ if (pos < 0)
+ return -EINVAL;
+
+ file = fget_light(fd, &fput_needed);
+ if (file) {
+ ret = -ESPIPE;
+ if (file->f_mode & FMODE_PWRITE)
+ ret = vfs_writev(file, vec, vlen, &pos);
+ fput_light(file, fput_needed);
+ }
+
+ if (ret > 0)
+ add_wchar(current, ret);
+ inc_syscw(current);
+ return ret;
+}
+
static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
size_t count, loff_t max)
{
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 3fd2194..79dba49 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -183,6 +183,12 @@ asmlinkage ssize_t compat_sys_readv(unsigned long fd,
const struct compat_iovec __user *vec, unsigned long vlen);
asmlinkage ssize_t compat_sys_writev(unsigned long fd,
const struct compat_iovec __user *vec, unsigned long vlen);
+asmlinkage ssize_t compat_sys_preadv(unsigned long fd,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, u32 pos_high, u32 pos_low);
+asmlinkage ssize_t compat_sys_pwritev(unsigned long fd,
+ const struct compat_iovec __user *vec,
+ unsigned long vlen, u32 pos_high, u32 pos_low);
int compat_do_execve(char * filename, compat_uptr_t __user *argv,
compat_uptr_t __user *envp, struct pt_regs * regs);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 16875f8..b63e93d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -456,6 +456,10 @@ asmlinkage long sys_pread64(unsigned int fd, char __user *buf,
size_t count, loff_t pos);
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, u32 pos_high, u32 pos_low);
+asmlinkage long sys_pwritev(unsigned long fd, const struct iovec __user *vec,
+ unsigned long vlen, u32 pos_high, u32 pos_low);
asmlinkage long sys_getcwd(char __user *buf, unsigned long size);
asmlinkage long sys_mkdir(const char __user *pathname, int mode);
asmlinkage long sys_chdir(const char __user *filename);
--
1.6.1
Signed-off-by: Gerd Hoffmann <[email protected]>
---
fs/compat.c | 20 ++++++++++++--------
1 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/fs/compat.c b/fs/compat.c
index 1a67eee..ad442ec 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1194,13 +1194,14 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec,
unsigned long vlen)
{
struct file *file;
+ int fput_needed;
ssize_t ret;
- file = fget(fd);
+ file = fget_light(fd, &fput_needed);
if (!file)
return -EBADF;
ret = compat_readv(file, vec, vlen, &file->f_pos);
- fput(file);
+ fput_light(file, fput_needed);
return ret;
}
@@ -1210,15 +1211,16 @@ compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec,
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
struct file *file;
+ int fput_needed;
ssize_t ret;
if (pos < 0)
return -EINVAL;
- file = fget(fd);
+ file = fget_light(fd, &fput_needed);
if (!file)
return -EBADF;
ret = compat_readv(file, vec, vlen, &pos);
- fput(file);
+ fput_light(file, fput_needed);
return ret;
}
@@ -1249,13 +1251,14 @@ compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec,
unsigned long vlen)
{
struct file *file;
+ int fput_needed;
ssize_t ret;
- file = fget(fd);
+ file = fget_light(fd, &fput_needed);
if (!file)
return -EBADF;
ret = compat_writev(file, vec, vlen, &file->f_pos);
- fput(file);
+ fput_light(file, fput_needed);
return ret;
}
@@ -1265,15 +1268,16 @@ compat_sys_pwritev(unsigned long fd, const struct compat_iovec __user *vec,
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
struct file *file;
+ int fput_needed;
ssize_t ret;
if (pos < 0)
return -EINVAL;
- file = fget(fd);
+ file = fget_light(fd, &fput_needed);
if (!file)
return -EBADF;
ret = compat_writev(file, vec, vlen, &pos);
- fput(file);
+ fput_light(file, fput_needed);
return ret;
}
--
1.6.1
From: Ralf Baechle <[email protected]>
From: Ralf Baechle <[email protected]>
Signed-off-by: Ralf Baechle <[email protected]>
Signed-off-by: Gerd Hoffmann <[email protected]>
---
arch/mips/include/asm/unistd.h | 18 ++++++++++++------
arch/mips/kernel/scall32-o32.S | 2 ++
arch/mips/kernel/scall64-64.S | 2 ++
arch/mips/kernel/scall64-n32.S | 2 ++
arch/mips/kernel/scall64-o32.S | 2 ++
