* [PATCH 1/2] drivers: char: Replace bit operation functions with IDA allocator.
[not found] <cover.1491806760.git.rvarsha016@gmail.com>
@ 2017-04-10 6:58 ` Varsha Rao
2017-04-10 13:45 ` Greg Kroah-Hartman
2017-04-10 6:59 ` [PATCH 2/2] drivers: char: Replace fail_printk with fail_print Varsha Rao
1 sibling, 1 reply; 4+ messages in thread
From: Varsha Rao @ 2017-04-10 6:58 UTC (permalink / raw)
To: Arnd Bergmann, Greg Kroah-Hartman, Matthew Wilcox; +Cc: linux-kernel
Replace bit operation functions with IDA allocator functions. As IDA
allocation is simpler, faster, more space efficient and it generates
small integer IDs which can be used as minor device numbers.
Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
---
drivers/char/misc.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index c9cd1ea..5786281 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -60,7 +60,7 @@ static DEFINE_MUTEX(misc_mtx);
* Assigned numbers, used for dynamic minors
*/
#define DYNAMIC_MINORS 64 /* like dynamic majors */
-static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);
+static DEFINE_IDA(misc_minors_ida);
#ifdef CONFIG_PROC_FS
static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
@@ -193,14 +193,18 @@ int misc_register(struct miscdevice *misc)
mutex_lock(&misc_mtx);
if (is_dynamic) {
- int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS);
+ int i = ida_simple_get(&misc_minors_ida, 0,
+ DYNAMIC_MINORS, GFP_KERNEL);
if (i >= DYNAMIC_MINORS) {
err = -EBUSY;
goto out;
- }
+ } else if (i < 0) {
+ err = i;
+ goto out;
+ } else {
misc->minor = DYNAMIC_MINORS - i - 1;
- set_bit(i, misc_minors);
+ }
} else {
struct miscdevice *c;
@@ -222,7 +226,7 @@ int misc_register(struct miscdevice *misc)
int i = DYNAMIC_MINORS - misc->minor - 1;
if (i < DYNAMIC_MINORS && i >= 0)
- clear_bit(i, misc_minors);
+ ida_simple_remove(&misc_minors_ida, i);
misc->minor = MISC_DYNAMIC_MINOR;
}
err = PTR_ERR(misc->this_device);
@@ -258,7 +262,7 @@ void misc_deregister(struct miscdevice *misc)
list_del(&misc->list);
device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
if (i < DYNAMIC_MINORS && i >= 0)
- clear_bit(i, misc_minors);
+ ida_simple_remove(&misc_minors_ida, i);
mutex_unlock(&misc_mtx);
}
--
2.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/2] drivers: char: Replace fail_printk with fail_print.
[not found] <cover.1491806760.git.rvarsha016@gmail.com>
2017-04-10 6:58 ` [PATCH 1/2] drivers: char: Replace bit operation functions with IDA allocator Varsha Rao
@ 2017-04-10 6:59 ` Varsha Rao
2017-04-10 13:43 ` Greg Kroah-Hartman
1 sibling, 1 reply; 4+ messages in thread
From: Varsha Rao @ 2017-04-10 6:59 UTC (permalink / raw)
To: Arnd Bergmann, Greg Kroah-Hartman, Matthew Wilcox; +Cc: linux-kernel
As printk is no longer used here, rename the label fail_printk as
fail_print.
Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
---
drivers/char/misc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 5786281..0fed477 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -293,11 +293,11 @@ static int __init misc_init(void)
err = -EIO;
if (register_chrdev(MISC_MAJOR, "misc", &misc_fops))
- goto fail_printk;
+ goto fail_print;
misc_class->devnode = misc_devnode;
return 0;
-fail_printk:
+fail_print:
pr_err("unable to get major %d for misc devices\n", MISC_MAJOR);
class_destroy(misc_class);
fail_remove:
--
2.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread