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| author | Dominik Brodowski <linux@dominikbrodowski.net> | 2018-03-11 13:34:40 +0300 |
|---|---|---|
| committer | Dominik Brodowski <linux@dominikbrodowski.net> | 2018-04-02 21:15:49 +0300 |
| commit | c7248321a3d42ffba78db0dde88d1c49ca1c045f (patch) | |
| tree | ecd2b86a077f764e200b3c214cd1f851d4e3c6e0 /fs/file.c | |
| parent | 3a18ef5c1b3935cb05888fc37964321f7bd6231d (diff) | |
| download | linux-c7248321a3d42ffba78db0dde88d1c49ca1c045f.tar.xz | |
fs: add ksys_dup{,3}() helper; remove in-kernel calls to sys_dup{,3}()
Using ksys_dup() and ksys_dup3() as helper functions allows us to
avoid the in-kernel calls to the sys_dup() and sys_dup3() syscalls.
The ksys_ prefix denotes that these functions are meant as a drop-in
replacement for the syscalls. In particular, they use the same
calling convention as sys_dup{,3}().
In the near future, the fs-external callers of ksys_dup{,3}() should be
converted to call do_dup2() directly. Then, ksys_dup{,3}() can be moved
within sys_dup{,3}() again.
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: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Diffstat (limited to 'fs/file.c')
| -rw-r--r-- | fs/file.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/file.c b/fs/file.c index 42f0db4bd0fb..d304004f0b65 100644 --- a/fs/file.c +++ b/fs/file.c @@ -870,7 +870,7 @@ out_unlock: return err; } -SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) +static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags) { int err = -EBADF; struct file *file; @@ -904,6 +904,11 @@ out_unlock: return err; } +SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) +{ + return ksys_dup3(oldfd, newfd, flags); +} + SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) { if (unlikely(newfd == oldfd)) { /* corner case */ @@ -916,10 +921,10 @@ SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) rcu_read_unlock(); return retval; } - return sys_dup3(oldfd, newfd, 0); + return ksys_dup3(oldfd, newfd, 0); } -SYSCALL_DEFINE1(dup, unsigned int, fildes) +int ksys_dup(unsigned int fildes) { int ret = -EBADF; struct file *file = fget_raw(fildes); @@ -934,6 +939,11 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes) return ret; } +SYSCALL_DEFINE1(dup, unsigned int, fildes) +{ + return ksys_dup(fildes); +} + int f_dupfd(unsigned int from, struct file *file, unsigned flags) { int err; |