Revert "tty: hvc: pass DMA capable memory to put_chars()"

This reverts commit 0986d7bc5598f5df30e3db777d00e73890c97627.

It still has some issues and needs to be dropped at this point in time.

Link: https://lore.kernel.org/r/208f7a41-a9fa-630c-cb44-c37c503f3a72@kernel.org
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Cc: Xianting Tian <xianting.tian@linux.alibaba.com>
Cc: Shile Zhang <shile.zhang@linux.alibaba.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index 5bdb3df..4802cfa 100644 (file)
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -41,6 +41,16 @@
  */
 #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
 
+/*
+ * These sizes are most efficient for vio, because they are the
+ * native transfer size. We could make them selectable in the
+ * future to better deal with backends that want other buffer sizes.
+ */
+#define N_OUTBUF       16
+#define N_INBUF                16
+
+#define __ALIGNED__ __attribute__((__aligned__(L1_CACHE_BYTES)))
+
 static struct tty_driver *hvc_driver;
 static struct task_struct *hvc_task;
 
@@ -132,7 +142,6 @@ static int hvc_flush(struct hvc_struct *hp)
 static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
        {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
-static struct hvc_struct *cons_hvcs[MAX_NR_HVC_CONSOLES];
 
 /*
  * Console APIs, NOT TTY.  These APIs are available immediately when
@@ -142,11 +151,9 @@ static struct hvc_struct *cons_hvcs[MAX_NR_HVC_CONSOLES];
 static void hvc_console_print(struct console *co, const char *b,
                              unsigned count)
 {
-       char *c;
+       char c[N_OUTBUF] __ALIGNED__;
        unsigned i = 0, n = 0;
        int r, donecr = 0, index = co->index;
-       unsigned long flags;
-       struct hvc_struct *hp;
 
        /* Console access attempt outside of acceptable console range. */
        if (index >= MAX_NR_HVC_CONSOLES)
@@ -156,13 +163,6 @@ static void hvc_console_print(struct console *co, const char *b,
        if (vtermnos[index] == -1)
                return;
 
-       hp = cons_hvcs[index];
-       if (!hp)
-               return;
-
-       c = hp->cons_outbuf;
-
-       spin_lock_irqsave(&hp->cons_outbuf_lock, flags);
        while (count > 0 || i > 0) {
                if (count > 0 && i < sizeof(c)) {
                        if (b[n] == '\n' && !donecr) {
@@ -191,7 +191,6 @@ static void hvc_console_print(struct console *co, const char *b,
                        }
                }
        }
-       spin_unlock_irqrestore(&hp->cons_outbuf_lock, flags);
        hvc_console_flush(cons_ops[index], vtermnos[index]);
 }
 
@@ -879,13 +878,9 @@ static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch)
        struct tty_struct *tty = driver->ttys[0];
        struct hvc_struct *hp = tty->driver_data;
        int n;
-       unsigned long flags;
 
        do {
-               spin_lock_irqsave(&hp->cons_outbuf_lock, flags);
-               hp->cons_outbuf[0] = ch;
-               n = hp->ops->put_chars(hp->vtermno, &hp->cons_outbuf[0], 1);
-               spin_unlock_irqrestore(&hp->cons_outbuf_lock, flags);
+               n = hp->ops->put_chars(hp->vtermno, &ch, 1);
        } while (n <= 0);
 }
 #endif
@@ -927,7 +922,8 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
                        return ERR_PTR(err);
        }
 
-       hp = kzalloc(struct_size(hp, outbuf, outbuf_size), GFP_KERNEL);
+       hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
+                       GFP_KERNEL);
        if (!hp)
                return ERR_PTR(-ENOMEM);
 
@@ -935,13 +931,13 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
        hp->data = data;
        hp->ops = ops;
        hp->outbuf_size = outbuf_size;
+       hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
 
        tty_port_init(&hp->port);
        hp->port.ops = &hvc_port_ops;
 
        INIT_WORK(&hp->tty_resize, hvc_set_winsz);
        spin_lock_init(&hp->lock);
-       spin_lock_init(&hp->cons_outbuf_lock);
        mutex_lock(&hvc_structs_mutex);
 
        /*
@@ -968,7 +964,6 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
        if (i < MAX_NR_HVC_CONSOLES) {
                cons_ops[i] = ops;
                vtermnos[i] = vtermno;
-               cons_hvcs[i] = hp;
        }
 
        list_add_tail(&(hp->next), &hvc_structs);
@@ -993,7 +988,6 @@ int hvc_remove(struct hvc_struct *hp)
        if (hp->index < MAX_NR_HVC_CONSOLES) {
                vtermnos[hp->index] = -1;
                cons_ops[hp->index] = NULL;
-               cons_hvcs[hp->index] = NULL;
        }
 
        /* Don't whack hp->irq because tty_hangup() will need to free the irq. */

diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h
index 2c32ab6..18d0058 100644 (file)
--- a/drivers/tty/hvc/hvc_console.h
+++ b/drivers/tty/hvc/hvc_console.h
@@ -32,21 +32,12 @@
  */
 #define HVC_ALLOC_TTY_ADAPTERS 8
 
-/*
- * These sizes are most efficient for vio, because they are the
- * native transfer size. We could make them selectable in the
- * future to better deal with backends that want other buffer sizes.
- */
-#define N_OUTBUF       16
-#define N_INBUF                16
-
-#define __ALIGNED__ __attribute__((__aligned__(L1_CACHE_BYTES)))
-
 struct hvc_struct {
        struct tty_port port;
        spinlock_t lock;
        int index;
        int do_wakeup;
+       char *outbuf;
        int outbuf_size;
        int n_outbuf;
        uint32_t vtermno;
@@ -57,16 +48,6 @@ struct hvc_struct {
        struct work_struct tty_resize;
        struct list_head next;
        unsigned long flags;
-
-       /*
-        * the buf and its lock are used in hvc console api for putting chars,
-        * and also used in hvc_poll_put_char() for putting single char.
-        */
-       spinlock_t cons_outbuf_lock;
-       char cons_outbuf[N_OUTBUF] __ALIGNED__;
-
-       /* the buf is used for putting chars to tty */
-       char outbuf[] __ALIGNED__;
 };
 
 /* implemented by a low level driver */