[PATCH 3/6] fs/splice: support compiling out splice-family syscalls
Many embedded systems will not need the splice-family syscalls (splice, vmsplice, tee and sendfile). Omitting them saves space. This adds a new EXPERT config option CONFIG_SYSCALL_SPLICE (default y) to support compiling them out. The goal is to completely compile out fs/splice. To achieve this, the remaining patch-set will deal with fs/splice exports. As far as possible, the impact on other device drivers will be minimized so as to reduce the maintenance burden of CONFIG_SYSCALL_SPLICE. The use of exported functions will be solved by transparently mocking them out with static inlines. Use of the exported pipe_buf_operations struct however require direct modification in fs/fuse and net/core. The next two patches will deal with this. Once all exports are solved, fs/splice can be compiled out. The bloat benefit of this patch given a tinyconfig is: add/remove: 0/16 grow/shrink: 2/5 up/down: 114/-3693 (-3579) function old new delta splice_direct_to_actor 348 416 +68 splice_to_pipe 371 417 +46 splice_from_pipe_next107 106 -1 fdput 11 - -11 signal_pending39 26 -13 fdget 56 42 -14 user_page_pipe_buf_ops20 - -20 user_page_pipe_buf_steal 25 - -25 file_end_write58 29 -29 file_start_write 68 34 -34 pipe_to_user 43 - -43 wakeup_pipe_readers 54 - -54 do_splice_to 87 - -87 ipipe_prep.part 92 - -92 opipe_prep.part 119 --119 sys_sendfile 122 --122 sys_sendfile64 126 --126 sys_vmsplice 137 --137 vmsplice_to_user 205 --205 sys_tee 491 --491 do_sendfile 492 --492 vmsplice_to_pipe 558 --558 sys_splice 1020 - -1020 Signed-off-by: Pieter Smith --- fs/splice.c | 2 ++ init/Kconfig| 10 ++ kernel/sys_ni.c | 8 3 files changed, 20 insertions(+) diff --git a/fs/splice.c b/fs/splice.c index 44b201b..7c4c695 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1316,6 +1316,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, return ret; } +#ifdef CONFIG_SYSCALL_SPLICE static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, struct pipe_inode_info *opipe, size_t len, unsigned int flags); @@ -2200,4 +2201,5 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, return do_sendfile(out_fd, in_fd, NULL, count, 0); } #endif +#endif diff --git a/init/Kconfig b/init/Kconfig index d811d5f..dec9819 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1571,6 +1571,16 @@ config NTP system clock to an NTP server, you can disable this option to save space. +config SYSCALL_SPLICE + bool "Enable splice/vmsplice/tee/sendfile syscalls" if EXPERT + default y + help + This option enables the splice, vmsplice, tee and sendfile syscalls. These + are used by applications to: move data between buffers and arbitrary file + descriptors; "copy" data between buffers; or copy data from userspace into + buffers. If building an embedded system where no applications use these + syscalls, you can disable this option to save space. + config PCI_QUIRKS default y bool "Enable PCI quirk workarounds" if EXPERT diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index d2f5b00..25d5551 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -170,6 +170,14 @@ cond_syscall(sys_fstat); cond_syscall(sys_stat); cond_syscall(sys_uname); cond_syscall(sys_olduname); +cond_syscall(sys_vmsplice); +cond_syscall(sys_splice); +cond_syscall(sys_tee); +cond_syscall(sys_sendfile); +cond_syscall(sys_sendfile64); +cond_syscall(compat_sys_vmsplice); +cond_syscall(compat_sys_sendfile); +cond_syscall(compat_sys_sendfile64); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3/6] fs/splice: support compiling out splice-family syscalls
On Sat, Nov 22, 2014 at 09:59:58PM +0100, Pieter Smith wrote: > Many embedded systems will not need the splice-family syscalls (splice, > vmsplice, tee and sendfile). Omitting them saves space. This adds a new > EXPERT > config option CONFIG_SYSCALL_SPLICE (default y) to support compiling them out. > > This patch removes almost all callers of .splice_read() and .splice_write() > in the file_operations struct. This paves the way to eventually compile out > the > .splice_read and .splice_write members of the file_operations struct as well > as > the remaining splice-related infrastructure. This commit message doesn't reflect the new approach of leaving those members in the structure. The patch looks good otherwise. - Josh Triplett > add/remove: 0/16 grow/shrink: 2/5 up/down: 114/-3693 (-3579) > function old new delta > splice_direct_to_actor 348 416 +68 > splice_to_pipe 371 417 +46 > splice_from_pipe_next107 106 -1 > fdput 11 - -11 > signal_pending39 26 -13 > fdget 56 42 -14 > user_page_pipe_buf_ops20 - -20 > user_page_pipe_buf_steal 25 - -25 > file_end_write58 29 -29 > file_start_write 68 34 -34 > pipe_to_user 43 - -43 > wakeup_pipe_readers 54 - -54 > do_splice_to 87 - -87 > ipipe_prep.part 92 - -92 > opipe_prep.part 119 --119 > sys_sendfile 122 --122 > sys_sendfile64 126 --126 > sys_vmsplice 137 --137 > vmsplice_to_user 205 --205 > sys_tee 491 --491 > do_sendfile 492 --492 > vmsplice_to_pipe 558 --558 > sys_splice 1020 - -1020 > > Signed-off-by: Pieter Smith > --- > fs/splice.c | 2 ++ > init/Kconfig| 10 ++ > kernel/sys_ni.c | 8 > 3 files changed, 20 insertions(+) > > diff --git