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

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Message-ID: <ZBNDJwFHE3vIFS3+@khadija-virtual-machine>
Date:   Thu, 16 Mar 2023 21:26:15 +0500
From:   Khadija Kamran <kamrankhadijadj@...il.com>
To:     outreachy@...ts.linux.dev
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH v6] staging: axis-fifo: initialize timeouts in init only

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@...uxfoundation.org>
Signed-off-by: Khadija Kamran <kamrankhadijadj@...il.com>
---

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