5 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/arch/mips/include/asm/unistd.h b/arch/mips/include/asm/unistd.h
index a73e153..4000501 100644
--- a/arch/mips/include/asm/unistd.h
+++ b/arch/mips/include/asm/unistd.h
@@ -350,16 +350,18 @@
#define __NR_dup3 (__NR_Linux + 327)
#define __NR_pipe2 (__NR_Linux + 328)
#define __NR_inotify_init1 (__NR_Linux + 329)
+#define __NR_preadv (__NR_Linux + 330)
+#define __NR_pwritev (__NR_Linux + 331)
/*
* Offset of the last Linux o32 flavoured syscall
*/
-#define __NR_Linux_syscalls 329
+#define __NR_Linux_syscalls 331
#endif /* _MIPS_SIM == _MIPS_SIM_ABI32 */
#define __NR_O32_Linux 4000
-#define __NR_O32_Linux_syscalls 329
+#define __NR_O32_Linux_syscalls 331
#if _MIPS_SIM == _MIPS_SIM_ABI64
@@ -656,16 +658,18 @@
#define __NR_dup3 (__NR_Linux + 286)
#define __NR_pipe2 (__NR_Linux + 287)
#define __NR_inotify_init1 (__NR_Linux + 288)
+#define __NR_preadv (__NR_Linux + 289)
+#define __NR_pwritev (__NR_Linux + 290)
/*
* Offset of the last Linux 64-bit flavoured syscall
*/
-#define __NR_Linux_syscalls 288
+#define __NR_Linux_syscalls 290
#endif /* _MIPS_SIM == _MIPS_SIM_ABI64 */
#define __NR_64_Linux 5000
-#define __NR_64_Linux_syscalls 288
+#define __NR_64_Linux_syscalls 290
#if _MIPS_SIM == _MIPS_SIM_NABI32
@@ -966,16 +970,18 @@
#define __NR_dup3 (__NR_Linux + 290)
#define __NR_pipe2 (__NR_Linux + 291)
#define __NR_inotify_init1 (__NR_Linux + 292)
+#define __NR_preadv (__NR_Linux + 293)
+#define __NR_pwritev (__NR_Linux + 294)
/*
* Offset of the last N32 flavoured syscall
*/
-#define __NR_Linux_syscalls 292
+#define __NR_Linux_syscalls 294
#endif /* _MIPS_SIM == _MIPS_SIM_NABI32 */
#define __NR_N32_Linux 6000
-#define __NR_N32_Linux_syscalls 292
+#define __NR_N32_Linux_syscalls 294
#ifdef __KERNEL__
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
index 51d1ba4..0198a9c 100644
--- a/arch/mips/kernel/scall32-o32.S
+++ b/arch/mips/kernel/scall32-o32.S
@@ -650,6 +650,8 @@ einval: li v0, -ENOSYS
sys sys_dup3 3
sys sys_pipe2 2
sys sys_inotify_init1 1
+ sys sys_preadv 6 /* 4330 */
+ sys sys_pwritev 6
.endm
/* We pre-compute the number of _instruction_ bytes needed to
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index a9e1716..217e3ce 100644
--- a/arch/mips/kernel/scall64-64.S
+++ b/arch/mips/kernel/scall64-64.S
@@ -487,4 +487,6 @@ sys_call_table:
PTR sys_dup3
PTR sys_pipe2
PTR sys_inotify_init1
+ PTR sys_preadv
+ PTR sys_pwritev /* 5390 */
.size sys_call_table,.-sys_call_table
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index 30f3b63..f340963 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -413,4 +413,6 @@ EXPORT(sysn32_call_table)
PTR sys_dup3 /* 5290 */
PTR sys_pipe2
PTR sys_inotify_init1
+ PTR sys_preadv
+ PTR sys_pwritev
.size sysn32_call_table,.-sysn32_call_table
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index fefef4a..b1d281a 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -533,4 +533,6 @@ sys_call_table:
PTR sys_dup3
PTR sys_pipe2
PTR sys_inotify_init1
+ PTR compat_sys_preadv /* 4330 */
+ PTR compat_sys_pwritev
.size sys_call_table,.-sys_call_table
--
1.6.1
Gerd,
On Mon, Jan 26, 2009 at 2:26 PM, Gerd Hoffmann <[email protected]> wrote:
> This patch adds preadv and pwritev system calls. These syscalls are a
> pretty straightforward combination of pread and readv (same for write).
> They are quite useful for doing vectored I/O in threaded applications.
> Using lseek+readv instead opens race windows you'll have to plug with
> locking.
>
> Other systems have such system calls too, for example NetBSD, check
> here: http://www.daemon-systems.org/man/preadv.2.html
>
> The application-visible interface provided by glibc should look like
> this to be compatible to the existing implementations in the *BSD family:
>
> ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
> ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);
I earlier asked if you could provide some userspace example code using
this API. If there was a response, I missed it. Could you please
provide some working test using this interface.
