[PATCH v6] staging: axis-fifo: initialize timeouts in init only

From: Khadija Kamran
Date: Thu Mar 16 2023 - 12:26:34 EST


Initialize the module parameters, read_timeout and write_timeout once in
init().

Module parameters can only be set once and cannot be modified later, so we
don't need to evaluate them again when passing the parameters to
wait_event_interruptible_timeout().

Convert datatype of {read,write}_timeout from 'int' to 'long int' because
implicit conversion of 'long int' to 'int' in statement
'{read,write}_timeout = MAX_SCHEDULE_TIMEOUT' results in an overflow.

Change format specifier for {read,write}_timeout from %i to %li.

Suggested-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Khadija Kamran <kamrankhadijadj@xxxxxxxxx>
---

Changes in v6:
- Initialize module parameters in init instead of probe function.
- Change the subject and description
- Change format specifiers of module parameters to "%li"

Changes in v5:
- Convert module parameters's datatype from int to long.
- Link to patch:
https://lore.kernel.org/outreachy/ZBMR4s8xyHGqMm72@khadija-virtual-machine/

Changes in v4:
- Initialize timeouts once as suggested by Greg; this automatically
fixes the indentation problems.
- Change the subject and description.
- Link to patch:
https://lore.kernel.org/outreachy/ZA4M3+ZeB1Rl2fbs@khadija-virtual-machine/

Changes in v3:
- Correct grammatical mistakes
- Do not change the second argument's indentation in split lines

Changes in v2:
- Instead of matching alignment to open parenthesis, align second and
the last argument.
- Change the subject and use imperative language.
- Link to patch:
https://lore.kernel.org/outreachy/ZAxNYw2rFQkrdtKl@khadija-virtual-machine/

Link to first patch:
https://lore.kernel.org/outreachy/ZAZSmPpB6fcozGa4@khadija-virtual-machine/

drivers/staging/axis-fifo/axis-fifo.c | 28 ++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/axis-fifo/axis-fifo.c b/drivers/staging/axis-fifo/axis-fifo.c
index dfd2b357f484..0a85ea667a1b 100644
--- a/drivers/staging/axis-fifo/axis-fifo.c
+++ b/drivers/staging/axis-fifo/axis-fifo.c
@@ -103,17 +103,17 @@
* globals
* ----------------------------
*/
-static int read_timeout = 1000; /* ms to wait before read() times out */
-static int write_timeout = 1000; /* ms to wait before write() times out */
+static long read_timeout = 1000; /* ms to wait before read() times out */
+static long write_timeout = 1000; /* ms to wait before write() times out */

/* ----------------------------
* module command-line arguments
* ----------------------------
*/

-module_param(read_timeout, int, 0444);
+module_param(read_timeout, long, 0444);
MODULE_PARM_DESC(read_timeout, "ms to wait before blocking read() timing out; set to -1 for no timeout");
-module_param(write_timeout, int, 0444);
+module_param(write_timeout, long, 0444);
MODULE_PARM_DESC(write_timeout, "ms to wait before blocking write() timing out; set to -1 for no timeout");

/* ----------------------------
@@ -384,9 +384,7 @@ static ssize_t axis_fifo_read(struct file *f, char __user *buf,
mutex_lock(&fifo->read_lock);
ret = wait_event_interruptible_timeout(fifo->read_queue,
ioread32(fifo->base_addr + XLLF_RDFO_OFFSET),
- (read_timeout >= 0) ?
- msecs_to_jiffies(read_timeout) :
- MAX_SCHEDULE_TIMEOUT);
+ read_timeout);

if (ret <= 0) {
if (ret == 0) {
@@ -528,9 +526,7 @@ static ssize_t axis_fifo_write(struct file *f, const char __user *buf,
ret = wait_event_interruptible_timeout(fifo->write_queue,
ioread32(fifo->base_addr + XLLF_TDFV_OFFSET)
>= words_to_write,
- (write_timeout >= 0) ?
- msecs_to_jiffies(write_timeout) :
- MAX_SCHEDULE_TIMEOUT);
+ write_timeout);

if (ret <= 0) {
if (ret == 0) {
@@ -948,7 +944,17 @@ static struct platform_driver axis_fifo_driver = {

static int __init axis_fifo_init(void)
{
- pr_info("axis-fifo driver loaded with parameters read_timeout = %i, write_timeout = %i\n",
+ if (read_timeout >= 0)
+ read_timeout = msecs_to_jiffies(read_timeout);
+ else
+ read_timeout = MAX_SCHEDULE_TIMEOUT;
+
+ if (write_timeout >= 0)
+ write_timeout = msecs_to_jiffies(write_timeout);
+ else
+ write_timeout = MAX_SCHEDULE_TIMEOUT;
+
+ pr_info("axis-fifo driver loaded with parameters read_timeout = %li, write_timeout = %li\n",
read_timeout, write_timeout);
return platform_driver_register(&axis_fifo_driver);
}
--
2.34.1