[PATCH linux dev-4.10 v2 1/9] drivers: fsi: SBEFIFO: General clean-up
Eddie James
eajames at linux.vnet.ibm.com
Sat Sep 30 08:41:00 AEST 2017
From: "Edward A. James" <eajames at us.ibm.com>
Correct formatting and improve the flow a bit. Remove warnings for
offset in read/write functions, and remove the user pointer verification
since the copy_from/to_user will do that anyway. Correct the include
guards in the header file.
Signed-off-by: Edward A. James <eajames at us.ibm.com>
---
drivers/fsi/fsi-sbefifo.c | 207 +++++++++++++++++++++++++-------------------
include/linux/fsi-sbefifo.h | 6 +-
2 files changed, 119 insertions(+), 94 deletions(-)
diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
index 1c37ff7..a4cd353 100644
--- a/drivers/fsi/fsi-sbefifo.c
+++ b/drivers/fsi/fsi-sbefifo.c
@@ -11,20 +11,27 @@
* GNU General Public License for more details.
*/
-#include <linux/delay.h>
+#include <linux/device.h>
#include <linux/errno.h>
-#include <linux/idr.h>
+#include <linux/fs.h>
#include <linux/fsi.h>
+#include <linux/fsi-sbefifo.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/kref.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/uaccess.h>
+#include <linux/wait.h>
/*
* The SBEFIFO is a pipe-like FSI device for communicating with
@@ -44,6 +51,8 @@
#define SBEFIFO_EOT_MAGIC 0xffffffff
#define SBEFIFO_EOT_ACK 0x14
+#define SBEFIFO_RESCHEDULE msecs_to_jiffies(500)
+
struct sbefifo {
struct timer_list poll_timer;
struct fsi_device *fsi_dev;
@@ -94,7 +103,7 @@ struct sbefifo_client {
static int sbefifo_inw(struct sbefifo *sbefifo, int reg, u32 *word)
{
int rc;
- u32 raw_word;
+ __be32 raw_word;
rc = fsi_device_read(sbefifo->fsi_dev, reg, &raw_word,
sizeof(raw_word));
@@ -102,17 +111,19 @@ static int sbefifo_inw(struct sbefifo *sbefifo, int reg, u32 *word)
return rc;
*word = be32_to_cpu(raw_word);
+
return 0;
}
static int sbefifo_outw(struct sbefifo *sbefifo, int reg, u32 word)
{
- u32 raw_word = cpu_to_be32(word);
+ __be32 raw_word = cpu_to_be32(word);
return fsi_device_write(sbefifo->fsi_dev, reg, &raw_word,
sizeof(raw_word));
}
+/* Don't flip endianness of data to/from FIFO, just pass through. */
static int sbefifo_readw(struct sbefifo *sbefifo, u32 *word)
{
return fsi_device_read(sbefifo->fsi_dev, SBEFIFO_DWN, word,
@@ -136,7 +147,7 @@ static int sbefifo_ack_eot(struct sbefifo *sbefifo)
return ret;
return sbefifo_outw(sbefifo, SBEFIFO_DWN | SBEFIFO_EOT_ACK,
- SBEFIFO_EOT_MAGIC);
+ SBEFIFO_EOT_MAGIC);
}
static size_t sbefifo_dev_nwreadable(u32 sts)
@@ -210,6 +221,7 @@ static bool sbefifo_buf_readnb(struct sbefifo_buf *buf, size_t n)
rpos = buf->buf;
WRITE_ONCE(buf->rpos, rpos);
+
return rpos == wpos;
}
@@ -229,14 +241,14 @@ static bool sbefifo_buf_wrotenb(struct sbefifo_buf *buf, size_t n)
set_bit(SBEFIFO_BUF_FULL, &buf->flags);
WRITE_ONCE(buf->wpos, wpos);
+
