diff mbox series

[RFC] Remove bdflush syscall stub

Message ID 20190528101012.11402-1-chrubis@suse.cz (mailing list archive)
State Awaiting Upstream
Headers show
Series [RFC] Remove bdflush syscall stub | expand

Commit Message

Cyril Hrubis May 28, 2019, 10:10 a.m. UTC
While reviewing LTP testcases I've found that we still carry workaround
for 17 years old distributions that attempted to start bdflush from
userspace. I guess it's about the time to remove it.

I've tested the patch on i386. Before the patch calling bdflush() with
attempt to tune a variable returned 0 and after the patch the syscall
fails with EINVAL. You can use the now deleted LTP bdflush testcase for
testing:

https://github.com/linux-test-project/ltp/commit/53ede74305ff7f6498d7456b6e3ea3053ed4b7dd

Also I'm not 100% sure that I patched all the syscall tables correctly,
so this needs a proper review from arch maintainers.

CC: linux-alpha@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
CC: linux-ia64@vger.kernel.org
CC: linux-m68k@lists.linux-m68k.org
CC: Michal Simek <monstr@monstr.eu>
CC: linux-mips@vger.kernel.org
CC: linux-parisc@vger.kernel.org
CC: linuxppc-dev@lists.ozlabs.org
CC: linux-s390@vger.kernel.org
CC: linux-sh@vger.kernel.org
CC: sparclinux@vger.kernel.org
CC: linux-xtensa@linux-xtensa.org
CC: linux-fsdevel@vger.kernel.org
CC: linux-api@vger.kernel.org
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
---
 arch/alpha/kernel/syscalls/syscall.tbl        |  2 +-
 arch/arm/tools/syscall.tbl                    |  2 +-
 arch/arm64/include/asm/unistd32.h             |  3 +--
 arch/ia64/kernel/syscalls/syscall.tbl         |  2 +-
 arch/m68k/kernel/syscalls/syscall.tbl         |  2 +-
 arch/microblaze/kernel/syscalls/syscall.tbl   |  2 +-
 arch/mips/kernel/syscalls/syscall_o32.tbl     |  2 +-
 arch/parisc/kernel/syscalls/syscall.tbl       |  2 +-
 arch/powerpc/kernel/syscalls/syscall.tbl      |  2 +-
 arch/s390/kernel/syscalls/syscall.tbl         |  2 +-
 arch/sh/include/uapi/asm/unistd_64.h          |  2 +-
 arch/sh/kernel/syscalls/syscall.tbl           |  2 +-
 arch/sh/kernel/syscalls_64.S                  |  2 +-
 arch/sparc/kernel/syscalls/syscall.tbl        |  2 +-
 arch/x86/entry/syscalls/syscall_32.tbl        |  2 +-
 arch/xtensa/kernel/syscalls/syscall.tbl       |  2 +-
 fs/buffer.c                                   | 27 -------------------
 include/linux/syscalls.h                      |  1 -
 kernel/sys_ni.c                               |  1 -
 .../arch/powerpc/entry/syscalls/syscall.tbl   |  2 +-
 .../perf/arch/s390/entry/syscalls/syscall.tbl |  2 +-
 21 files changed, 18 insertions(+), 48 deletions(-)

Comments

Andreas Schwab May 28, 2019, 10:25 a.m. UTC | #1
On Mai 28 2019, Cyril Hrubis <chrubis@suse.cz> wrote:

> I've tested the patch on i386. Before the patch calling bdflush() with
> attempt to tune a variable returned 0 and after the patch the syscall
> fails with EINVAL.

Should be ENOSYS, doesn't it?

Andreas.
Cyril Hrubis May 28, 2019, 10:40 a.m. UTC | #2
Hi!
> > I've tested the patch on i386. Before the patch calling bdflush() with
> > attempt to tune a variable returned 0 and after the patch the syscall
> > fails with EINVAL.
> 
> Should be ENOSYS, doesn't it?

My bad, the LTP syscall wrapper handles ENOSYS and produces skipped
results based on that.

