Add a temporary for the computed source address and substitute
where appropriate. No functional change.
Signed-off-by: Peter Hurley <[email protected]>
---
drivers/tty/n_tty.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index b2b01d5..bc613b8 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2014,11 +2014,11 @@ static int copy_from_read_buf(struct tty_struct *tty,
n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
n = min(*nr, n);
if (n) {
- retval = copy_to_user(*b, read_buf_addr(ldata, tail), n);
+ const unsigned char *from = read_buf_addr(ldata, tail);
+ retval = copy_to_user(*b, from, n);
n -= retval;
- is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty);
- tty_audit_add_data(tty, read_buf_addr(ldata, tail), n,
- ldata->icanon);
+ is_eof = n == 1 && *from == EOF_CHAR(tty);
+ tty_audit_add_data(tty, from, n, ldata->icanon);
smp_store_release(&ldata->read_tail, ldata->read_tail + n);
/* Turn single EOF into zero-length read */
if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
--
2.6.3
Merge the multiple tty_copy_to_user() calls into a single copy
sequence within tty_copy_to_user().
Signed-off-by: Peter Hurley <[email protected]>
---
Requires: "tty: audit: Fix audit source"
drivers/tty/n_tty.c | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index c37c15d..b2b01d5 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -162,12 +162,23 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
return put_user(x, ptr);
}
-static inline int tty_copy_to_user(struct tty_struct *tty,
- void __user *to,
- const void *from,
- unsigned long n)
+static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
+ size_t tail, size_t n)
{
struct n_tty_data *ldata = tty->disc_data;
+ size_t size = N_TTY_BUF_SIZE - tail;
+ const void *from = read_buf_addr(ldata, tail);
+ int uncopied;
+
+ if (n > size) {
+ tty_audit_add_data(tty, from, size, ldata->icanon);
+ uncopied = copy_to_user(to, from, size);
+ if (uncopied)
+ return uncopied;
+ to += size;
+ n -= size;
+ from = ldata->read_buf;
+ }
tty_audit_add_data(tty, from, n, ldata->icanon);
return copy_to_user(to, from, n);
@@ -2074,7 +2085,6 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
} else if (eol != size)
found = 1;
- size = N_TTY_BUF_SIZE - tail;
n = eol - tail;
if (n > N_TTY_BUF_SIZE)
n += N_TTY_BUF_SIZE;
@@ -2086,17 +2096,10 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
eof_push = !n && ldata->read_tail != ldata->line_start;
}
- n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
- __func__, eol, found, n, c, size, more);
-
- if (n > size) {
- ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size);
- if (ret)
- return -EFAULT;
- ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size);
- } else
- ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n);
+ n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n",
+ __func__, eol, found, n, c, tail, more);
+ ret = tty_copy_to_user(tty, *b, tail, n);
if (ret)
return -EFAULT;
*b += n;
--
2.6.3
Hi Greg,
This series rebases a couple of already-sent patches on top of the
EOF push bug fix, "n_tty: Fix poll() after buffer-limited eof push read",
and adds a third to reduce branching (which hopefully clarifies the
copy algorithm some).
I will also resend the "Rework tty audit" series, which requires this
series.
Regards,
Peter Hurley (3):
n_tty: Uninline tty_copy_to_user()
n_tty: Clarify copy_from_read_buf()
n_tty: Reduce branching in canon_copy_from_read_buf()
drivers/tty/n_tty.c | 48 +++++++++++++++++++++++++-----------------------
1 file changed, 25 insertions(+), 23 deletions(-)
--
2.6.3
Merge the multiple tty_copy_to_user() calls into a single copy
sequence within tty_copy_to_user().
Signed-off-by: Peter Hurley <[email protected]>
---
drivers/tty/n_tty.c | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index b4bc8ea..9a96f26 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -163,12 +163,23 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
return put_user(x, ptr);
}
-static inline int tty_copy_to_user(struct tty_struct *tty,
- void __user *to,
- const void *from,
- unsigned long n)
+static int tty_copy_to_user(struct tty_struct *tty, void __user *to,
+ size_t tail, size_t n)
{
struct n_tty_data *ldata = tty->disc_data;
+ size_t size = N_TTY_BUF_SIZE - tail;
+ const void *from = read_buf_addr(ldata, tail);
+ int uncopied;
+
+ if (n > size) {
+ tty_audit_add_data(tty, from, size, ldata->icanon);
+ uncopied = copy_to_user(to, from, size);
+ if (uncopied)
+ return uncopied;
+ to += size;
+ n -= size;
+ from = ldata->read_buf;
+ }
tty_audit_add_data(tty, from, n, ldata->icanon);
return copy_to_user(to, from, n);
@@ -2073,7 +2084,6 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
} else if (eol != size)
found = 1;
- size = N_TTY_BUF_SIZE - tail;
n = eol - tail;
if (n > N_TTY_BUF_SIZE)
n += N_TTY_BUF_SIZE;
@@ -2084,17 +2094,10 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
n = c;
}
- n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
- __func__, eol, found, n, c, size, more);
-
- if (n > size) {
- ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size);
- if (ret)
- return -EFAULT;
- ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size);
- } else
- ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n);
+ n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu tail:%zu more:%zu\n",
+ __func__, eol, found, n, c, tail, more);
+ ret = tty_copy_to_user(tty, *b, tail, n);
if (ret)
return -EFAULT;
*b += n;
--
2.6.3
Add a temporary for the computed source address and substitute
where appropriate. No functional change.
Signed-off-by: Peter Hurley <[email protected]>
---
drivers/tty/n_tty.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 9a96f26..eab606a 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2013,11 +2013,11 @@ static int copy_from_read_buf(struct tty_struct *tty,
n = min(head - ldata->read_tail, N_TTY_BUF_SIZE - tail);
n = min(*nr, n);
if (n) {
- retval = copy_to_user(*b, read_buf_addr(ldata, tail), n);
+ const unsigned char *from = read_buf_addr(ldata, tail);
+ retval = copy_to_user(*b, from, n);
n -= retval;
- is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty);
- tty_audit_add_data(tty, read_buf_addr(ldata, tail), n,
- ldata->icanon);
+ is_eof = n == 1 && *from == EOF_CHAR(tty);
+ tty_audit_add_data(tty, from, n, ldata->icanon);
smp_store_release(&ldata->read_tail, ldata->read_tail + n);
/* Turn single EOF into zero-length read */
if (L_EXTPROC(tty) && ldata->icanon && is_eof &&
--
2.6.3
Instead of compare-and-set, just compute 'found'.
Signed-off-by: Peter Hurley <[email protected]>
---
drivers/tty/n_tty.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index eab606a..9b0b610 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2079,10 +2079,9 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
if (eol == N_TTY_BUF_SIZE && more) {
/* scan wrapped without finding set bit */
eol = find_next_bit(ldata->read_flags, more, 0);
- if (eol != more)
- found = 1;
- } else if (eol != size)
- found = 1;
+ found = eol != more;
+ } else
+ found = eol != size;
n = eol - tail;
if (n > N_TTY_BUF_SIZE)
--
2.6.3