From: Brian Norris <briannorris@chromium.org>
To: Ganapathi Bhat <gbhat@marvell.com>,
Nishant Sarmukadam <nishants@marvell.com>
Cc: <linux-kernel@vger.kernel.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Amitkumar Karwar <amitkarwar@gmail.com>,
Kalle Valo <kvalo@codeaurora.org>,
linux-wireless@vger.kernel.org,
Brian Norris <briannorris@chromium.org>
Subject: [PATCH 01/14] mwifiex: pcie: properly synchronize, disable interrupts in driver callbacks
Date: Wed, 24 May 2017 17:11:06 -0700 [thread overview]
Message-ID: <20170525001119.64791-1-briannorris@chromium.org> (raw)
It seems that the implicit assumption of the mwifiex
{enable,disable}_int() callbacks is that after ->disable_int(), all
interrupt handling should be complete (synchronized) and not fire again
until after ->enable_int(). Also, interrupts should not be serviced
until after the first ->enable_int().
However, the PCIe driver does none of this. First, the existing
interrupt mask programming appears to only have an effect for legacy
interrupts. It doesn't actually prevent MSI/MSI-X interrupts. Second,
even when it might mask interrupts, we're doing nothing to ensure that
pending IRQs have finished processing; they could be already in-flight
when a CPU masks them.
Another quirk of this driver's design is the use of a racy
"surprise_removed" check in mwifiex_pcie_interrupt(). This appears to
act like a racy poor-man's version of masking our interrupts -- it
allows us to short-circuit the ISR if it fires when we're not prepared
to handle more work.
We can resolve this all by:
(a) disabling our IRQs after requesting them
(b) call {enable,disable}_irq() in the {enable,disable}_int() callbacks
(c) remove the racy '->surprise_removed' hack from
mwifiex_pcie_interrupt()
(d) document the effect (or lack thereof) of PCIE_HOST_INT_MASK, to
clarify and possibly prevent future misuse
Along the way, I decided to use underscores to prefix the driver-private
forms of "disabling interrupts" (instead of the awkward "_noerr" suffix
used already), partly to discourage their use.
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
drivers/net/wireless/marvell/mwifiex/pcie.c | 70 ++++++++++++++++++++---------
1 file changed, 49 insertions(+), 21 deletions(-)
diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index 394224d6c219..ea75315bf19d 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -505,12 +505,10 @@ static int mwifiex_pm_wakeup_card_complete(struct mwifiex_adapter *adapter)
}
/*
- * This function disables the host interrupt.
- *
- * The host interrupt mask is read, the disable bit is reset and
- * written back to the card host interrupt mask register.
+ * This function masks the host interrupt. Effective only for legacy PCI
+ * interrupts.
*/
-static int mwifiex_pcie_disable_host_int(struct mwifiex_adapter *adapter)
+static int __mwifiex_pcie_disable_host_int(struct mwifiex_adapter *adapter)
{
if (mwifiex_pcie_ok_to_access_hw(adapter)) {
if (mwifiex_write_reg(adapter, PCIE_HOST_INT_MASK,
@@ -525,18 +523,30 @@ static int mwifiex_pcie_disable_host_int(struct mwifiex_adapter *adapter)
return 0;
}
-static void mwifiex_pcie_disable_host_int_noerr(struct mwifiex_adapter *adapter)
+/*
+ * Disable interrupts, synchronizing with any outstanding interrupts.
+ */
+static void mwifiex_pcie_disable_host_int(struct mwifiex_adapter *adapter)
{
- WARN_ON(mwifiex_pcie_disable_host_int(adapter));
+ struct pcie_service_card *card = adapter->card;
+ int i;
+
+ WARN_ON(__mwifiex_pcie_disable_host_int(adapter));
+
+ if (card->msix_enable) {
+ for (i = 0; i < MWIFIEX_NUM_MSIX_VECTORS; i++) {
+ disable_irq(card->msix_entries[i].vector);
+ }
+ } else {
+ disable_irq(card->dev->irq);
+ }
}
/*
- * This function enables the host interrupt.
- *
- * The host interrupt enable mask is written to the card
- * host interrupt mask register.
+ * This function unmasks the host interrupt. Effective only for legacy PCI
+ * interrupts.