EINVAL is what you get for not yet implemented syscalls, i.e. new
syscall on old kernel.
Florian Weimer May 28, 2019, 11:03 a.m. UTC | #3
* Cyril Hrubis:

> Hi!
>> > I've tested the patch on i386. Before the patch calling bdflush() with
>> > attempt to tune a variable returned 0 and after the patch the syscall
>> > fails with EINVAL.
>> 
>> Should be ENOSYS, doesn't it?
>
> My bad, the LTP syscall wrapper handles ENOSYS and produces skipped
> results based on that.
>
> EINVAL is what you get for not yet implemented syscalls, i.e. new
> syscall on old kernel.

EINVAL?  Is that a bdflush-specific thing, test-specific, or is itmore
general?

glibc has fallback paths that test for ENOSYS only.  EINVAL will be
passed to the application, skipping fallback.  For missing system calls,
this is not what we want.

Thanks,
Florian
Cyril Hrubis May 28, 2019, 11:20 a.m. UTC | #4
Hi!
> >> > I've tested the patch on i386. Before the patch calling bdflush() with
> >> > attempt to tune a variable returned 0 and after the patch the syscall
> >> > fails with EINVAL.
> >> 
> >> Should be ENOSYS, doesn't it?
> >
> > My bad, the LTP syscall wrapper handles ENOSYS and produces skipped
> > results based on that.
> >
> > EINVAL is what you get for not yet implemented syscalls, i.e. new
> > syscall on old kernel.
> 
> EINVAL?  Is that a bdflush-specific thing, test-specific, or is itmore
> general?
> 
> glibc has fallback paths that test for ENOSYS only.  EINVAL will be
> passed to the application, skipping fallback.  For missing system calls,
> this is not what we want.

The syscall returns ENOSYS after this change, sorry for the confusion.
diff mbox series

