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Date: Wed, 26 Sep 2018 18:29:11 +0200
From: Julian Wiedmann <jwi@...ux.ibm.com>
To: David Miller <davem@...emloft.net>
Cc: <netdev@...r.kernel.org>, <linux-s390@...r.kernel.org>,
Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Stefan Raspl <raspl@...ux.ibm.com>,
Ursula Braun <ubraun@...ux.ibm.com>,
Julian Wiedmann <jwi@...ux.ibm.com>
Subject: [PATCH net-next 10/15] s390/qeth: remove CARD_FROM_CDEV helper
The cdev-to-card translation walks through two layers of drvdata,
with no locking or refcounting (where eg. the ccwgroup core only
accesses a cdev's drvdata while holding the ccwlock).
This might be safe for now, but any careless usage of the helper has the
potential for subtle races and use-after-free's. Luckily there's only
one occurrence where we _really_ need it (in qeth_irq()), for any other
user we can just pass through an appropriate card pointer.
Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
---
drivers/s390/net/qeth_core_main.c | 73 ++++++++++++++++-----------------------
1 file changed, 29 insertions(+), 44 deletions(-)
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 86b9cce1f483..caa5d109841c 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -746,18 +746,10 @@ static int qeth_check_idx_response(struct qeth_card *card,
return 0;
}
-static struct qeth_card *CARD_FROM_CDEV(struct ccw_device *cdev)
-{
- struct qeth_card *card = dev_get_drvdata(&((struct ccwgroup_device *)
- dev_get_drvdata(&cdev->dev))->dev);
- return card;
-}
-
static struct qeth_cmd_buffer *__qeth_get_buffer(struct qeth_channel *channel)
{
__u8 index;
- QETH_CARD_TEXT(CARD_FROM_CDEV(channel->ccwdev), 6, "getbuff");
index = channel->io_buf_no;
do {
if (channel->iob[index].state == BUF_STATE_FREE) {
@@ -778,7 +770,6 @@ void qeth_release_buffer(struct qeth_channel *channel,
{
unsigned long flags;
- QETH_CARD_TEXT(CARD_FROM_CDEV(channel->ccwdev), 6, "relbuff");
spin_lock_irqsave(&channel->iob_lock, flags);
iob->state = BUF_STATE_FREE;
iob->callback = qeth_send_control_data_cb;
@@ -980,16 +971,15 @@ void qeth_schedule_recovery(struct qeth_card *card)
}
EXPORT_SYMBOL_GPL(qeth_schedule_recovery);
-static int qeth_get_problem(struct ccw_device *cdev, struct irb *irb)
+static int qeth_get_problem(struct qeth_card *card, struct ccw_device *cdev,
+ struct irb *irb)
{
int dstat, cstat;
char *sense;
- struct qeth_card *card;
sense = (char *) irb->ecw;
cstat = irb->scsw.cmd.cstat;
dstat = irb->scsw.cmd.dstat;
- card = CARD_FROM_CDEV(cdev);
if (cstat & (SCHN_STAT_CHN_CTRL_CHK | SCHN_STAT_INTF_CTRL_CHK |
SCHN_STAT_CHN_DATA_CHK | SCHN_STAT_CHAIN_CHECK |
@@ -1029,14 +1019,11 @@ static int qeth_get_problem(struct ccw_device *cdev, struct irb *irb)
return 0;
}
-static long __qeth_check_irb_error(struct ccw_device *cdev,
- unsigned long intparm, struct irb *irb)
+static long qeth_check_irb_error(struct qeth_card *card,
+ struct ccw_device *cdev, unsigned long intparm,
+ struct irb *irb)
{
- struct qeth_card *card;
-
- card = CARD_FROM_CDEV(cdev);
-
- if (!card || !IS_ERR(irb))
+ if (!IS_ERR(irb))
return 0;
switch (PTR_ERR(irb)) {
@@ -1073,10 +1060,13 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
int rc;
int cstat, dstat;
struct qeth_cmd_buffer *iob = NULL;
+ struct ccwgroup_device *gdev;
struct qeth_channel *channel;
struct qeth_card *card;
- card = CARD_FROM_CDEV(cdev);
+ /* while we hold the ccwdev lock, this stays valid: */
+ gdev = dev_get_drvdata(&cdev->dev);
+ card = dev_get_drvdata(&gdev->dev);
if (!card)
return;
@@ -1096,7 +1086,7 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
if (qeth_intparm_is_iob(intparm))
iob = (struct qeth_cmd_buffer *) __va((addr_t)intparm);
- if (__qeth_check_irb_error(cdev, intparm, irb)) {
+ if (qeth_check_irb_error(card, cdev, intparm, irb)) {
/* IO was terminated, free its resources. */
if (iob)
qeth_release_buffer(iob->channel, iob);
@@ -1151,7 +1141,7 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
channel->state = CH_STATE_DOWN;
goto out;
}
- rc = qeth_get_problem(cdev, irb);
+ rc = qeth_get_problem(card, cdev, irb);