return rpos == wpos;
}
static void sbefifo_free(struct kref *kref)
{
- struct sbefifo *sbefifo;
+ struct sbefifo *sbefifo = container_of(kref, struct sbefifo, kref);
- sbefifo = container_of(kref, struct sbefifo, kref);
kfree(sbefifo);
}
@@ -267,21 +279,12 @@ static struct sbefifo_xfr *sbefifo_enq_xfr(struct sbefifo_client *client)
return xfr;
}
-static struct sbefifo_xfr *sbefifo_client_next_xfr(
- struct sbefifo_client *client)
-{
- if (list_empty(&client->xfrs))
- return NULL;
-
- return container_of(client->xfrs.next, struct sbefifo_xfr,
- client);
-}
-
static bool sbefifo_xfr_rsp_pending(struct sbefifo_client *client)
{
- struct sbefifo_xfr *xfr;
+ struct sbefifo_xfr *xfr = list_first_entry_or_null(&client->xfrs,
+ struct sbefifo_xfr,
+ client);
- xfr = sbefifo_client_next_xfr(client);
if (xfr && test_bit(SBEFIFO_XFR_RESP_PENDING, &xfr->flags))
return true;
@@ -349,6 +352,7 @@ static struct sbefifo_xfr *sbefifo_next_xfr(struct sbefifo *sbefifo)
kfree(xfr);
continue;
}
+
return xfr;
}
@@ -370,7 +374,7 @@ static void sbefifo_poll_timer(unsigned long data)
spin_lock(&sbefifo->lock);
xfr = list_first_entry_or_null(&sbefifo->xfrs, struct sbefifo_xfr,
- xfrs);
+ xfrs);
if (!xfr)
goto out_unlock;
@@ -388,8 +392,7 @@ static void sbefifo_poll_timer(unsigned long data)
/* Drain the write buffer. */
while ((bufn = sbefifo_buf_nbreadable(wbuf))) {
- ret = sbefifo_inw(sbefifo, SBEFIFO_UP | SBEFIFO_STS,
- &sts);
+ ret = sbefifo_inw(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &sts);
if (ret)
goto out;
@@ -397,7 +400,7 @@ static void sbefifo_poll_timer(unsigned long data)
if (devn == 0) {
/* No open slot for write. Reschedule. */
sbefifo->poll_timer.expires = jiffies +
- msecs_to_jiffies(500);
+ SBEFIFO_RESCHEDULE;
add_timer(&sbefifo->poll_timer);
goto out_unlock;
}
@@ -414,9 +417,8 @@ static void sbefifo_poll_timer(unsigned long data)
/* Send EOT if the writer is finished. */
if (test_and_clear_bit(SBEFIFO_XFR_WRITE_DONE, &xfr->flags)) {
- ret = sbefifo_outw(sbefifo,
- SBEFIFO_UP | SBEFIFO_EOT_RAISE,
- SBEFIFO_EOT_MAGIC);
+ ret = sbefifo_outw(sbefifo, SBEFIFO_UP | SBEFIFO_EOT_RAISE,
+ SBEFIFO_EOT_MAGIC);
if (ret)
goto out;
@@ -438,7 +440,7 @@ static void sbefifo_poll_timer(unsigned long data)
if (devn == 0) {
/* No data yet. Reschedule. */
sbefifo->poll_timer.expires = jiffies +
- msecs_to_jiffies(500);
+ SBEFIFO_RESCHEDULE;
add_timer(&sbefifo->poll_timer);
goto out_unlock;
}
@@ -466,7 +468,7 @@ static void sbefifo_poll_timer(unsigned long data)
set_bit(SBEFIFO_XFR_COMPLETE, &xfr->flags);
list_del(&xfr->xfrs);
if (unlikely(test_bit(SBEFIFO_XFR_CANCEL,
- &xfr->flags)))
+ &xfr->flags)))
kfree(xfr);
break;
}
@@ -476,7 +478,7 @@ static void sbefifo_poll_timer(unsigned long data)
if (unlikely(ret)) {
sbefifo->rc = ret;
dev_err(&sbefifo->fsi_dev->dev,
- "Fatal bus access failure: %d\n", ret);
