1 files changed, 76 insertions, 56 deletions

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 6f366f257fba..ddd74d41cbb2 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -29,17 +29,19 @@
 
 void tty_buffer_free_all(struct tty_struct *tty)
 {
+        struct tty_bufhead *buf = &tty->buf;
         struct tty_buffer *thead;
-        while ((thead = tty->buf.head) != NULL) {
-                tty->buf.head = thead->next;
+
+        while ((thead = buf->head) != NULL) {
+                buf->head = thead->next;
                 kfree(thead);
         }
-        while ((thead = tty->buf.free) != NULL) {
-                tty->buf.free = thead->next;
+        while ((thead = buf->free) != NULL) {
+                buf->free = thead->next;
                 kfree(thead);
         }
-        tty->buf.tail = NULL;
-        tty->buf.memory_used = 0;
+        buf->tail = NULL;
+        buf->memory_used = 0;
 }
 
 /**
@@ -87,15 +89,17 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
 
 static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
 {
+        struct tty_bufhead *buf = &tty->buf;
+
         /* Dumb strategy for now - should keep some stats */
-        tty->buf.memory_used -= b->size;
-        WARN_ON(tty->buf.memory_used < 0);
+        buf->memory_used -= b->size;
+        WARN_ON(buf->memory_used < 0);
 
         if (b->size >= 512)
                 kfree(b);
         else {
-                b->next = tty->buf.free;
-                tty->buf.free = b;
+                b->next = buf->free;
+                buf->free = b;
         }
 }
 
@@ -112,13 +116,14 @@ static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
 
 static void __tty_buffer_flush(struct tty_struct *tty)
 {
+        struct tty_bufhead *buf = &tty->buf;
         struct tty_buffer *thead;
 
-        while ((thead = tty->buf.head) != NULL) {
-                tty->buf.head = thead->next;
+        while ((thead = buf->head) != NULL) {
+                buf->head = thead->next;
                 tty_buffer_free(tty, thead);
         }
-        tty->buf.tail = NULL;
+        buf->tail = NULL;
 }
 
 /**
@@ -135,21 +140,23 @@ static void __tty_buffer_flush(struct tty_struct *tty)
 void tty_buffer_flush(struct tty_struct *tty)
 {
         struct tty_port *port = tty->port;
+        struct tty_bufhead *buf = &tty->buf;
         unsigned long flags;
-        spin_lock_irqsave(&tty->buf.lock, flags);
+
+        spin_lock_irqsave(&buf->lock, flags);
 
         /* If the data is being pushed to the tty layer then we can't
            process it here. Instead set a flag and the flush_to_ldisc
            path will process the flush request before it exits */
         if (test_bit(TTYP_FLUSHING, &port->iflags)) {
                 set_bit(TTYP_FLUSHPENDING, &port->iflags);
-                spin_unlock_irqrestore(&tty->buf.lock, flags);
+                spin_unlock_irqrestore(&buf->lock, flags);
                 wait_event(tty->read_wait,
                                 test_bit(TTYP_FLUSHPENDING, &port->iflags) == 0);
                 return;
         } else
                 __tty_buffer_flush(tty);
-        spin_unlock_irqrestore(&tty->buf.lock, flags);
+        spin_unlock_irqrestore(&buf->lock, flags);
 }
 
 /**
@@ -197,12 +204,14 @@ static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
  */
 static int __tty_buffer_request_room(struct tty_struct *tty, size_t size)
 {
+        struct tty_bufhead *buf = &tty->buf;
         struct tty_buffer *b, *n;
         int left;
         /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
            remove this conditional if its worth it. This would be invisible
            to the callers */
-        if ((b = tty->buf.tail) != NULL)
+        b = buf->tail;
+        if (b != NULL)
                 left = b->size - b->used;
         else
                 left = 0;
@@ -214,8 +223,8 @@ static int __tty_buffer_request_room(struct tty_struct *tty, size_t size)
                                 b->next = n;
                                 b->commit = b->used;
                         } else
-                                tty->buf.head = n;
-                        tty->buf.tail = n;
+                                buf->head = n;
+                        buf->tail = n;
                 } else
                         size = left;
         }
@@ -262,6 +271,7 @@ EXPORT_SYMBOL_GPL(tty_buffer_request_room);
 int tty_insert_flip_string_fixed_flag(struct tty_struct *tty,
                 const unsigned char *chars, char flag, size_t size)
 {
+        struct tty_bufhead *buf = &tty->buf;
         int copied = 0;
         do {
                 int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
@@ -269,18 +279,18 @@ int tty_insert_flip_string_fixed_flag(struct tty_struct *tty,
                 unsigned long flags;
                 struct tty_buffer *tb;
 
