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-rw-r--r--fs/proc/base.c33
1 files changed, 14 insertions, 19 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 4b27e26fc6de..3fcca77d45f1 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -215,8 +215,9 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
unsigned long arg_start, arg_end, env_start, env_end;
unsigned long len1, len2, len;
unsigned long p;
+ char __user *buf0 = buf;
char c;
- ssize_t rv;
+ int rv;
BUG_ON(*pos < 0);
@@ -253,25 +254,20 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
len2 = env_end - env_start;
/* Empty ARGV. */
- if (len1 == 0) {
- rv = 0;
- goto out_free_page;
- }
+ if (len1 == 0)
+ goto end;
+
/*
* Inherently racy -- command line shares address space
* with code and data.
*/
- if (access_remote_vm(mm, arg_end - 1, &c, 1, FOLL_ANON) != 1) {
- rv = 0;
- goto out_free_page;
- }
-
- rv = 0;
+ if (access_remote_vm(mm, arg_end - 1, &c, 1, FOLL_ANON) != 1)
+ goto end;
if (c == '\0') {
/* Command line (set of strings) occupies whole ARGV. */
if (len1 <= *pos)
- goto out_free_page;
+ goto end;
p = arg_start + *pos;
len = len1 - *pos;
@@ -281,7 +277,7 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
nr_read = min3(count, len, PAGE_SIZE);
nr_read = access_remote_vm(mm, p, page, nr_read, FOLL_ANON);
if (nr_read == 0)
- goto out_free_page;
+ goto end;
if (copy_to_user(buf, page, nr_read)) {
rv = -EFAULT;
@@ -292,7 +288,6 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
len -= nr_read;
buf += nr_read;
count -= nr_read;
- rv += nr_read;
}
} else {
/*
@@ -323,7 +318,7 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
nr_read = min3(count, len, PAGE_SIZE);
nr_read = access_remote_vm(mm, p, page, nr_read, FOLL_ANON);
if (nr_read == 0)
- goto out_free_page;
+ goto end;
/*
* Command line can be shorter than whole ARGV
@@ -340,10 +335,9 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
len -= nr_write;
buf += nr_write;
count -= nr_write;
- rv += nr_write;
if (nr_write < nr_read)
- goto out_free_page;
+ goto end;
}
/* Only first chunk can be read partially. */
@@ -352,12 +346,13 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
}
}
+end:
+ *pos += buf - buf0;
+ rv = buf - buf0;
out_free_page:
free_page((unsigned long)page);
out_mmput:
mmput(mm);
- if (rv > 0)
- *pos += rv;
return rv;
}