+ "Fatal bus access failure: %d\n", ret);
list_for_each_entry(xfr, &sbefifo->xfrs, xfrs)
kfree(xfr);
INIT_LIST_HEAD(&sbefifo->xfrs);
@@ -497,7 +499,7 @@ static void sbefifo_poll_timer(unsigned long data)
static int sbefifo_open(struct inode *inode, struct file *file)
{
struct sbefifo *sbefifo = container_of(file->private_data,
- struct sbefifo, mdev);
+ struct sbefifo, mdev);
struct sbefifo_client *client;
int ret;
@@ -535,6 +537,16 @@ static unsigned int sbefifo_poll(struct file *file, poll_table *wait)
return mask;
}
+static bool sbefifo_read_ready(struct sbefifo *sbefifo,
+ struct sbefifo_client *client, size_t *n,
+ size_t *ret)
+{
+ *n = sbefifo_buf_nbreadable(&client->rbuf);
+ *ret = READ_ONCE(sbefifo->rc);
+
+ return *ret || *n;
+}
+
static ssize_t sbefifo_read_common(struct sbefifo_client *client,
char __user *ubuf, char *kbuf, size_t len)
{
@@ -551,30 +563,37 @@ static ssize_t sbefifo_read_common(struct sbefifo_client *client,
sbefifo_get_client(client);
if (wait_event_interruptible(sbefifo->wait,
- (ret = READ_ONCE(sbefifo->rc)) ||
- (n = sbefifo_buf_nbreadable(
- &client->rbuf)))) {
- sbefifo_put_client(client);
- return -ERESTARTSYS;
+ sbefifo_read_ready(sbefifo, client,
+ &n, &ret))) {
+ ret = -ERESTARTSYS;
+ goto out;
}
+
if (ret) {
INIT_LIST_HEAD(&client->xfrs);
- sbefifo_put_client(client);
- return ret;
+ goto out;
}
n = min_t(size_t, n, len);
if (ubuf) {
if (copy_to_user(ubuf, READ_ONCE(client->rbuf.rpos), n)) {
- sbefifo_put_client(client);
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
- } else
+ } else {
memcpy(kbuf, READ_ONCE(client->rbuf.rpos), n);
+ }
if (sbefifo_buf_readnb(&client->rbuf, n)) {
- xfr = sbefifo_client_next_xfr(client);
+ xfr = list_first_entry_or_null(&client->xfrs,
+ struct sbefifo_xfr, client);
+ if (!xfr) {
+ /* should be impossible to not have an xfr here */
+ WARN_ONCE(1, "no xfr in queue");
+ goto out;
+ }
+
if (!test_bit(SBEFIFO_XFR_COMPLETE, &xfr->flags)) {
/*
* Fill the read buffer back up.
@@ -589,22 +608,31 @@ static ssize_t sbefifo_read_common(struct sbefifo_client *client,
}
}
- sbefifo_put_client(client);
+ ret = n;
- return n;
+out:
+ sbefifo_put_client(client);
+ return ret;
}
-static ssize_t sbefifo_read(struct file *file, char __user *buf,
- size_t len, loff_t *offset)
+static ssize_t sbefifo_read(struct file *file, char __user *buf, size_t len,
+ loff_t *offset)
{
struct sbefifo_client *client = file->private_data;
- WARN_ON(*offset);
+ return sbefifo_read_common(client, buf, NULL, len);
+}
- if (!access_ok(VERIFY_WRITE, buf, len))
- return -EFAULT;
+static bool sbefifo_write_ready(struct sbefifo *sbefifo,
+ struct sbefifo_xfr *xfr,
+ struct sbefifo_client *client, size_t *n)
+{
+ struct sbefifo_xfr *next = list_first_entry_or_null(&client->xfrs,
+ struct sbefifo_xfr,
+ client);