-                spin_lock_irqsave(&tty->buf.lock, flags);
+                spin_lock_irqsave(&buf->lock, flags);
                 space = __tty_buffer_request_room(tty, goal);
-                tb = tty->buf.tail;
+                tb = buf->tail;
                 /* If there is no space then tb may be NULL */
                 if (unlikely(space == 0)) {
-                        spin_unlock_irqrestore(&tty->buf.lock, flags);
+                        spin_unlock_irqrestore(&buf->lock, flags);
                         break;
                 }
                 memcpy(tb->char_buf_ptr + tb->used, chars, space);
                 memset(tb->flag_buf_ptr + tb->used, flag, space);
                 tb->used += space;
-                spin_unlock_irqrestore(&tty->buf.lock, flags);
+                spin_unlock_irqrestore(&buf->lock, flags);
                 copied += space;
                 chars += space;
                 /* There is a small chance that we need to split the data over
@@ -307,6 +317,7 @@ EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag);
 int tty_insert_flip_string_flags(struct tty_struct *tty,
                 const unsigned char *chars, const char *flags, size_t size)
 {
+        struct tty_bufhead *buf = &tty->buf;
         int copied = 0;
         do {
                 int goal = min_t(size_t, size - copied, TTY_BUFFER_PAGE);
@@ -314,18 +325,18 @@ int tty_insert_flip_string_flags(struct tty_struct *tty,
                 unsigned long __flags;
                 struct tty_buffer *tb;
 
-                spin_lock_irqsave(&tty->buf.lock, __flags);
+                spin_lock_irqsave(&buf->lock, __flags);
                 space = __tty_buffer_request_room(tty, goal);
-                tb = tty->buf.tail;
+                tb = buf->tail;
                 /* If there is no space then tb may be NULL */
                 if (unlikely(space == 0)) {
-                        spin_unlock_irqrestore(&tty->buf.lock, __flags);
+                        spin_unlock_irqrestore(&buf->lock, __flags);
                         break;
                 }
                 memcpy(tb->char_buf_ptr + tb->used, chars, space);
                 memcpy(tb->flag_buf_ptr + tb->used, flags, space);
                 tb->used += space;
-                spin_unlock_irqrestore(&tty->buf.lock, __flags);
+                spin_unlock_irqrestore(&buf->lock, __flags);
                 copied += space;
                 chars += space;
                 flags += space;
@@ -351,12 +362,14 @@ EXPORT_SYMBOL(tty_insert_flip_string_flags);
 
 void tty_schedule_flip(struct tty_struct *tty)
 {
+        struct tty_bufhead *buf = &tty->buf;
         unsigned long flags;
-        spin_lock_irqsave(&tty->buf.lock, flags);
-        if (tty->buf.tail != NULL)
-                tty->buf.tail->commit = tty->buf.tail->used;
-        spin_unlock_irqrestore(&tty->buf.lock, flags);
-        schedule_work(&tty->buf.work);
+
+        spin_lock_irqsave(&buf->lock, flags);
+        if (buf->tail != NULL)
+                buf->tail->commit = buf->tail->used;
+        spin_unlock_irqrestore(&buf->lock, flags);
+        schedule_work(&buf->work);
 }
 EXPORT_SYMBOL(tty_schedule_flip);
 
@@ -378,20 +391,21 @@ EXPORT_SYMBOL(tty_schedule_flip);
 int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars,
                                                                 size_t size)
 {
+        struct tty_bufhead *buf = &tty->buf;
         int space;
         unsigned long flags;
         struct tty_buffer *tb;
 
-        spin_lock_irqsave(&tty->buf.lock, flags);
+        spin_lock_irqsave(&buf->lock, flags);
         space = __tty_buffer_request_room(tty, size);
 
-        tb = tty->buf.tail;
+        tb = buf->tail;
         if (likely(space)) {
                 *chars = tb->char_buf_ptr + tb->used;
                 memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
                 tb->used += space;
         }
-        spin_unlock_irqrestore(&tty->buf.lock, flags);
+        spin_unlock_irqrestore(&buf->lock, flags);
         return space;
 }
 EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
@@ -415,20 +429,21 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
 int tty_prepare_flip_string_flags(struct tty_struct *tty,
                         unsigned char **chars, char **flags, size_t size)
 {
+        struct tty_bufhead *buf = &tty->buf;
         int space;
         unsigned long __flags;
         struct tty_buffer *tb;
 
-        spin_lock_irqsave(&tty->buf.lock, __flags);
+        spin_lock_irqsave(&buf->lock, __flags);
         space = __tty_buffer_request_room(tty, size);
 
