[CFT][PATCH] exit/bdflush: Remove the deprecated bdflush system call

Eric W. Biederman
2021-06-29T20:28:27Z

The bdflush system call has been deprecated for a very long time.
Recently Michael Schmitz tested[1] and found that the last known
caller of of the bdflush system call is unaffected by it's removal.

Since the code is not needed delete it.

[1] https://lkml.kernel.org/r/36123b5d-daa0-6c2b-f2d4-a942f069fd54@gmail.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---

I think we have consensus that bdflush can be removed. Can folks please
verify I have removed it correctly?

Michael could you give me a Tested-by on this patch?

arch/alpha/kernel/syscalls/syscall.tbl | 2 +-
arch/arm/tools/syscall.tbl | 2 +-
arch/arm64/include/asm/unistd32.h | 2 +-
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/kernel/syscalls/syscall.tbl | 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 -
include/uapi/linux/capability.h | 1 -
kernel/sys_ni.c | 1 -
.../arch/powerpc/entry/syscalls/syscall.tbl | 2 +-
.../perf/arch/s390/entry/syscalls/syscall.tbl | 2 +-
20 files changed, 16 insertions(+), 46 deletions(-)

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 3000a2e8ee21..85d2bcd9cf36 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 common bdflush sys_ni_syscall
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 28e03b5fec00..241988512648 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 common bdflush sys_ni_syscall
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 5dab69d2c22b..a35cd6c4909c 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -279,7 +279,7 @@ __SYSCALL(__NR_getpgid, sys_getpgid)
#define __NR_fchdir 133
__SYSCALL(__NR_fchdir, sys_fchdir)
#define __NR_bdflush 134
-__SYSCALL(__NR_bdflush, sys_bdflush)
+__SYSCALL(__NR_bdflush, sys_ni_syscall)
#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 bb11fe4c875a..7de53a9a2972 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 common bdflush sys_ni_syscall
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 79c2d24c89dd..be5abd9c8c07 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 common bdflush sys_ni_syscall
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 b11395a20c20..555fd987f4ab 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 common bdflush sys_ni_syscall
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 d560c467a8c6..2c6b10db3bd5 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 o32 bdflush sys_ni_syscall
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 aabc37f8cae3..51c156cb00f1 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 common bdflush sys_ni_syscall
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 8f052ff4058c..2518e4e6dccf 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 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/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 0690263df1dd..ffcf03714f12 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 common bdflush sys_ni_syscall sys_ni_syscall
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/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 0b91499ebdcf..6e7305066a70 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 common bdflush sys_ni_syscall
135 common sysfs sys_sysfs
136 common personality sys_personality
# 137 was afs_syscall
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index e34cc30ef22c..bf330dda7c61 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 4bbc267fb36b..a21a72763d58 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
132 i386 getpgid sys_getpgid
133 i386 fchdir sys_fchdir
-134 i386 bdflush sys_bdflush
+134 i386 bdflush sys_ni_syscall
135 i386 sysfs sys_sysfs
136 i386 personality sys_personality
137 i386 afs_syscall
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index fd2f30227d96..db4e3d09b249 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_ni_syscall
-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 ea48c01fb76b..04ddff76c860 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3292,33 +3292,6 @@ 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 050511e8f1f8..1bd6e05ea116 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1157,7 +1157,6 @@ 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_sysfs(int option,
diff --git a/include/uapi/linux/capability.h b/include/uapi/linux/capability.h
index 2ddb4226cd23..463d1ba2232a 100644
--- a/include/uapi/linux/capability.h
+++ b/include/uapi/linux/capability.h
@@ -243,7 +243,6 @@ struct vfs_ns_cap_data {
/* Allow examination and configuration of disk quotas */
/* Allow setting the domainname */
/* Allow setting the hostname */
-/* Allow calling bdflush() */
/* Allow mount() and umount(), setting up new smb connection */
/* Allow some autofs root ioctls */
/* Allow nfsservctl */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 0ea8128468c3..adf4d66ffae2 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -414,7 +414,6 @@ COND_SYSCALL(epoll_wait);
COND_SYSCALL(recv);
COND_SYSCALL_COMPAT(recv);
COND_SYSCALL(send);
-COND_SYSCALL(bdflush);
COND_SYSCALL(uselib);

/* optional: time32 */
diff --git a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl b/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
index 2e68fbb57cc6..ab72dec9dadb 100644
--- a/tools/perf/arch/powerpc/entry/syscalls/syscall.tbl
+++ b/tools/perf/arch/powerpc/entry/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 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 7e4a2aba366d..f2eba775e676 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 sys_quotactl
132 common getpgid sys_getpgid sys_getpgid
133 common fchdir sys_fchdir sys_fchdir
-134 common bdflush sys_bdflush sys_bdflush
+134 common bdflush - -
135 common sysfs sys_sysfs sys_sysfs
136 common personality sys_s390_personality sys_s390_personality
137 common afs_syscall - -
--
2.20.1