1 files changed, 9 insertions, 13 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index ed776149261e..e49c2bce551d 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2054,13 +2054,13 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
         size_t eol;
         size_t tail;
         int ret, found = 0;
-        bool eof_push = 0;
 
         /* N.B. avoid overrun if nr == 0 */
-        n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail);
-        if (!n)
+        if (!*nr)
                 return 0;
 
+        n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail);
+
         tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
         size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
 
@@ -2081,12 +2081,11 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
         n = eol - tail;
         if (n > N_TTY_BUF_SIZE)
                 n += N_TTY_BUF_SIZE;
-        n += found;
-        c = n;
+        c = n + found;
 
-        if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) {
-                n--;
-                eof_push = !n && ldata->read_tail != ldata->line_start;
+        if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) {
+                c = min(*nr, c);
+                n = c;
         }
 
         n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
@@ -2116,7 +2115,7 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
                         ldata->push = 0;
                 tty_audit_push(tty);
         }
-        return eof_push ? -EAGAIN : 0;
+        return 0;
 }
 
 extern ssize_t redirected_tty_write(struct file *, const char __user *,
@@ -2273,10 +2272,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
                 if (ldata->icanon && !L_EXTPROC(tty)) {
                         retval = canon_copy_from_read_buf(tty, &b, &nr);
-                        if (retval == -EAGAIN) {
-                                retval = 0;
-                                continue;
-                        } else if (retval)
+                        if (retval)
                                 break;
                 } else {
                         int uncopied;