tty: n_tty: use MASK() for masking out size bits

In n_tty, there is already a macro to mask out top bits from ring buffer
counters. It is MASK() added some time ago. So use it more in the code
to make it more readable.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230827074147.2287-7-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 7f8f6cfa884385a3858ab5a090332e21dafe0834..07b6a013b5ab0b1f6b930e7d618ca5e2063cd74a 100644 (file)
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -138,23 +138,23 @@ static inline size_t read_cnt(struct n_tty_data *ldata)
 
 static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i)
 {
-       return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
+       return ldata->read_buf[MASK(i)];
 }
 
 static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i)
 {
-       return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
+       return &ldata->read_buf[MASK(i)];
 }
 
 static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i)
 {
        smp_rmb(); /* Matches smp_wmb() in add_echo_byte(). */
-       return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
+       return ldata->echo_buf[MASK(i)];
 }
 
 static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
 {
-       return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
+       return &ldata->echo_buf[MASK(i)];
 }
 
 /* If we are not echoing the data, perhaps this is a secret so erase it */
@@ -1359,7 +1359,7 @@ static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c,
                                put_tty_queue(c, ldata);
 
 handle_newline:
-                       set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
+                       set_bit(MASK(ldata->read_head), ldata->read_flags);
                        put_tty_queue(c, ldata);
                        smp_store_release(&ldata->canon_head, ldata->read_head);
                        kill_fasync(&tty->fasync, SIGIO, POLL_IN);
@@ -1505,14 +1505,14 @@ n_tty_receive_buf_real_raw(const struct tty_struct *tty, const u8 *cp,
        struct n_tty_data *ldata = tty->disc_data;
        size_t n, head;
 
-       head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
+       head = MASK(ldata->read_head);
        n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
        memcpy(read_buf_addr(ldata, head), cp, n);
        ldata->read_head += n;
        cp += n;
        count -= n;
 
-       head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
+       head = MASK(ldata->read_head);
        n = min_t(size_t, count, N_TTY_BUF_SIZE - head);
        memcpy(read_buf_addr(ldata, head), cp, n);
        ldata->read_head += n;
@@ -1779,8 +1779,7 @@ static void n_tty_set_termios(struct tty_struct *tty, const struct ktermios *old
                        ldata->canon_head = ldata->read_tail;
                        ldata->push = 0;
                } else {
-                       set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1),
-                               ldata->read_flags);
+                       set_bit(MASK(ldata->read_head - 1), ldata->read_flags);
                        ldata->canon_head = ldata->read_head;
                        ldata->push = 1;
                }
@@ -1941,7 +1940,7 @@ static bool copy_from_read_buf(const struct tty_struct *tty,
        size_t n;
        bool is_eof;
        size_t head = smp_load_acquire(&ldata->commit_head);
-       size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
+       size_t tail = MASK(ldata->read_tail);
 
        n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
        n = min(*nr, n);
@@ -2004,7 +2003,7 @@ static bool canon_copy_from_read_buf(const struct tty_struct *tty,
        canon_head = smp_load_acquire(&ldata->canon_head);
        n = min(*nr, canon_head - ldata->read_tail);
 
-       tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
+       tail = MASK(ldata->read_tail);
        size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
 
        n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
@@ -2466,7 +2465,7 @@ static unsigned long inq_canon(struct n_tty_data *ldata)
        nr = head - tail;
        /* Skip EOF-chars.. */
        while (MASK(head) != MASK(tail)) {
-               if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
+               if (test_bit(MASK(tail), ldata->read_flags) &&
                    read_buf(ldata, tail) == __DISABLED_CHAR)
                        nr--;
                tail++;