Andrew Morton wrote:
> What is that "for (try=0; try<2" loop actually there for? To retry
> after the request_module(), it appears. Which is pointless if
> !CONFIG_MODULES.
Indeed. This loop was introduced in Linux 1.3.57 (where CONFIG_KERNELD was
introduced). Comparing between 1.3.56 and 1.3.57, there is no reason to retry
if !CONFIG_KERNELD, for get_fs_type() in fs/super.c and dev_get() in
net/core/dev.c do not retry if !CONFIG_KERNELD.
struct file_system_type *get_fs_type(const char *name)
{
struct file_system_type * fs = file_systems;
if (!name)
return fs;
for (fs = file_systems; fs && strcmp(fs->name, name); fs = fs->next)
;
#ifdef CONFIG_KERNELD
if (!fs && (request_module(name) == 0)) {
for (fs = file_systems; fs && strcmp(fs->name, name); fs = fs->next)
;
}
#endif
return fs;
}
struct device *dev_get(const char *name)
{
struct device *dev;
for (dev = dev_base; dev != NULL; dev = dev->next)
{
if (strcmp(dev->name, name) == 0)
return(dev);
}
#ifdef CONFIG_KERNELD
if (request_module(name) == 0)
for (dev = dev_base; dev != NULL; dev = dev->next) {
if (strcmp(dev->name, name) == 0)
return(dev);
}
#endif
return(NULL);
}
It is likely that we have been doing needless retry if !CONFIG_MODULES.
----------------------------------------
[PATCH] exec: Do not retry load_binary method if CONFIG_MODULES=n.
If CONFIG_MODULES=n, it makes no sense to retry the list of binary formats
handler because the list will not be modified by request_module().
Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
diff --git a/fs/exec.c b/fs/exec.c
index 6075a1e..46c399f 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1401,9 +1401,9 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
}
}
read_unlock(&binfmt_lock);
+#ifdef CONFIG_MODULES
if (retval != -ENOEXEC || bprm->mm == NULL) {
break;
-#ifdef CONFIG_MODULES
} else {
#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
if (printable(bprm->buf[0]) &&
@@ -1412,8 +1412,10 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
printable(bprm->buf[3]))
break; /* -ENOEXEC */
request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
-#endif
}
+#else
+ break;
+#endif
}
return retval;
}
--
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