Patch

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 9e7704e44f6d..3a08a2708a8a 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -230,7 +230,7 @@ 
 259	common	osf_swapctl			sys_ni_syscall
 260	common	osf_memcntl			sys_ni_syscall
 261	common	osf_fdatasync			sys_ni_syscall
-300	common	bdflush				sys_bdflush
+# 300 was sys_bdflush
 301	common	sethae				sys_sethae
 302	common	mount				sys_mount
 303	common	old_adjtimex			sys_old_adjtimex
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index aaf479a9e92d..3f247c627b5f 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -147,7 +147,7 @@ 
 131	common	quotactl		sys_quotactl
 132	common	getpgid			sys_getpgid
 133	common	fchdir			sys_fchdir
-134	common	bdflush			sys_bdflush
+# 134 was sys_bdflush
 135	common	sysfs			sys_sysfs
 136	common	personality		sys_personality
 # 137 was sys_afs_syscall
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index c39e90600bb3..fd23e4db9d76 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -289,8 +289,7 @@  __SYSCALL(__NR_quotactl, sys_quotactl)
 __SYSCALL(__NR_getpgid, sys_getpgid)
 #define __NR_fchdir 133
 __SYSCALL(__NR_fchdir, sys_fchdir)
-#define __NR_bdflush 134
-__SYSCALL(__NR_bdflush, sys_bdflush)
+			/* 134 was sys_bdflush */
 #define __NR_sysfs 135
 __SYSCALL(__NR_sysfs, sys_sysfs)
 #define __NR_personality 136
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index e01df3f2f80d..9cd63d82de53 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -123,7 +123,7 @@ 
 # 1135 was get_kernel_syms
 # 1136 was query_module
 113	common	quotactl			sys_quotactl
-114	common	bdflush				sys_bdflush
+# 114 was bdflush
 115	common	sysfs				sys_sysfs
 116	common	personality			sys_personality
 117	common	afs_syscall			sys_ni_syscall
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 7e3d0734b2f3..0c44ee777964 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -141,7 +141,7 @@ 
 131	common	quotactl			sys_quotactl
 132	common	getpgid				sys_getpgid
 133	common	fchdir				sys_fchdir
-134	common	bdflush				sys_bdflush
+# 134 was bdflush
 135	common	sysfs				sys_sysfs
 136	common	personality			sys_personality
 # 137 was afs_syscall
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 26339e417695..1f1288d6212d 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -141,7 +141,7 @@ 
 131	common	quotactl			sys_quotactl
 132	common	getpgid				sys_getpgid
 133	common	fchdir				sys_fchdir
-134	common	bdflush				sys_bdflush
+# 134 was bdflush
 135	common	sysfs				sys_sysfs
 136	common	personality			sys_personality
 137	common	afs_syscall			sys_ni_syscall
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 3cc1374e02d0..537a3828b9a0 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -145,7 +145,7 @@ 
 131	o32	quotactl			sys_quotactl
 132	o32	getpgid				sys_getpgid
 133	o32	fchdir				sys_fchdir
-134	o32	bdflush				sys_bdflush
+# 134 was sys_bdflush
 135	o32	sysfs				sys_sysfs
 136	o32	personality			sys_personality			sys_32_personality
 137	o32	afs_syscall			sys_ni_syscall
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index c9e377d59232..3ab53f3ed358 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -147,7 +147,7 @@ 
 131	common	quotactl		sys_quotactl
 132	common	getpgid			sys_getpgid
 133	common	fchdir			sys_fchdir
-134	common	bdflush			sys_bdflush
+# 134 was sys_bdflush
 135	common	sysfs			sys_sysfs
 136	32	personality		parisc_personality
 136	64	personality		sys_personality
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 103655d84b4b..5ce016e6122c 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -176,7 +176,7 @@ 
 131	nospu	quotactl			sys_quotactl
 132	common	getpgid				sys_getpgid
 133	common	fchdir				sys_fchdir
-134	common	bdflush				sys_bdflush
+# 134 was bdflush
 135	common	sysfs				sys_sysfs
 136	32	personality			sys_personality			ppc64_personality
 136	64	personality			ppc64_personality
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index e822b2964a83..3364da213530 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -122,7 +122,7 @@ 
 131  common	quotactl		sys_quotactl			sys_quotactl
 132  common	getpgid			sys_getpgid			sys_getpgid
 133  common	fchdir			sys_fchdir			sys_fchdir
-134  common	bdflush			sys_bdflush			sys_bdflush
+# 134 was bdflush
 135  common	sysfs			sys_sysfs			sys_sysfs
 136  common	personality		sys_s390_personality		sys_s390_personality
 137  common	afs_syscall		-				-
diff --git a/arch/sh/include/uapi/asm/unistd_64.h b/arch/sh/include/uapi/asm/unistd_64.h
index 75da54851f02..5bd0f0c29a95 100644
--- a/arch/sh/include/uapi/asm/unistd_64.h
+++ b/arch/sh/include/uapi/asm/unistd_64.h
@@ -149,7 +149,7 @@ 
 #define __NR_quotactl		131
 #define __NR_getpgid		132
 #define __NR_fchdir		133
-#define __NR_bdflush		134
+				/* 134 was sys_bdflush */
 #define __NR_sysfs		135
 #define __NR_personality	136
 				/* 137 was sys_afs_syscall */
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 016a727d4357..328edef02905 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -141,7 +141,7 @@ 
 131	common	quotactl			sys_quotactl
 132	common	getpgid				sys_getpgid
 133	common	fchdir				sys_fchdir
-134	common	bdflush				sys_bdflush
+# 134 was bdflush
 135	common	sysfs				sys_sysfs
 136	common	personality			sys_personality
 # 137 was afs_syscall
diff --git a/arch/sh/kernel/syscalls_64.S b/arch/sh/kernel/syscalls_64.S
index 1bcb86f0b728..1b7ad08f5d2f 100644
--- a/arch/sh/kernel/syscalls_64.S
+++ b/arch/sh/kernel/syscalls_64.S
@@ -151,7 +151,7 @@  sys_call_table:
 	.long sys_quotactl
 	.long sys_getpgid
 	.long sys_fchdir
-	.long sys_bdflush
+	.long sys_ni_syscall		/* 134 old bdflush */
 	.long sys_sysfs			/* 135 */
 	.long sys_personality
 	.long sys_ni_syscall	/* for afs_syscall */
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index e047480b1605..e199062c38c7 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -270,7 +270,7 @@ 
 222	common	delete_module		sys_delete_module
 223	common	get_kernel_syms		sys_ni_syscall
 224	common	getpgid			sys_getpgid
-225	common	bdflush			sys_bdflush
+225	common	bdflush			sys_ni_syscall
 226	common	sysfs			sys_sysfs
 227	common	afs_syscall		sys_nis_syscall
 228	common	setfsuid		sys_setfsuid16
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index ad968b7bac72..b699144d52fc 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -145,7 +145,7 @@ 
 131	i386	quotactl		sys_quotactl			__ia32_compat_sys_quotactl32
 132	i386	getpgid			sys_getpgid			__ia32_sys_getpgid
 133	i386	fchdir			sys_fchdir			__ia32_sys_fchdir
-134	i386	bdflush			sys_bdflush			__ia32_sys_bdflush
+134	i386	bdflush			sys_ni_syscall			sys_ni_syscall
 135	i386	sysfs			sys_sysfs			__ia32_sys_sysfs
 136	i386	personality		sys_personality			__ia32_sys_personality
 137	i386	afs_syscall
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 5fa0ee1c8e00..6b9fdddd7994 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -223,7 +223,7 @@ 
 # 205 was old nfsservctl
 205	common	nfsservctl			sys_ni_syscall
 206	common	_sysctl				sys_sysctl
-207	common	bdflush				sys_bdflush
+207	common	bdflush				sys_ni_syscall
 208	common	uname				sys_newuname
 209	common	sysinfo				sys_sysinfo
 210	common	init_module			sys_init_module
diff --git a/fs/buffer.c b/fs/buffer.c
index e450c55f6434..6f052ada051c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3307,33 +3307,6 @@  int try_to_free_buffers(struct page *page)
 }
 EXPORT_SYMBOL(try_to_free_buffers);
 
