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fs: add ksys_p{read,write}64() helpers; remove in-kernel calls to syscalls 

Using the ksys_p{read,write}64() wrappers allows us to get rid of
in-kernel calls to the sys_pread64() and sys_pwrite64() syscalls.
The ksys_ prefix denotes that this function is meant as a drop-in
replacement for the syscall. In particular, it uses the same calling
convention as sys_p{read,write}64().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-19 17:38:31 +01:00
parent df260e21e6
commit 36028d5dd7
9 changed files with 36 additions and 20 deletions
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4
arch/mips/kernel/linux32.c
View File

@ -105,13 +105,13 @@ SYSCALL_DEFINE5(32_llseek, unsigned int, fd, unsigned int, offset_high,
SYSCALL_DEFINE6(32_pread, unsigned long, fd, char __user *, buf, size_t, count,
unsigned long, unused, unsigned long, a4, unsigned long, a5)
{
return sys_pread64(fd, buf, count, merge_64(a4, a5));
return ksys_pread64(fd, buf, count, merge_64(a4, a5));
}
SYSCALL_DEFINE6(32_pwrite, unsigned int, fd, const char __user *, buf,
size_t, count, u32, unused, u64, a4, u64, a5)
{
return sys_pwrite64(fd, buf, count, merge_64(a4, a5));
return ksys_pwrite64(fd, buf, count, merge_64(a4, a5));
}
SYSCALL_DEFINE1(32_personality, unsigned long, personality)

4
arch/parisc/kernel/sys_parisc.c
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@ -333,13 +333,13 @@ asmlinkage long parisc_ftruncate64(unsigned int fd,
asmlinkage ssize_t parisc_pread64(unsigned int fd, char __user *buf, size_t count,
unsigned int high, unsigned int low)
{
return sys_pread64(fd, buf, count, (loff_t)high << 32 | low);
return ksys_pread64(fd, buf, count, (loff_t)high << 32 | low);
}
asmlinkage ssize_t parisc_pwrite64(unsigned int fd, const char __user *buf,
size_t count, unsigned int high, unsigned int low)
{
return sys_pwrite64(fd, buf, count, (loff_t)high << 32 | low);
return ksys_pwrite64(fd, buf, count, (loff_t)high << 32 | low);
}
asmlinkage ssize_t parisc_readahead(int fd, unsigned int high, unsigned int low,

4
arch/powerpc/kernel/sys_ppc32.c
View File

@ -77,13 +77,13 @@ unsigned long compat_sys_mmap2(unsigned long addr, size_t len,
compat_ssize_t compat_sys_pread64(unsigned int fd, char __user *ubuf, compat_size_t count,
u32 reg6, u32 poshi, u32 poslo)
{
return sys_pread64(fd, ubuf, count, ((loff_t)poshi << 32) | poslo);
return ksys_pread64(fd, ubuf, count, ((loff_t)poshi << 32) | poslo);
}
compat_ssize_t compat_sys_pwrite64(unsigned int fd, const char __user *ubuf, compat_size_t count,
u32 reg6, u32 poshi, u32 poslo)
{
return sys_pwrite64(fd, ubuf, count, ((loff_t)poshi << 32) | poslo);
return ksys_pwrite64(fd, ubuf, count, ((loff_t)poshi << 32) | poslo);
}
compat_ssize_t compat_sys_readahead(int fd, u32 r4, u32 offhi, u32 offlo, u32 count)

4
arch/s390/kernel/compat_linux.c
View File

@ -315,7 +315,7 @@ COMPAT_SYSCALL_DEFINE5(s390_pread64, unsigned int, fd, char __user *, ubuf,
{
if ((compat_ssize_t) count < 0)
return -EINVAL;
return sys_pread64(fd, ubuf, count, (unsigned long)high << 32 | low);
return ksys_pread64(fd, ubuf, count, (unsigned long)high << 32 | low);
}
COMPAT_SYSCALL_DEFINE5(s390_pwrite64, unsigned int, fd, const char __user *, ubuf,
@ -323,7 +323,7 @@ COMPAT_SYSCALL_DEFINE5(s390_pwrite64, unsigned int, fd, const char __user *, ubu
{
if ((compat_ssize_t) count < 0)
return -EINVAL;
return sys_pwrite64(fd, ubuf, count, (unsigned long)high << 32 | low);
return ksys_pwrite64(fd, ubuf, count, (unsigned long)high << 32 | low);
}
COMPAT_SYSCALL_DEFINE4(s390_readahead, int, fd, u32, high, u32, low, s32, count)