a/fs/splice.c b/fs/splice.c > index 44b201b..7c4c695 100644 > --- a/fs/splice.c > +++ b/fs/splice.c > @@ -1316,6 +1316,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, > struct file *out, > return ret; > } > > +#ifdef CONFIG_SYSCALL_SPLICE > static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, > struct pipe_inode_info *opipe, > size_t len, unsigned int flags); > @@ -2200,4 +2201,5 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, > in_fd, > return do_sendfile(out_fd, in_fd, NULL, count, 0); > } > #endif > +#endif > > diff --git a/init/Kconfig b/init/Kconfig > index d811d5f..dec9819 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1571,6 +1571,16 @@ config NTP > system clock to an NTP server, you can disable this option to save > space. > > +config SYSCALL_SPLICE > + bool "Enable splice/vmsplice/tee/sendfile syscalls" if EXPERT > + default y > + help > + This option enables the splice, vmsplice, tee and sendfile syscalls. > These > + are used by applications to: move data between buffers and arbitrary > file > + descriptors; "copy" data between buffers; or copy data from userspace > into > + buffers. If building an embedded system where no applications use > these > + syscalls, you can disable this option to save space. > + > config PCI_QUIRKS > default y > bool "Enable PCI quirk workarounds" if EXPERT > diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c > index d2f5b00..25d5551 100644 > --- a/kernel/sys_ni.c > +++ b/kernel/sys_ni.c > @@ -170,6 +170,14 @@ cond_syscall(sys_fstat); > cond_syscall(sys_stat); > cond_syscall(sys_uname); > cond_syscall(sys_olduname); > +cond_syscall(sys_vmsplice); > +cond_syscall(sys_splice); > +cond_syscall(sys_tee); > +cond_syscall(sys_sendfile); > +cond_syscall(sys_sendfile64); > +cond_syscall(compat_sys_vmsplice); > +cond_syscall(compat_sys_sendfile); > +cond_syscall(compat_sys_sendfile64); > > /* arch-specific weak syscall entries */ > cond_syscall(sys_pciconfig_read); > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH 3/6] fs/splice: support compiling out splice-family syscalls
Many embedded systems will not need the splice-family syscalls (splice, vmsplice, tee and sendfile). Omitting them saves space. This adds a new EXPERT config option CONFIG_SYSCALL_SPLICE (default y) to support compiling them out. This patch removes almost all callers of .splice_read() and .splice_write() in the file_operations struct. This paves the way to eventually compile out the .splice_read and .splice_write members of the file_operations struct as well as the remaining splice-related infrastructure. add/remove: 0/16 grow/shrink: 2/5 up/down: 114/-3693 (-3579) function old new delta splice_direct_to_actor 348 416 +68 splice_to_pipe 371 417 +46 splice_from_pipe_next107 106 -1 fdput 11 - -11 signal_pending39 26 -13 fdget 56 42 -14 user_page_pipe_buf_ops20 - -20 user_page_pipe_buf_steal 25 - -25 file_end_write58 29 -29 file_start_write 68 34 -34 pipe_to_user 43 - -43 wakeup_pipe_readers 54 - -54 do_splice_to 87 - -87 ipipe_prep.part 92 - -92 opipe_prep.part 119 --119 sys_sendfile 122 --122 sys_sendfile64 126 --126 sys_vmsplice 137 --137 vmsplice_to_user 205 --205 sys_tee 491 --491 do_sendfile 492 --492 vmsplice_to_pipe 558 --558 sys_splice 1020 - -1020 Signed-off-by: Pieter Smith --- fs/splice.c | 2 ++ init/Kconfig| 10 ++ kernel/sys_ni.c | 8 3 files changed, 20 insertions(+) diff --git a/fs/splice.c b/fs/splice.c index 44b201b..7c4c695 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1316,6 +1316,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, return ret; } +#ifdef CONFIG_SYSCALL_SPLICE static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, struct pipe_inode_info *opipe, size_t len, unsigned int flags); @@ -2200,4 +2201,5 @@ COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, return do_sendfile(out_fd, in_fd, NULL, count, 0); } #endif +#endif diff --git a/init/Kconfig b/init/Kconfig index d811d5f..dec9819 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1571,6 +1571,16 @@ config NTP system clock to an NTP server, you can disable this option to save space. +config SYSCALL_SPLICE + bool "Enable splice/vmsplice/tee/sendfile syscalls" if EXPERT + default y + help + This option enables the splice, vmsplice, tee and sendfile syscalls. These + are used by applications to: move data between buffers and arbitrary file + descriptors; "copy" data between buffers; or copy data from userspace into + buffers. If building an embedded system where no applications use these + syscalls, you can disable this option to save space. + config PCI_QUIRKS default y bool "Enable PCI quirk workarounds" if EXPERT diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index d2f5b00..25d5551 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -170,6 +170,14 @@ cond_syscall(sys_fstat); cond_syscall(sys_stat); cond_syscall(sys_uname); cond_syscall(sys_olduname); +cond_syscall(sys_vmsplice); +cond_syscall(sys_splice); +cond_syscall(sys_tee); +cond_syscall(sys_sendfile); +cond_syscall(sys_sendfile64); +cond_syscall(compat_sys_vmsplice); +cond_syscall(compat_sys_sendfile); +cond_syscall(compat_sys_sendfile64); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