Cheers,
Michael
> This prototype has one problem though: On 32bit archs is the (64bit)
> offset argument unaligned, which the syscall ABI of several archs
> doesn't allow to do. At least s390 needs a wrapper in glibc to handle
> this. As we'll need a wrappers in glibc anyway I've decided to push
> problem to glibc entriely and use a syscall prototype which works
> without arch-specific wrappers inside the kernel: The offset argument
> is explicitly splitted into two 32bit values.
>
> The patch sports the actual system call implementation and the windup in
> the x86 system call tables. Other archs follow as separate patches.
>
> Signed-off-by: Gerd Hoffmann <[email protected]>
> ---
> arch/x86/ia32/ia32entry.S | 2 +
> arch/x86/include/asm/unistd_32.h | 2 +
> arch/x86/include/asm/unistd_64.h | 4 +++
> arch/x86/kernel/syscall_table_32.S | 2 +
> fs/compat.c | 36 ++++++++++++++++++++++++++
> fs/read_write.c | 50 ++++++++++++++++++++++++++++++++++++
> include/linux/compat.h | 6 ++++
> include/linux/syscalls.h | 4 +++
> 8 files changed, 106 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
> index 256b00b..9a8501b 100644
> --- a/arch/x86/ia32/ia32entry.S
> +++ b/arch/x86/ia32/ia32entry.S
> @@ -826,4 +826,6 @@ ia32_sys_call_table:
> .quad sys_dup3 /* 330 */
> .quad sys_pipe2
> .quad sys_inotify_init1
> + .quad compat_sys_preadv
> + .quad compat_sys_pwritev
> ia32_syscall_end:
> diff --git a/arch/x86/include/asm/unistd_32.h b/arch/x86/include/asm/unistd_32.h
> index f2bba78..6e72d74 100644
> --- a/arch/x86/include/asm/unistd_32.h
> +++ b/arch/x86/include/asm/unistd_32.h
> @@ -338,6 +338,8 @@
> #define __NR_dup3 330
> #define __NR_pipe2 331
> #define __NR_inotify_init1 332
> +#define __NR_preadv 333
> +#define __NR_pwritev 334
>
> #ifdef __KERNEL__
>
> diff --git a/arch/x86/include/asm/unistd_64.h b/arch/x86/include/asm/unistd_64.h
> index d2e415e..f818294 100644
> --- a/arch/x86/include/asm/unistd_64.h
> +++ b/arch/x86/include/asm/unistd_64.h
> @@ -653,6 +653,10 @@ __SYSCALL(__NR_dup3, sys_dup3)
> __SYSCALL(__NR_pipe2, sys_pipe2)
> #define __NR_inotify_init1 294
> __SYSCALL(__NR_inotify_init1, sys_inotify_init1)
> +#define __NR_preadv 295
> +__SYSCALL(__NR_preadv, sys_preadv)
> +#define __NR_pwritev 296
> +__SYSCALL(__NR_pwritev, sys_pwritev)
>
>
> #ifndef __NO_STUBS
> diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S
> index e2e86a0..106204c 100644
> --- a/arch/x86/kernel/syscall_table_32.S
> +++ b/arch/x86/kernel/syscall_table_32.S
> @@ -332,3 +332,5 @@ ENTRY(sys_call_table)
> .long sys_dup3 /* 330 */
> .long sys_pipe2
> .long sys_inotify_init1
> + .long sys_preadv
> + .long sys_pwritev
> diff --git a/fs/compat.c b/fs/compat.c
> index 4e65644..1a67eee 100644
> --- a/fs/compat.c
> +++ b/fs/compat.c
> @@ -1204,6 +1204,24 @@ compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec,
> return ret;
> }
>
> +asmlinkage ssize_t
> +compat_sys_preadv(unsigned long fd, const struct compat_iovec __user *vec,
> + unsigned long vlen, u32 pos_high, u32 pos_low)
> +{
> + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
> + struct file *file;
> + ssize_t ret;
> +
> + if (pos < 0)
> + return -EINVAL;
> + file = fget(fd);
> + if (!file)
> + return -EBADF;
> + ret = compat_readv(file, vec, vlen, &pos);
> + fput(file);
> + return ret;
> +}
> +
> static size_t compat_writev(struct file *file,
> const struct compat_iovec __user *vec,
> unsigned long vlen, loff_t *pos)
> @@ -1241,6 +1259,24 @@ compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec,
> return ret;
> }
>
> +asmlinkage ssize_t
> +compat_sys_pwritev(unsigned long fd, const struct compat_iovec __user *vec,
> + unsigned long vlen, u32 pos_high, u32 pos_low)
> +{
> + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
> + struct file *file;
> + ssize_t ret;
> +
> + if (pos < 0)
> + return -EINVAL;
> + file = fget(fd);
> + if (!file)
> + return -EBADF;
> + ret = compat_writev(file, vec, vlen, &pos);
> + fput(file);
> + return ret;
> +}
> +
> asmlinkage long