if (rc) {
card->read_or_write_problem = 1;
qeth_clear_ipacmd_list(card);
@@ -1514,12 +1504,11 @@ static struct qeth_card *qeth_alloc_card(struct ccwgroup_device *gdev)
return NULL;
}
-static int qeth_clear_channel(struct qeth_channel *channel)
+static int qeth_clear_channel(struct qeth_card *card,
+ struct qeth_channel *channel)
{
- struct qeth_card *card;
int rc;
- card = CARD_FROM_CDEV(channel->ccwdev);
QETH_CARD_TEXT(card, 3, "clearch");
spin_lock_irq(get_ccwdev_lock(channel->ccwdev));
rc = ccw_device_clear(channel->ccwdev, QETH_CLEAR_CHANNEL_PARM);
@@ -1537,12 +1526,11 @@ static int qeth_clear_channel(struct qeth_channel *channel)
return 0;
}
-static int qeth_halt_channel(struct qeth_channel *channel)
+static int qeth_halt_channel(struct qeth_card *card,
+ struct qeth_channel *channel)
{
- struct qeth_card *card;
int rc;
- card = CARD_FROM_CDEV(channel->ccwdev);
QETH_CARD_TEXT(card, 3, "haltch");
spin_lock_irq(get_ccwdev_lock(channel->ccwdev));
rc = ccw_device_halt(channel->ccwdev, QETH_HALT_CHANNEL_PARM);
@@ -1564,9 +1552,9 @@ static int qeth_halt_channels(struct qeth_card *card)
int rc1 = 0, rc2 = 0, rc3 = 0;
QETH_CARD_TEXT(card, 3, "haltchs");
- rc1 = qeth_halt_channel(&card->read);
- rc2 = qeth_halt_channel(&card->write);
- rc3 = qeth_halt_channel(&card->data);
+ rc1 = qeth_halt_channel(card, &card->read);
+ rc2 = qeth_halt_channel(card, &card->write);
+ rc3 = qeth_halt_channel(card, &card->data);
if (rc1)
return rc1;
if (rc2)
@@ -1579,9 +1567,9 @@ static int qeth_clear_channels(struct qeth_card *card)
int rc1 = 0, rc2 = 0, rc3 = 0;
QETH_CARD_TEXT(card, 3, "clearchs");
- rc1 = qeth_clear_channel(&card->read);
- rc2 = qeth_clear_channel(&card->write);
- rc3 = qeth_clear_channel(&card->data);
+ rc1 = qeth_clear_channel(card, &card->read);
+ rc2 = qeth_clear_channel(card, &card->write);
+ rc3 = qeth_clear_channel(card, &card->data);
if (rc1)
return rc1;
if (rc2)
@@ -1810,17 +1798,16 @@ static void qeth_init_func_level(struct qeth_card *card)
}
}
-static int qeth_idx_activate_get_answer(struct qeth_channel *channel,
+static int qeth_idx_activate_get_answer(struct qeth_card *card,
+ struct qeth_channel *channel,
void (*reply_cb)(struct qeth_card *,
struct qeth_channel *,
struct qeth_cmd_buffer *))
{
struct qeth_cmd_buffer *iob;
int rc;
- struct qeth_card *card;
QETH_DBF_TEXT(SETUP, 2, "idxanswr");
- card = CARD_FROM_CDEV(channel->ccwdev);
iob = qeth_get_buffer(channel);
if (!iob)
return -ENOMEM;
@@ -1854,20 +1841,18 @@ static int qeth_idx_activate_get_answer(struct qeth_channel *channel,
return rc;
}
-static int qeth_idx_activate_channel(struct qeth_channel *channel,
+static int qeth_idx_activate_channel(struct qeth_card *card,
+ struct qeth_channel *channel,
void (*reply_cb)(struct qeth_card *,
struct qeth_channel *,
struct qeth_cmd_buffer *))
{
- struct qeth_card *card;
struct qeth_cmd_buffer *iob;
__u16 temp;
__u8 tmp;
int rc;
struct ccw_dev_id temp_devid;
- card = CARD_FROM_CDEV(channel->ccwdev);
-
QETH_DBF_TEXT(SETUP, 2, "idxactch");
iob = qeth_get_buffer(channel);
@@ -1925,7 +1910,7 @@ static int qeth_idx_activate_channel(struct qeth_channel *channel,
QETH_DBF_TEXT_(SETUP, 2, "2err%d", -ETIME);
return -ETIME;
}
- return qeth_idx_activate_get_answer(channel, reply_cb);
+ return qeth_idx_activate_get_answer(card, channel, reply_cb);
}
static int qeth_peer_func_level(int level)
@@ -5131,7 +5116,7 @@ int qeth_core_hardsetup_card(struct qeth_card *card)
qeth_determine_capabilities(card);
qeth_init_tokens(card);
qeth_init_func_level(card);
- rc = qeth_idx_activate_channel(&card->read, qeth_idx_read_cb);
+ rc = qeth_idx_activate_channel(card, &card->read, qeth_idx_read_cb);
if (rc == -ERESTARTSYS) {
QETH_DBF_TEXT(SETUP, 2, "break2");
return rc;
@@ -5142,7 +5127,7 @@ int qeth_core_hardsetup_card(struct qeth_card *card)
else
goto retry;
}
- rc = qeth_idx_activate_channel(&card->write, qeth_idx_write_cb);
+ rc = qeth_idx_activate_channel(card, &card->write, qeth_idx_write_cb);
if (rc == -ERESTARTSYS) {
QETH_DBF_TEXT(SETUP, 2, "break3");
return rc;
--
2.16.4
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