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 <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/mips/kernel/irixelf.c b/arch/mips/kernel/irixelf.c
index 8ef5cf4cc42355e846eddfd65382e3e83c820137..5a3fe43e3019cb56c3e722af0ce3622d1cb90150 100644 (file)
--- 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 d208cc7804f234583fc8e457f871a96610dfede6..c8acbeab49b482c0bd96d554edd12aad769214d6 100644 (file)
--- 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 073b0b8c6d055a3fd947f16fbdbe5552a6bc34c8..65825bdc4475f1706d45d46836a0f537e0b7aa71 100644 (file)
--- 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 91c8c07fe8b73fbf365cd7e4c67dd33a8e349a54..6b834dcd20b069c52aa97225a3d631d61dfdcbc7 100644 (file)
--- 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 *);