*/
-static int mwifiex_pcie_enable_host_int(struct mwifiex_adapter *adapter)
+static int __mwifiex_pcie_enable_host_int(struct mwifiex_adapter *adapter)
{
if (mwifiex_pcie_ok_to_access_hw(adapter)) {
/* Simply write the mask to the register */
@@ -551,6 +561,26 @@ static int mwifiex_pcie_enable_host_int(struct mwifiex_adapter *adapter)
return 0;
}
+static int mwifiex_pcie_enable_host_int(struct mwifiex_adapter *adapter)
+{
+ struct pcie_service_card *card = adapter->card;
+ int i, ret;
+
+ ret = __mwifiex_pcie_enable_host_int(adapter);
+ if (ret)
+ return ret;
+
+ if (card->msix_enable) {
+ for (i = 0; i < MWIFIEX_NUM_MSIX_VECTORS; i++) {
+ enable_irq(card->msix_entries[i].vector);
+ }
+ } else {
+ enable_irq(card->dev->irq);
+ }
+
+ return 0;
+}
+
/*
* This function initializes TX buffer ring descriptors
*/
@@ -1738,7 +1768,7 @@ static int mwifiex_pcie_process_cmd_complete(struct mwifiex_adapter *adapter)
while (reg->sleep_cookie && (count++ < 10) &&
mwifiex_pcie_ok_to_access_hw(adapter))
usleep_range(50, 60);
- mwifiex_pcie_enable_host_int(adapter);
+ __mwifiex_pcie_enable_host_int(adapter);
mwifiex_process_sleep_confirm_resp(adapter, skb->data,
skb->len);
} else {
@@ -2081,7 +2111,7 @@ static int mwifiex_prog_fw_w_helper(struct mwifiex_adapter *adapter,
"info: Downloading FW image (%d bytes)\n",
firmware_len);
- if (mwifiex_pcie_disable_host_int(adapter)) {
+ if (__mwifiex_pcie_disable_host_int(adapter)) {
mwifiex_dbg(adapter, ERROR,
"%s: Disabling interrupts failed.\n", __func__);
return -1;
@@ -2335,8 +2365,7 @@ static void mwifiex_interrupt_status(struct mwifiex_adapter *adapter,
if ((pcie_ireg == 0xFFFFFFFF) || !pcie_ireg)
return;
-
- mwifiex_pcie_disable_host_int(adapter);
+ __mwifiex_pcie_disable_host_int(adapter);
/* Clear the pending interrupts */
if (mwifiex_write_reg(adapter, PCIE_HOST_INT_STATUS,
@@ -2387,9 +2416,6 @@ static irqreturn_t mwifiex_pcie_interrupt(int irq, void *context)
}
adapter = card->adapter;
- if (adapter->surprise_removed)
- goto exit;
-
if (card->msix_enable)
mwifiex_interrupt_status(adapter, ctx->msg_id);
else
@@ -2494,7 +2520,7 @@ static int mwifiex_process_pcie_int(struct mwifiex_adapter *adapter)
"info: cmd_sent=%d data_sent=%d\n",
adapter->cmd_sent, adapter->data_sent);
if (!card->msi_enable && adapter->ps_state != PS_STATE_SLEEP)
- mwifiex_pcie_enable_host_int(adapter);
+ __mwifiex_pcie_enable_host_int(adapter);
return 0;
}
@@ -3055,6 +3081,7 @@ static int mwifiex_pcie_request_irq(struct mwifiex_adapter *adapter)
&card->msix_ctx[i]);
if (ret)
break;
+ disable_irq(card->msix_entries[i].vector);
}
if (ret) {
@@ -3087,6 +3114,7 @@ static int mwifiex_pcie_request_irq(struct mwifiex_adapter *adapter)
pr_err("request_irq failed: ret=%d\n", ret);
return -1;
}
+ disable_irq(pdev->irq);
return 0;
}
@@ -3244,7 +3272,7 @@ static struct mwifiex_if_ops pcie_ops = {
.register_dev = mwifiex_register_dev,
.unregister_dev = mwifiex_unregister_dev,
.enable_int = mwifiex_pcie_enable_host_int,
- .disable_int = mwifiex_pcie_disable_host_int_noerr,
+ .disable_int = mwifiex_pcie_disable_host_int,
.process_int_status = mwifiex_process_int_status,
.host_to_card = mwifiex_pcie_host_to_card,
.wakeup = mwifiex_pm_wakeup_card,
--
2.13.0.219.gdb65acc882-goog
next reply other threads:[~2017-05-25 0:11 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-25 0:11 Brian Norris [this message]
2017-05-25 0:11 ` [PATCH 02/14] mwifiex: reunite copy-and-pasted remove/reset code Brian Norris
2017-05-25 0:11 ` [PATCH 03/14] mwifiex: reset interrupt status across device reset Brian Norris
2017-05-25 0:11 ` [PATCH 04/14] mwifiex: pcie: don't allow cmd buffer reuse after reset Brian Norris
2017-05-25 0:11 ` [PATCH 05/14] mwifiex: re-register wiphy across reset Brian Norris
2017-06-01 9:15 ` Kalle Valo
2017-06-01 17:39 ` Brian Norris
2017-06-05 15:54 ` Kalle Valo
2017-06-09 9:03 ` Johannes Berg
2017-06-21 18:27 ` Brian Norris
2017-06-22 13:02 ` Johannes Berg
2017-06-27 20:48 ` Brian Norris
2017-06-28 7:28 ` Johannes Berg
2017-06-29 18:45 ` Brian Norris
2017-07-04 14:10 ` Kalle Valo
2017-06-21 17:48 ` Brian Norris
2017-06-22 12:59 ` Johannes Berg
2017-06-27 19:50 ` Brian Norris
2017-06-28 7:21 ` Johannes Berg
2017-05-25 0:11 ` [PATCH 06/14] mwifiex: don't short-circuit netdev notifiers on interface deletion Brian Norris
2017-05-25 0:11 ` [PATCH 07/14] mwifiex: fixup init_channel_scan_gap error case Brian Norris
2017-05-25 0:11 ` [PATCH 08/14] mwifiex: ensure "disable auto DS" struct is initialized Brian Norris
2017-05-25 0:11 ` [PATCH 09/14] mwifiex: pcie: remove redundant synchronize_irq() Brian Norris
2017-05-25 0:11 ` [PATCH 10/14] mwifiex: pcie: stop masking interrupts in FW downloader Brian Norris
2017-05-25 0:11 ` [PATCH 11/14] mwifiex: utilize netif_tx_{wake,stop}_all_queues() Brian Norris
2017-05-25 0:11 ` [PATCH 12/14] mwifiex: don't open-code ARRAY_SIZE() Brian Norris
2017-05-25 0:11 ` [PATCH 13/14] mwifiex: drop 'add_tail' param from mwifiex_insert_cmd_to_pending_q() Brian Norris
2017-05-25 0:11 ` [PATCH 14/14] mwifiex: pcie: fix whitespace Brian Norris
2017-05-31 17:10 ` [PATCH 01/14] mwifiex: pcie: properly synchronize, disable interrupts in driver callbacks Brian Norris
2017-06-05 11:49 ` Xinming Hu
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