[PATCH v6 3/7] 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 along with the syscalls. 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 overal maintenance burden of CONFIG_SYSCALL_SPLICE. The use of exported functions will be solved by transparently mocking them out with static inlines. Uses 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. The last change required before fs/splice can be comipled out is making fs/nfsd aware of the lacking splice support in file-systems when CONFIG_SYSCALL_SPLICE is undefined. 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
[PATCH v6 3/7] 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 along with the syscalls. 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 overal maintenance burden of CONFIG_SYSCALL_SPLICE. The use of exported functions will be solved by transparently mocking them out with static inlines. Uses 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. The last change required before fs/splice can be comipled out is making fs/nfsd aware of the lacking splice support in file-systems when CONFIG_SYSCALL_SPLICE is undefined. 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 pie...@boesman.nl --- 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
