From e4dc1b14d8dc57c3975bf69740e4f5cda6bfba09 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 16 Oct 2007 23:26:03 -0700 Subject: [PATCH] Use list_head in binfmt handling Switch single-linked binfmt formats list to usual list_head's. This leads to one-liners in register_binfmt() and unregister_binfmt(). The downside is one pointer more in struct linux_binfmt. This is not a problem, since the set of registered binfmts on typical box is very small -- (ELF + something distro enabled for you). Test-booted, played with executable .txt files, modprobe/rmmod binfmt_misc. Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/kernel/irixelf.c | 7 ++++-- arch/sparc64/kernel/binfmt_aout32.c | 7 ++++-- fs/exec.c | 34 +++++------------------------ include/linux/binfmts.h | 2 +- 4 files changed, 17 insertions(+), 33 deletions(-) diff --git a/arch/mips/kernel/irixelf.c b/arch/mips/kernel/irixelf.c index 8ef5cf4cc423..5a3fe43e3019 100644 --- a/arch/mips/kernel/irixelf.c +++ b/arch/mips/kernel/irixelf.c @@ -47,8 +47,11 @@ static int irix_core_dump(long signr, struct pt_regs * regs, struct file *file); static struct linux_binfmt irix_format = { - NULL, THIS_MODULE, load_irix_binary, load_irix_library, - irix_core_dump, PAGE_SIZE + .module = THIS_MODULE, + .load_binary = load_irix_binary, + .load_shlib = load_irix_library, + .core_dump = irix_core_dump, + .min_coredump = PAGE_SIZE, }; /* Debugging routines. */ diff --git a/arch/sparc64/kernel/binfmt_aout32.c b/arch/sparc64/kernel/binfmt_aout32.c index d208cc7804f2..c8acbeab49b4 100644 --- a/arch/sparc64/kernel/binfmt_aout32.c +++ b/arch/sparc64/kernel/binfmt_aout32.c @@ -38,8 +38,11 @@ static int load_aout32_library(struct file*); static int aout32_core_dump(long signr, struct pt_regs * regs, struct file *file); static struct linux_binfmt aout32_format = { - NULL, THIS_MODULE, load_aout32_binary, load_aout32_library, aout32_core_dump, - PAGE_SIZE + .module = THIS_MODULE, + .load_binary = load_aout32_binary, + .load_shlib = load_aout32_library, + .core_dump = aout32_core_dump, + .min_coredump = PAGE_SIZE, }; static void set_brk(unsigned long start, unsigned long end) diff --git a/fs/exec.c b/fs/exec.c index 073b0b8c6d05..65825bdc4475 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -66,27 +66,15 @@ int suid_dumpable = 0; EXPORT_SYMBOL(suid_dumpable); /* The maximal length of core_pattern is also specified in sysctl.c */ -static struct linux_binfmt *formats; +static LIST_HEAD(formats); static DEFINE_RWLOCK(binfmt_lock); int register_binfmt(struct linux_binfmt * fmt) { - struct linux_binfmt ** tmp = &formats; - if (!fmt) return -EINVAL; - if (fmt->next) - return -EBUSY; write_lock(&binfmt_lock); - while (*tmp) { - if (fmt == *tmp) { - write_unlock(&binfmt_lock); - return -EBUSY; - } - tmp = &(*tmp)->next; - } - fmt->next = formats; - formats = fmt; + list_add(&fmt->lh, &formats); write_unlock(&binfmt_lock); return 0; } @@ -95,20 +83,10 @@ EXPORT_SYMBOL(register_binfmt); int unregister_binfmt(struct linux_binfmt * fmt) { - struct linux_binfmt ** tmp = &formats; - write_lock(&binfmt_lock); - while (*tmp) { - if (fmt == *tmp) { - *tmp = fmt->next; - fmt->next = NULL; - write_unlock(&binfmt_lock); - return 0; - } - tmp = &(*tmp)->next; - } + list_del(&fmt->lh); write_unlock(&binfmt_lock); - return -EINVAL; + return 0; } EXPORT_SYMBOL(unregister_binfmt); @@ -155,7 +133,7 @@ asmlinkage long sys_uselib(const char __user * library) struct linux_binfmt * fmt; read_lock(&binfmt_lock); - for (fmt = formats ; fmt ; fmt = fmt->next) { + list_for_each_entry(fmt, &formats, lh) { if (!fmt->load_shlib) continue; if (!try_module_get(fmt->module)) @@ -1284,7 +1262,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) retval = -ENOENT; for (try=0; try<2; try++) { read_lock(&binfmt_lock); - for (fmt = formats ; fmt ; fmt = fmt->next) { + list_for_each_entry(fmt, &formats, lh) { int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; if (!fn) continue; diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index 91c8c07fe8b7..6b834dcd20b0 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -63,7 +63,7 @@ struct linux_binprm{ * linux accepts. */ struct linux_binfmt { - struct linux_binfmt * next; + struct list_head lh; struct module *module; int (*load_binary)(struct linux_binprm *, struct pt_regs * regs); int (*load_shlib)(struct file *); -- 2.20.1