From c7b95d5156a9ee70f800bd2e47a9eba677be73e1 Mon Sep 17 00:00:00 2001 From: Dominik Brodowski Date: Mon, 19 Mar 2018 17:51:36 +0100 Subject: [PATCH] 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 Cc: linux-mm@kvack.org Signed-off-by: Dominik Brodowski --- arch/mips/kernel/linux32.c | 2 +- arch/parisc/kernel/sys_parisc.c | 2 +- arch/powerpc/kernel/sys_ppc32.c | 2 +- arch/s390/kernel/compat_linux.c | 2 +- arch/sparc/kernel/sys_sparc32.c | 2 +- arch/x86/ia32/sys_ia32.c | 2 +- include/linux/syscalls.h | 1 + mm/readahead.c | 7 ++++++- 8 files changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c index 0571ab7b68b0..318f1c05c5b3 100644 --- a/arch/mips/kernel/linux32.c +++ b/arch/mips/kernel/linux32.c @@ -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, diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c index 080d566654ea..8c99ebbe2bac 100644 --- a/arch/parisc/kernel/sys_parisc.c +++ b/arch/parisc/kernel/sys_parisc.c @@ -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, diff --git a/arch/powerpc/kernel/sys_ppc32.c b/arch/powerpc/kernel/sys_ppc32.c index 0b95fa13307f..c11c73373691 100644 --- a/arch/powerpc/kernel/sys_ppc32.c +++ b/arch/powerpc/kernel/sys_ppc32.c @@ -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, diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c index da5ef7718254..8ac38d51ed7d 100644 --- a/arch/s390/kernel/compat_linux.c +++ b/arch/s390/kernel/compat_linux.c @@ -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 { diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c index 4da66aed50b4..f166e5bbf506 100644 --- a/arch/sparc/kernel/sys_sparc32.c +++ b/arch/sparc/kernel/sys_sparc32.c @@ -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, diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c index bff71b9ae3f5..bd8a7020b9a7 100644 --- a/arch/x86/ia32/sys_ia32.c +++ b/arch/x86/ia32/sys_ia32.c @@ -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, diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index ec866c959e7d..815fbdd9cca1 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -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 diff --git a/mm/readahead.c b/mm/readahead.c index c4ca70239233..4d57b4644f98 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -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); +}