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tty: Compute flip buffer ptrs

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The char_buf_ptr and flag_buf_ptr values are trivially derived from
the .data field offset; compute values as needed.

Fixes a long-standing type-mismatch with the char and flag ptrs.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-06-15 09:36:01 -04:00 committed by Greg Kroah-Hartman
parent f0f947c124
commit 1fc359fc3e
3 changed files with 22 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/tty/tty_buffer.c
View File

@ -71,8 +71,6 @@ static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size)
p->next = NULL;
p->commit = 0;
p->read = 0;
p->char_buf_ptr = (char *)(p->data);
p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
port->buf.memory_used += size;
return p;
}
@ -265,8 +263,8 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port,
if (unlikely(space == 0)) {
break;
}
memcpy(tb->char_buf_ptr + tb->used, chars, space);
memset(tb->flag_buf_ptr + tb->used, flag, space);
memcpy(char_buf_ptr(tb, tb->used), chars, space);
memset(flag_buf_ptr(tb, tb->used), flag, space);
tb->used += space;
copied += space;
chars += space;
@ -303,8 +301,8 @@ int tty_insert_flip_string_flags(struct tty_port *port,
if (unlikely(space == 0)) {
break;
}
memcpy(tb->char_buf_ptr + tb->used, chars, space);
memcpy(tb->flag_buf_ptr + tb->used, flags, space);
memcpy(char_buf_ptr(tb, tb->used), chars, space);
memcpy(flag_buf_ptr(tb, tb->used), flags, space);
tb->used += space;
copied += space;
chars += space;
@ -364,8 +362,8 @@ int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars,
int space = tty_buffer_request_room(port, size);
if (likely(space)) {
struct tty_buffer *tb = port->buf.tail;
*chars = tb->char_buf_ptr + tb->used;
memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
*chars = char_buf_ptr(tb, tb->used);
memset(flag_buf_ptr(tb, tb->used), TTY_NORMAL, space);
tb->used += space;
}
return space;
@ -394,8 +392,8 @@ int tty_prepare_flip_string_flags(struct tty_port *port,
int space = tty_buffer_request_room(port, size);
if (likely(space)) {
struct tty_buffer *tb = port->buf.tail;
*chars = tb->char_buf_ptr + tb->used;
*flags = tb->flag_buf_ptr + tb->used;
*chars = char_buf_ptr(tb, tb->used);
*flags = flag_buf_ptr(tb, tb->used);
tb->used += space;
}
return space;
@ -407,8 +405,8 @@ static int
receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
{
struct tty_ldisc *disc = tty->ldisc;
char *p = head->char_buf_ptr + head->read;
unsigned char *f = head->flag_buf_ptr + head->read;
unsigned char *p = char_buf_ptr(head, head->read);
char *f = flag_buf_ptr(head, head->read);
if (disc->ops->receive_buf2)
count = disc->ops->receive_buf2(tty, p, f, count);

12
include/linux/tty.h
View File

@ -31,8 +31,6 @@
struct tty_buffer {
struct tty_buffer *next;
char *char_buf_ptr;
unsigned char *flag_buf_ptr;
int used;
int size;
int commit;
@ -41,6 +39,16 @@ struct tty_buffer {
unsigned long data[0];
};
static inline unsigned char *char_buf_ptr(struct tty_buffer *b, int ofs)
{
return ((unsigned char *)b->data) + ofs;
}
static inline char *flag_buf_ptr(struct tty_buffer *b, int ofs)
{
return (char *)char_buf_ptr(b, ofs) + b->size;
}
/*
* We default to dicing tty buffer allocations to this many characters
* in order to avoid multiple page allocations. We know the size of

4
include/linux/tty_flip.h
View File

@ -18,8 +18,8 @@ static inline int tty_insert_flip_char(struct tty_port *port,
{
struct tty_buffer *tb = port->buf.tail;
if (tb && tb->used < tb->size) {
tb->flag_buf_ptr[tb->used] = flag;
tb->char_buf_ptr[tb->used++] = ch;
*flag_buf_ptr(tb, tb->used) = flag;
*char_buf_ptr(tb, tb->used++) = ch;
return 1;
}
return tty_insert_flip_string_flags(port, &ch, &flag, 1);