mm: add ksys_readahead() helper; remove in-kernel calls to sys_readahead()

Using this helper allows us to avoid the in-kernel calls to the
sys_readahead() syscall. 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_readahead().

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: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
This commit is contained in:
Dominik Brodowski 2018-03-19 17:51:36 +01:00
parent a90f590a1b
commit c7b95d5156
8 changed files with 13 additions and 7 deletions

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@ -131,7 +131,7 @@ SYSCALL_DEFINE1(32_personality, unsigned long, personality)
asmlinkage ssize_t sys32_readahead(int fd, u32 pad0, u64 a2, u64 a3,
size_t count)
{
return sys_readahead(fd, merge_64(a2, a3), count);
return ksys_readahead(fd, merge_64(a2, a3), count);
}
asmlinkage long sys32_sync_file_range(int fd, int __pad,

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@ -345,7 +345,7 @@ asmlinkage ssize_t parisc_pwrite64(unsigned int fd, const char __user *buf,
asmlinkage ssize_t parisc_readahead(int fd, unsigned int high, unsigned int low,
size_t count)
{
return sys_readahead(fd, (loff_t)high << 32 | low, count);
return ksys_readahead(fd, (loff_t)high << 32 | low, count);
}
asmlinkage long parisc_fadvise64_64(int fd,

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@ -88,7 +88,7 @@ compat_ssize_t compat_sys_pwrite64(unsigned int fd, const char __user *ubuf, com
compat_ssize_t compat_sys_readahead(int fd, u32 r4, u32 offhi, u32 offlo, u32 count)
{
return sys_readahead(fd, ((loff_t)offhi << 32) | offlo, count);
return ksys_readahead(fd, ((loff_t)offhi << 32) | offlo, count);
}
asmlinkage int compat_sys_truncate64(const char __user * path, u32 reg4,

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@ -328,7 +328,7 @@ COMPAT_SYSCALL_DEFINE5(s390_pwrite64, unsigned int, fd, const char __user *, ubu
COMPAT_SYSCALL_DEFINE4(s390_readahead, int, fd, u32, high, u32, low, s32, count)
{
return sys_readahead(fd, (unsigned long)high << 32 | low, count);
return ksys_readahead(fd, (unsigned long)high << 32 | low, count);
}
struct stat64_emu31 {

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@ -217,7 +217,7 @@ asmlinkage long compat_sys_readahead(int fd,
unsigned long offlo,
compat_size_t count)
{
return sys_readahead(fd, (offhi << 32) | offlo, count);
return ksys_readahead(fd, (offhi << 32) | offlo, count);
}
long compat_sys_fadvise64(int fd,

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@ -203,7 +203,7 @@ COMPAT_SYSCALL_DEFINE6(x86_fadvise64_64, int, fd, __u32, offset_low,
COMPAT_SYSCALL_DEFINE4(x86_readahead, int, fd, unsigned int, off_lo,
unsigned int, off_hi, size_t, count)
{
return sys_readahead(fd, ((u64)off_hi << 32) | off_lo, count);
return ksys_readahead(fd, ((u64)off_hi << 32) | off_lo, count);
}
COMPAT_SYSCALL_DEFINE6(x86_sync_file_range, int, fd, unsigned int, off_low,

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@ -982,6 +982,7 @@ static inline int ksys_fadvise64_64(int fd, loff_t offset, loff_t len,
unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags,
unsigned long fd, unsigned long pgoff);
ssize_t ksys_readahead(int fd, loff_t offset, size_t count);
/*
* The following kernel syscall equivalents are just wrappers to fs-internal

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@ -573,7 +573,7 @@ do_readahead(struct address_space *mapping, struct file *filp,
return force_page_cache_readahead(mapping, filp, index, nr);
}
SYSCALL_DEFINE3(readahead, int, fd, loff_t, offset, size_t, count)
ssize_t ksys_readahead(int fd, loff_t offset, size_t count)
{
ssize_t ret;
struct fd f;
@ -592,3 +592,8 @@ SYSCALL_DEFINE3(readahead, int, fd, loff_t, offset, size_t, count)
}
return ret;
}
SYSCALL_DEFINE3(readahead, int, fd, loff_t, offset, size_t, count)
{
return ksys_readahead(fd, offset, count);
}