- return sbefifo_read_common(client, buf, NULL, len);
+ *n = sbefifo_buf_nbwriteable(&client->wbuf);
+ return READ_ONCE(sbefifo->rc) || (next == xfr && *n);
}
static ssize_t sbefifo_write_common(struct sbefifo_client *client,
@@ -612,6 +640,7 @@ static ssize_t sbefifo_write_common(struct sbefifo_client *client,
size_t len)
{
struct sbefifo *sbefifo = client->dev;
+ struct sbefifo_buf *wbuf = &client->wbuf;
struct sbefifo_xfr *xfr;
ssize_t ret = 0;
size_t n;
@@ -622,24 +651,26 @@ static ssize_t sbefifo_write_common(struct sbefifo_client *client,
if (!len)
return 0;
- n = sbefifo_buf_nbwriteable(&client->wbuf);
+ sbefifo_get_client(client);
+ n = sbefifo_buf_nbwriteable(wbuf);
spin_lock_irq(&sbefifo->lock);
- xfr = sbefifo_next_xfr(sbefifo);
+ xfr = sbefifo_next_xfr(sbefifo); /* next xfr to be executed */
if ((client->f_flags & O_NONBLOCK) && xfr && n < len) {
spin_unlock_irq(&sbefifo->lock);
- return -EAGAIN;
+ ret = -EAGAIN;
+ goto out;
}
- xfr = sbefifo_enq_xfr(client);
+ xfr = sbefifo_enq_xfr(client); /* this xfr queued up */
if (!xfr) {
spin_unlock_irq(&sbefifo->lock);
- return -ENOMEM;
+ ret = PTR_ERR(xfr);
+ goto out;
}
- spin_unlock_irq(&sbefifo->lock);
- sbefifo_get_client(client);
+ spin_unlock_irq(&sbefifo->lock);
/*
* Partial writes are not really allowed in that EOT is sent exactly
@@ -647,49 +678,47 @@ static ssize_t sbefifo_write_common(struct sbefifo_client *client,
*/
while (len) {
if (wait_event_interruptible(sbefifo->wait,
- READ_ONCE(sbefifo->rc) ||
- (sbefifo_client_next_xfr(client) == xfr &&
- (n = sbefifo_buf_nbwriteable(
- &client->wbuf))))) {
+ sbefifo_write_ready(sbefifo, xfr,
+ client,
+ &n))) {
set_bit(SBEFIFO_XFR_CANCEL, &xfr->flags);
sbefifo_get(sbefifo);
if (mod_timer(&sbefifo->poll_timer, jiffies))
sbefifo_put(sbefifo);
-
- sbefifo_put_client(client);
- return -ERESTARTSYS;
+ ret = -ERESTARTSYS;
+ goto out;
}
+
if (sbefifo->rc) {
INIT_LIST_HEAD(&client->xfrs);
- sbefifo_put_client(client);
- return sbefifo->rc;
+ ret = sbefifo->rc;
+ goto out;
}
n = min_t(size_t, n, len);
if (ubuf) {
- if (copy_from_user(READ_ONCE(client->wbuf.wpos), ubuf,
- n)) {
+ if (copy_from_user(READ_ONCE(wbuf->wpos), ubuf, n)) {
set_bit(SBEFIFO_XFR_CANCEL, &xfr->flags);
sbefifo_get(sbefifo);
if (mod_timer(&sbefifo->poll_timer, jiffies))
sbefifo_put(sbefifo);
- sbefifo_put_client(client);
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
ubuf += n;
} else {
- memcpy(READ_ONCE(client->wbuf.wpos), kbuf, n);
+ memcpy(READ_ONCE(wbuf->wpos), kbuf, n);
kbuf += n;
}
- sbefifo_buf_wrotenb(&client->wbuf, n);
+ sbefifo_buf_wrotenb(wbuf, n);
len -= n;
ret += n;
- /* set flag before starting the worker, as it may run through
- * and check the flag before we exit this loop!
+ /* Set this before starting timer to avoid race condition on
+ * this flag with the timer function writer.
