119 lines
4.2 KiB
Diff
119 lines
4.2 KiB
Diff
From ba2727eeebcfa7443347cf6d1370979a821329f0 Mon Sep 17 00:00:00 2001
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Message-Id: <ba2727eeebcfa7443347cf6d1370979a821329f0.1601675151.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Wed, 4 Oct 2017 10:24:23 +0200
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Subject: [PATCH 091/333] pci/switchtec: Don't use completion's wait queue
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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The poll callback is using completion's wait_queue_head_t member and
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puts it in poll_wait() so the poll() caller gets a wakeup after command
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completed. This does not work on RT because we don't have a
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wait_queue_head_t in our completion implementation. Nobody in tree does
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like that in tree so this is the only driver that breaks.
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Instead of using the completion here is waitqueue with a status flag as
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suggested by Logan.
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I don't have the HW so I have no idea if it works as expected, so please
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test it.
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Cc: Kurt Schwemmer <kurt.schwemmer@microsemi.com>
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Cc: Logan Gunthorpe <logang@deltatee.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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drivers/pci/switch/switchtec.c | 22 +++++++++++++---------
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1 file changed, 13 insertions(+), 9 deletions(-)
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diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
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index 291c0074ad6f..a8df847bedee 100644
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--- a/drivers/pci/switch/switchtec.c
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+++ b/drivers/pci/switch/switchtec.c
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@@ -43,10 +43,11 @@ struct switchtec_user {
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enum mrpc_state state;
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- struct completion comp;
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+ wait_queue_head_t cmd_comp;
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struct kref kref;
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struct list_head list;
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+ bool cmd_done;
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u32 cmd;
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u32 status;
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u32 return_code;
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@@ -68,7 +69,7 @@ static struct switchtec_user *stuser_create(struct switchtec_dev *stdev)
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stuser->stdev = stdev;
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kref_init(&stuser->kref);
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INIT_LIST_HEAD(&stuser->list);
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- init_completion(&stuser->comp);
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+ init_waitqueue_head(&stuser->cmd_comp);
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stuser->event_cnt = atomic_read(&stdev->event_cnt);
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dev_dbg(&stdev->dev, "%s: %p\n", __func__, stuser);
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@@ -147,7 +148,7 @@ static int mrpc_queue_cmd(struct switchtec_user *stuser)
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kref_get(&stuser->kref);
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stuser->read_len = sizeof(stuser->data);
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stuser_set_state(stuser, MRPC_QUEUED);
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- reinit_completion(&stuser->comp);
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+ stuser->cmd_done = false;
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list_add_tail(&stuser->list, &stdev->mrpc_queue);
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mrpc_cmd_submit(stdev);
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@@ -184,7 +185,8 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev)
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stuser->read_len);
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out:
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- complete_all(&stuser->comp);
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+ stuser->cmd_done = true;
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+ wake_up_interruptible(&stuser->cmd_comp);
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list_del_init(&stuser->list);
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stuser_put(stuser);
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stdev->mrpc_busy = 0;
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@@ -454,10 +456,11 @@ static ssize_t switchtec_dev_read(struct file *filp, char __user *data,
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mutex_unlock(&stdev->mrpc_mutex);
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if (filp->f_flags & O_NONBLOCK) {
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- if (!try_wait_for_completion(&stuser->comp))
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+ if (!READ_ONCE(stuser->cmd_done))
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return -EAGAIN;
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} else {
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- rc = wait_for_completion_interruptible(&stuser->comp);
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+ rc = wait_event_interruptible(stuser->cmd_comp,
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+ stuser->cmd_done);
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if (rc < 0)
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return rc;
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}
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@@ -505,7 +508,7 @@ static __poll_t switchtec_dev_poll(struct file *filp, poll_table *wait)
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struct switchtec_dev *stdev = stuser->stdev;
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__poll_t ret = 0;
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- poll_wait(filp, &stuser->comp.wait, wait);
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+ poll_wait(filp, &stuser->cmd_comp, wait);
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poll_wait(filp, &stdev->event_wq, wait);
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if (lock_mutex_and_test_alive(stdev))
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@@ -513,7 +516,7 @@ static __poll_t switchtec_dev_poll(struct file *filp, poll_table *wait)
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mutex_unlock(&stdev->mrpc_mutex);
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- if (try_wait_for_completion(&stuser->comp))
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+ if (READ_ONCE(stuser->cmd_done))
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ret |= EPOLLIN | EPOLLRDNORM;
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if (stuser->event_cnt != atomic_read(&stdev->event_cnt))
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@@ -1037,7 +1040,8 @@ static void stdev_kill(struct switchtec_dev *stdev)
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/* Wake up and kill any users waiting on an MRPC request */
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list_for_each_entry_safe(stuser, tmpuser, &stdev->mrpc_queue, list) {
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- complete_all(&stuser->comp);
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+ stuser->cmd_done = true;
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+ wake_up_interruptible(&stuser->cmd_comp);
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list_del_init(&stuser->list);
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stuser_put(stuser);
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}
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--
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2.17.1
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