> compat_sys_vmsplice(int fd, const struct compat_iovec __user *iov32,
> unsigned int nr_segs, unsigned int flags)
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 400fe81..6d5d8ff 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -731,6 +731,56 @@ SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
> return ret;
> }
>
> +SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
> + unsigned long, vlen, u32, pos_high, u32, pos_low)
> +{
> + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
> + struct file *file;
> + ssize_t ret = -EBADF;
> + int fput_needed;
> +
> + if (pos < 0)
> + return -EINVAL;
> +
> + file = fget_light(fd, &fput_needed);
> + if (file) {
> + ret = -ESPIPE;
> + if (file->f_mode & FMODE_PREAD)
> + ret = vfs_readv(file, vec, vlen, &pos);
> + fput_light(file, fput_needed);
> + }
> +
> + if (ret > 0)
> + add_rchar(current, ret);
> + inc_syscr(current);
> + return ret;
> +}
> +
> +SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
> + unsigned long, vlen, u32, pos_high, u32, pos_low)
> +{
> + loff_t pos = ((loff_t)pos_high << 32) | pos_low;
> + struct file *file;
> + ssize_t ret = -EBADF;
> + int fput_needed;
> +
> + if (pos < 0)
> + return -EINVAL;
> +
> + file = fget_light(fd, &fput_needed);
> + if (file) {
> + ret = -ESPIPE;
> + if (file->f_mode & FMODE_PWRITE)
> + ret = vfs_writev(file, vec, vlen, &pos);
> + fput_light(file, fput_needed);
> + }
> +
> + if (ret > 0)
> + add_wchar(current, ret);
> + inc_syscw(current);
> + return ret;
> +}
> +
> static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
> size_t count, loff_t max)
> {
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index 3fd2194..79dba49 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -183,6 +183,12 @@ asmlinkage ssize_t compat_sys_readv(unsigned long fd,
> const struct compat_iovec __user *vec, unsigned long vlen);
> asmlinkage ssize_t compat_sys_writev(unsigned long fd,
> const struct compat_iovec __user *vec, unsigned long vlen);
> +asmlinkage ssize_t compat_sys_preadv(unsigned long fd,
> + const struct compat_iovec __user *vec,
> + unsigned long vlen, u32 pos_high, u32 pos_low);
> +asmlinkage ssize_t compat_sys_pwritev(unsigned long fd,
> + const struct compat_iovec __user *vec,
> + unsigned long vlen, u32 pos_high, u32 pos_low);
>
> int compat_do_execve(char * filename, compat_uptr_t __user *argv,
> compat_uptr_t __user *envp, struct pt_regs * regs);
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 16875f8..b63e93d 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -456,6 +456,10 @@ asmlinkage long sys_pread64(unsigned int fd, char __user *buf,
> size_t count, loff_t pos);
> 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, u32 pos_high, u32 pos_low);
> +asmlinkage long sys_pwritev(unsigned long fd, const struct iovec __user *vec,
> + unsigned long vlen, u32 pos_high, u32 pos_low);
> asmlinkage long sys_getcwd(char __user *buf, unsigned long size);
> asmlinkage long sys_mkdir(const char __user *pathname, int mode);
> asmlinkage long sys_chdir(const char __user *filename);
> --
> 1.6.1
>
> --
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>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
git://git.kernel.org/pub/scm/docs/man-pages/man-pages.git
man-pages online: http://www.kernel.org/doc/man-pages/online_pages.html
Found a bug? http://www.kernel.org/doc/man-pages/reporting_bugs.html
Michael Kerrisk wrote:
>> The application-visible interface provided by glibc should look like
>> this to be compatible to the existing implementations in the *BSD family:
>>
>> ssize_t preadv(int d, const struct iovec *iov, int iovcnt, off_t offset);
>> ssize_t pwritev(int d, const struct iovec *iov, int iovcnt, off_t offset);
>
> I earlier asked if you could provide some userspace example code using
> this API. If there was a response, I missed it. Could you please
> provide some working test using this interface.
I had some ptrs in the patch series intro text.
Standalone test app is attached now.
cheers,
Gerd