*/
if (!len)
set_bit(SBEFIFO_XFR_WRITE_DONE, &xfr->flags);
@@ -702,21 +731,16 @@ static ssize_t sbefifo_write_common(struct sbefifo_client *client,
sbefifo_put(sbefifo);
}
+out:
sbefifo_put_client(client);
-
return ret;
}
static ssize_t sbefifo_write(struct file *file, const char __user *buf,
- size_t len, loff_t *offset)
+ size_t len, loff_t *offset)
{
struct sbefifo_client *client = file->private_data;
- WARN_ON(*offset);
-
- if (!access_ok(VERIFY_READ, buf, len))
- return -EFAULT;
-
return sbefifo_write_common(client, buf, NULL, len);
}
@@ -802,29 +826,27 @@ static int sbefifo_probe(struct device *dev)
u32 sts;
int ret, child_idx = 0;
- dev_dbg(dev, "Found sbefifo device\n");
sbefifo = kzalloc(sizeof(*sbefifo), GFP_KERNEL);
if (!sbefifo)
return -ENOMEM;
sbefifo->fsi_dev = fsi_dev;
- ret = sbefifo_inw(sbefifo,
- SBEFIFO_UP | SBEFIFO_STS, &sts);
+ ret = sbefifo_inw(sbefifo, SBEFIFO_UP | SBEFIFO_STS, &sts);
if (ret)
return ret;
+
if (!(sts & SBEFIFO_EMPTY)) {
- dev_err(&sbefifo->fsi_dev->dev,
- "Found data in upstream fifo\n");
+ dev_err(dev, "Found data in upstream fifo\n");
return -EIO;
}
ret = sbefifo_inw(sbefifo, SBEFIFO_DWN | SBEFIFO_STS, &sts);
if (ret)
return ret;
+
if (!(sts & SBEFIFO_EMPTY)) {
- dev_err(&sbefifo->fsi_dev->dev,
- "Found data in downstream fifo\n");
+ dev_err(dev, "found data in downstream fifo\n");
return -EIO;
}
@@ -837,13 +859,13 @@ static int sbefifo_probe(struct device *dev)
sbefifo->idx = ida_simple_get(&sbefifo_ida, 1, INT_MAX, GFP_KERNEL);
snprintf(sbefifo->name, sizeof(sbefifo->name), "sbefifo%d",
- sbefifo->idx);
+ sbefifo->idx);
init_waitqueue_head(&sbefifo->wait);
INIT_LIST_HEAD(&sbefifo->xfrs);
/* This bit of silicon doesn't offer any interrupts... */
setup_timer(&sbefifo->poll_timer, sbefifo_poll_timer,
- (unsigned long)sbefifo);
+ (unsigned long)sbefifo);
if (dev->of_node) {
/* create platform devs for dts child nodes (occ, etc) */
@@ -852,7 +874,7 @@ static int sbefifo_probe(struct device *dev)
sbefifo->name, child_idx++);
child = of_platform_device_create(np, child_name, dev);
if (!child)
- dev_warn(&sbefifo->fsi_dev->dev,
+ dev_warn(dev,
"failed to create child node dev\n");
}
}
@@ -922,10 +944,13 @@ static int sbefifo_init(void)
static void sbefifo_exit(void)
{
fsi_driver_unregister(&sbefifo_drv);
+
+ ida_destroy(&sbefifo_ida);
}
module_init(sbefifo_init);
module_exit(sbefifo_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Brad Bishop <bradleyb at fuzziesquirrel.com>");
-MODULE_DESCRIPTION("Linux device interface to the POWER self boot engine");
+MODULE_AUTHOR("Eddie James <eajames at linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("Linux device interface to the POWER Self Boot Engine");
diff --git a/include/linux/fsi-sbefifo.h b/include/linux/fsi-sbefifo.h
index 1b46c63..8e55891 100644
--- a/include/linux/fsi-sbefifo.h
+++ b/include/linux/fsi-sbefifo.h
@@ -13,8 +13,8 @@
* GNU General Public License for more details.
*/
-#ifndef __FSI_SBEFIFO_H__
-#define __FSI_SBEFIFO_H__
+#ifndef LINUX_FSI_SBEFIFO_H
+#define LINUX_FSI_SBEFIFO_H
struct device;
struct sbefifo_client;
@@ -27,4 +27,4 @@ extern int sbefifo_drv_write(struct sbefifo_client *client, const char *buf,
size_t len);
extern void sbefifo_drv_release(struct sbefifo_client *client);
-#endif /* __FSI_SBEFIFO_H__ */
+#endif /* LINUX_FSI_SBEFIFO_H */
--
1.8.3.1
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