4
arch/sh/kernel/sys_sh32.c
View File

@ -39,13 +39,13 @@ asmlinkage int sys_sh_pipe(void)
asmlinkage ssize_t sys_pread_wrapper(unsigned int fd, char __user *buf,
size_t count, long dummy, loff_t pos)
{
return sys_pread64(fd, buf, count, pos);
return ksys_pread64(fd, buf, count, pos);
}
asmlinkage ssize_t sys_pwrite_wrapper(unsigned int fd, const char __user *buf,
size_t count, long dummy, loff_t pos)
{
return sys_pwrite64(fd, buf, count, pos);
return ksys_pwrite64(fd, buf, count, pos);
}
asmlinkage int sys_fadvise64_64_wrapper(int fd, u32 offset0, u32 offset1,

4
arch/sparc/kernel/sys_sparc32.c
View File

@ -200,7 +200,7 @@ asmlinkage compat_ssize_t sys32_pread64(unsigned int fd,
unsigned long poshi,
unsigned long poslo)
{
return sys_pread64(fd, ubuf, count, (poshi << 32) | poslo);
return ksys_pread64(fd, ubuf, count, (poshi << 32) | poslo);
}
asmlinkage compat_ssize_t sys32_pwrite64(unsigned int fd,
@ -209,7 +209,7 @@ asmlinkage compat_ssize_t sys32_pwrite64(unsigned int fd,
unsigned long poshi,
unsigned long poslo)
{
return sys_pwrite64(fd, ubuf, count, (poshi << 32) | poslo);
return ksys_pwrite64(fd, ubuf, count, (poshi << 32) | poslo);
}
asmlinkage long compat_sys_readahead(int fd,

8
arch/x86/ia32/sys_ia32.c
View File

@ -174,15 +174,15 @@ COMPAT_SYSCALL_DEFINE1(x86_mmap, struct mmap_arg_struct32 __user *, arg)
COMPAT_SYSCALL_DEFINE5(x86_pread, unsigned int, fd, char __user *, ubuf,
u32, count, u32, poslo, u32, poshi)
{
return sys_pread64(fd, ubuf, count,
((loff_t)AA(poshi) << 32) | AA(poslo));
return ksys_pread64(fd, ubuf, count,
((loff_t)AA(poshi) << 32) | AA(poslo));
}
COMPAT_SYSCALL_DEFINE5(x86_pwrite, unsigned int, fd, const char __user *, ubuf,
u32, count, u32, poslo, u32, poshi)
{
return sys_pwrite64(fd, ubuf, count,
((loff_t)AA(poshi) << 32) | AA(poslo));
return ksys_pwrite64(fd, ubuf, count,
((loff_t)AA(poshi) << 32) | AA(poslo));
}

20
fs/read_write.c
View File

@ -610,8 +610,8 @@ SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
return ksys_write(fd, buf, count);
}
SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
size_t, count, loff_t, pos)
ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count,
loff_t pos)
{
struct fd f;
ssize_t ret = -EBADF;
@ -630,8 +630,14 @@ SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
return ret;
}
SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
size_t, count, loff_t, pos)
SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
size_t, count, loff_t, pos)
{
return ksys_pread64(fd, buf, count, pos);
}
ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf,
size_t count, loff_t pos)
{
struct fd f;
ssize_t ret = -EBADF;
@ -650,6 +656,12 @@ SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
return ret;
}
SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
size_t, count, loff_t, pos)
{
return ksys_pwrite64(fd, buf, count, pos);
}
static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
loff_t *ppos, int type, rwf_t flags)
{

4
include/linux/syscalls.h
View File

@ -965,6 +965,10 @@ int ksys_unshare(unsigned long unshare_flags);
int ksys_setsid(void);
int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
unsigned int flags);
ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count,
loff_t pos);
ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf,
size_t count, loff_t pos);
/*
* The following kernel syscall equivalents are just wrappers to fs-internal