-/*
- * There are no bdflush tunables left.  But distributions are
- * still running obsolete flush daemons, so we terminate them here.
- *
- * Use of bdflush() is deprecated and will be removed in a future kernel.
- * The `flush-X' kernel threads fully replace bdflush daemons and this call.
- */
-SYSCALL_DEFINE2(bdflush, int, func, long, data)
-{
-	static int msg_count;
-
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
-
-	if (msg_count < 5) {
-		msg_count++;
-		printk(KERN_INFO
-			"warning: process `%s' used the obsolete bdflush"
-			" system call\n", current->comm);
-		printk(KERN_INFO "Fix your initscripts?\n");
-	}
-
-	if (func == 1)
-		do_exit(0);
-	return 0;
-}
-
 /*
  * Buffer-head allocation
  */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e2870fe1be5b..3ede2f17a044 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1104,7 +1104,6 @@  asmlinkage long sys_ustat(unsigned dev, struct ustat __user *ubuf);
 asmlinkage long sys_vfork(void);
 asmlinkage long sys_recv(int, void __user *, size_t, unsigned);
 asmlinkage long sys_send(int, void __user *, size_t, unsigned);
-asmlinkage long sys_bdflush(int func, long data);
 asmlinkage long sys_oldumount(char __user *name);
 asmlinkage long sys_uselib(const char __user *library);
 asmlinkage long sys_sysctl(struct __sysctl_args __user *args);
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 4d9ae5ea6caf..5bab44795a17 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -405,7 +405,6 @@  COND_SYSCALL(epoll_wait);
 COND_SYSCALL(recv);
 COND_SYSCALL_COMPAT(recv);
 COND_SYSCALL(send);
-COND_SYSCALL(bdflush);
 COND_SYSCALL(uselib);
 
 
diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
index db3bbb8744af..56b5567de7ff 100644
--- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
@@ -169,7 +169,7 @@ 
 131	nospu	quotactl			sys_quotactl
 132	common	getpgid				sys_getpgid
 133	common	fchdir				sys_fchdir
-134	common	bdflush				sys_bdflush
+134	common	bdflush				sys_ni_syscall
 135	common	sysfs				sys_sysfs
 136	32	personality			sys_personality			ppc64_personality
 136	64	personality			ppc64_personality
diff --git a/tools/perf/arch/s390/entry/syscalls/syscall.tbl b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
index b38d48464368..a83eba11c877 100644
--- a/tools/perf/arch/s390/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/s390/entry/syscalls/syscall.tbl
@@ -122,7 +122,7 @@ 
 131  common	quotactl		sys_quotactl			compat_sys_quotactl
 132  common	getpgid			sys_getpgid			sys_getpgid
 133  common	fchdir			sys_fchdir			sys_fchdir
-134  common	bdflush			sys_bdflush			compat_sys_bdflush
+134  common	bdflush			-				-
 135  common	sysfs			sys_sysfs			compat_sys_sysfs
 136  common	personality		sys_s390_personality		sys_s390_personality
 137  common	afs_syscall		-				-