-        tb = tty->buf.tail;
+        tb = buf->tail;
         if (likely(space)) {
                 *chars = tb->char_buf_ptr + tb->used;
                 *flags = tb->flag_buf_ptr + tb->used;
                 tb->used += space;
         }
-        spin_unlock_irqrestore(&tty->buf.lock, __flags);
+        spin_unlock_irqrestore(&buf->lock, __flags);
         return space;
 }
 EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
@@ -452,6 +467,7 @@ static void flush_to_ldisc(struct work_struct *work)
         struct tty_struct *tty =
                 container_of(work, struct tty_struct, buf.work);
         struct tty_port *port = tty->port;
+        struct tty_bufhead *buf = &tty->buf;
         unsigned long   flags;
         struct tty_ldisc *disc;
 
@@ -459,11 +475,11 @@ static void flush_to_ldisc(struct work_struct *work)
         if (disc == NULL)       /*  !TTY_LDISC */
                 return;
 
-        spin_lock_irqsave(&tty->buf.lock, flags);
+        spin_lock_irqsave(&buf->lock, flags);
 
         if (!test_and_set_bit(TTYP_FLUSHING, &port->iflags)) {
                 struct tty_buffer *head;
-                while ((head = tty->buf.head) != NULL) {
+                while ((head = buf->head) != NULL) {
                         int count;
                         char *char_buf;
                         unsigned char *flag_buf;
@@ -472,7 +488,7 @@ static void flush_to_ldisc(struct work_struct *work)
                         if (!count) {
                                 if (head->next == NULL)
                                         break;
-                                tty->buf.head = head->next;
+                                buf->head = head->next;
                                 tty_buffer_free(tty, head);
                                 continue;
                         }
@@ -488,10 +504,10 @@ static void flush_to_ldisc(struct work_struct *work)
                         char_buf = head->char_buf_ptr + head->read;
                         flag_buf = head->flag_buf_ptr + head->read;
                         head->read += count;
-                        spin_unlock_irqrestore(&tty->buf.lock, flags);
+                        spin_unlock_irqrestore(&buf->lock, flags);
                         disc->ops->receive_buf(tty, char_buf,
                                                         flag_buf, count);
-                        spin_lock_irqsave(&tty->buf.lock, flags);
+                        spin_lock_irqsave(&buf->lock, flags);
                 }
                 clear_bit(TTYP_FLUSHING, &port->iflags);
         }
@@ -503,7 +519,7 @@ static void flush_to_ldisc(struct work_struct *work)
                 clear_bit(TTYP_FLUSHPENDING, &port->iflags);
                 wake_up(&tty->read_wait);
         }
-        spin_unlock_irqrestore(&tty->buf.lock, flags);
+        spin_unlock_irqrestore(&buf->lock, flags);
 
         tty_ldisc_deref(disc);
 }
@@ -537,16 +553,18 @@ void tty_flush_to_ldisc(struct tty_struct *tty)
 
 void tty_flip_buffer_push(struct tty_struct *tty)
 {
+        struct tty_bufhead *buf = &tty->buf;
         unsigned long flags;
-        spin_lock_irqsave(&tty->buf.lock, flags);
-        if (tty->buf.tail != NULL)
-                tty->buf.tail->commit = tty->buf.tail->used;
-        spin_unlock_irqrestore(&tty->buf.lock, flags);
+
+        spin_lock_irqsave(&buf->lock, flags);
+        if (buf->tail != NULL)
+                buf->tail->commit = buf->tail->used;
+        spin_unlock_irqrestore(&buf->lock, flags);
 
         if (tty->low_latency)
-                flush_to_ldisc(&tty->buf.work);
+                flush_to_ldisc(&buf->work);
         else
-                schedule_work(&tty->buf.work);
+                schedule_work(&buf->work);
 }
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
@@ -562,11 +580,13 @@ EXPORT_SYMBOL(tty_flip_buffer_push);
 
 void tty_buffer_init(struct tty_struct *tty)
 {
-        spin_lock_init(&tty->buf.lock);
-        tty->buf.head = NULL;
-        tty->buf.tail = NULL;
-        tty->buf.free = NULL;
-        tty->buf.memory_used = 0;
-        INIT_WORK(&tty->buf.work, flush_to_ldisc);
+        struct tty_bufhead *buf = &tty->buf;
+
+        spin_lock_init(&buf->lock);
+        buf->head = NULL;
+        buf->tail = NULL;
+        buf->free = NULL;
+        buf->memory_used = 0;
+        INIT_WORK(&buf->work, flush_to_ldisc);
 }