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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0091-pci-switchtec-Don-t-use-completion-s-wait-queue.patch | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/debian/patches-rt/0091-pci-switchtec-Don-t-use-completion-s-wait-queue.patch b/debian/patches-rt/0091-pci-switchtec-Don-t-use-completion-s-wait-queue.patch new file mode 100644 index 000000000..c42b306c1 --- /dev/null +++ b/debian/patches-rt/0091-pci-switchtec-Don-t-use-completion-s-wait-queue.patch @@ -0,0 +1,115 @@ +From aec60cbb460a43de9b530e8b08d24c032292c210 Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Wed, 4 Oct 2017 10:24:23 +0200 +Subject: [PATCH 091/347] pci/switchtec: Don't use completion's wait queue +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +The poll callback is using completion's wait_queue_head_t member and +puts it in poll_wait() so the poll() caller gets a wakeup after command +completed. This does not work on RT because we don't have a +wait_queue_head_t in our completion implementation. Nobody in tree does +like that in tree so this is the only driver that breaks. + +Instead of using the completion here is waitqueue with a status flag as +suggested by Logan. + +I don't have the HW so I have no idea if it works as expected, so please +test it. + +Cc: Kurt Schwemmer <kurt.schwemmer@microsemi.com> +Cc: Logan Gunthorpe <logang@deltatee.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/pci/switch/switchtec.c | 22 +++++++++++++--------- + 1 file changed, 13 insertions(+), 9 deletions(-) + +diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c +index 291c0074ad6f..a8df847bedee 100644 +--- a/drivers/pci/switch/switchtec.c ++++ b/drivers/pci/switch/switchtec.c +@@ -43,10 +43,11 @@ struct switchtec_user { + + enum mrpc_state state; + +- struct completion comp; ++ wait_queue_head_t cmd_comp; + struct kref kref; + struct list_head list; + ++ bool cmd_done; + u32 cmd; + u32 status; + u32 return_code; +@@ -68,7 +69,7 @@ static struct switchtec_user *stuser_create(struct switchtec_dev *stdev) + stuser->stdev = stdev; + kref_init(&stuser->kref); + INIT_LIST_HEAD(&stuser->list); +- init_completion(&stuser->comp); ++ init_waitqueue_head(&stuser->cmd_comp); + stuser->event_cnt = atomic_read(&stdev->event_cnt); + + dev_dbg(&stdev->dev, "%s: %p\n", __func__, stuser); +@@ -147,7 +148,7 @@ static int mrpc_queue_cmd(struct switchtec_user *stuser) + kref_get(&stuser->kref); + stuser->read_len = sizeof(stuser->data); + stuser_set_state(stuser, MRPC_QUEUED); +- reinit_completion(&stuser->comp); ++ stuser->cmd_done = false; + list_add_tail(&stuser->list, &stdev->mrpc_queue); + + mrpc_cmd_submit(stdev); +@@ -184,7 +185,8 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev) + stuser->read_len); + + out: +- complete_all(&stuser->comp); ++ stuser->cmd_done = true; ++ wake_up_interruptible(&stuser->cmd_comp); + list_del_init(&stuser->list); + stuser_put(stuser); + stdev->mrpc_busy = 0; +@@ -454,10 +456,11 @@ static ssize_t switchtec_dev_read(struct file *filp, char __user *data, + mutex_unlock(&stdev->mrpc_mutex); + + if (filp->f_flags & O_NONBLOCK) { +- if (!try_wait_for_completion(&stuser->comp)) ++ if (!READ_ONCE(stuser->cmd_done)) + return -EAGAIN; + } else { +- rc = wait_for_completion_interruptible(&stuser->comp); ++ rc = wait_event_interruptible(stuser->cmd_comp, ++ stuser->cmd_done); + if (rc < 0) + return rc; + } +@@ -505,7 +508,7 @@ static __poll_t switchtec_dev_poll(struct file *filp, poll_table *wait) + struct switchtec_dev *stdev = stuser->stdev; + __poll_t ret = 0; + +- poll_wait(filp, &stuser->comp.wait, wait); ++ poll_wait(filp, &stuser->cmd_comp, wait); + poll_wait(filp, &stdev->event_wq, wait); + + if (lock_mutex_and_test_alive(stdev)) +@@ -513,7 +516,7 @@ static __poll_t switchtec_dev_poll(struct file *filp, poll_table *wait) + + mutex_unlock(&stdev->mrpc_mutex); + +- if (try_wait_for_completion(&stuser->comp)) ++ if (READ_ONCE(stuser->cmd_done)) + ret |= EPOLLIN | EPOLLRDNORM; + + if (stuser->event_cnt != atomic_read(&stdev->event_cnt)) +@@ -1037,7 +1040,8 @@ static void stdev_kill(struct switchtec_dev *stdev) + + /* Wake up and kill any users waiting on an MRPC request */ + list_for_each_entry_safe(stuser, tmpuser, &stdev->mrpc_queue, list) { +- complete_all(&stuser->comp); ++ stuser->cmd_done = true; ++ wake_up_interruptible(&stuser->cmd_comp); + list_del_init(&stuser->list); + stuser_put(stuser); + } +-- +2.36.1 + |