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Commit 9a181c58617134822ae596339dbea076ef9b5cf7

Authored by Arnd Bergmann
1 parent fa0d4c26be
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

uml: kill big kernel lock 

Three uml device drivers still use the big kernel lock,
but all of them can be safely converted to using
a per-driver mutex instead. Most likely this is not
even necessary, so after further review these can
and should be removed as well.

The exec system call no longer requires the BKL either,
so remove it from there, too.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: user-mode-linux-devel@lists.sourceforge.net

Showing 4 changed files with 20 additions and 18 deletions Side-by-side Diff

arch/um/drivers/harddog_kern.c
Diff comments   View file @ 9a181c5
... ... @@ -42,7 +42,7 @@
42 42 #include <linux/miscdevice.h>
43 43 #include <linux/watchdog.h>
44 44 #include <linux/reboot.h>
45   -#include <linux/smp_lock.h>
  45 +#include <linux/mutex.h>
46 46 #include <linux/init.h>
47 47 #include <linux/spinlock.h>
48 48 #include <asm/uaccess.h>
... ... @@ -50,6 +50,7 @@
50 50  
51 51 MODULE_LICENSE("GPL");
52 52  
  53 +static DEFINE_MUTEX(harddog_mutex);
53 54 static DEFINE_SPINLOCK(lock);
54 55 static int timer_alive;
55 56 static int harddog_in_fd = -1;
... ... @@ -66,7 +67,7 @@
66 67 int err = -EBUSY;
67 68 char *sock = NULL;
68 69  
69   - lock_kernel();
  70 + mutex_lock(&harddog_mutex);
70 71 spin_lock(&lock);
71 72 if(timer_alive)
72 73 goto err;
73 74  
... ... @@ -83,11 +84,11 @@
83 84  
84 85 timer_alive = 1;
85 86 spin_unlock(&lock);
86   - unlock_kernel();
  87 + mutex_unlock(&harddog_mutex);
87 88 return nonseekable_open(inode, file);
88 89 err:
89 90 spin_unlock(&lock);
90   - unlock_kernel();
  91 + mutex_unlock(&harddog_mutex);
91 92 return err;
92 93 }
93 94  
94 95  
... ... @@ -153,9 +154,9 @@
153 154 {
154 155 long ret;
155 156  
156   - lock_kernel();
  157 + mutex_lock(&harddog_mutex);
157 158 ret = harddog_ioctl_unlocked(file, cmd, arg);
158   - unlock_kernel();
  159 + mutex_unlock(&harddog_mutex);
159 160  
160 161 return ret;
161 162 }
arch/um/drivers/hostaudio_kern.c
Diff comments   View file @ 9a181c5
... ... @@ -8,7 +8,7 @@
8 8 #include "linux/slab.h"
9 9 #include "linux/sound.h"
10 10 #include "linux/soundcard.h"
11   -#include "linux/smp_lock.h"
  11 +#include "linux/mutex.h"
12 12 #include "asm/uaccess.h"
13 13 #include "init.h"
14 14 #include "os.h"
... ... @@ -67,6 +67,8 @@
67 67  
68 68 #endif
69 69  
  70 +static DEFINE_MUTEX(hostaudio_mutex);
  71 +
70 72 /* /dev/dsp file operations */
71 73  
72 74 static ssize_t hostaudio_read(struct file *file, char __user *buffer,
73 75  
... ... @@ -202,9 +204,9 @@
202 204 w = 1;
203 205  
204 206 kparam_block_sysfs_write(dsp);
205   - lock_kernel();
  207 + mutex_lock(&hostaudio_mutex);
206 208 ret = os_open_file(dsp, of_set_rw(OPENFLAGS(), r, w), 0);
207   - unlock_kernel();
  209 + mutex_unlock(&hostaudio_mutex);
208 210 kparam_unblock_sysfs_write(dsp);
209 211  
210 212 if (ret < 0) {
211 213  
... ... @@ -263,9 +265,9 @@
263 265 w = 1;
264 266  
265 267 kparam_block_sysfs_write(mixer);
266   - lock_kernel();
  268 + mutex_lock(&hostaudio_mutex);
267 269 ret = os_open_file(mixer, of_set_rw(OPENFLAGS(), r, w), 0);
268   - unlock_kernel();
  270 + mutex_unlock(&hostaudio_mutex);
269 271 kparam_unblock_sysfs_write(mixer);
270 272  
271 273 if (ret < 0) {
arch/um/drivers/ubd_kern.c
Diff comments   View file @ 9a181c5
... ... @@ -33,7 +33,7 @@
33 33 #include "linux/mm.h"
34 34 #include "linux/slab.h"
35 35 #include "linux/vmalloc.h"
36   -#include "linux/smp_lock.h"
  36 +#include "linux/mutex.h"
37 37 #include "linux/blkpg.h"
38 38 #include "linux/genhd.h"
39 39 #include "linux/spinlock.h"
... ... @@ -100,6 +100,7 @@
100 100 #define DRIVER_NAME "uml-blkdev"
101 101  
102 102 static DEFINE_MUTEX(ubd_lock);
  103 +static DEFINE_MUTEX(ubd_mutex); /* replaces BKL, might not be needed */
103 104  
104 105 static int ubd_open(struct block_device *bdev, fmode_t mode);
105 106 static int ubd_release(struct gendisk *disk, fmode_t mode);
... ... @@ -1099,7 +1100,7 @@
1099 1100 struct ubd *ubd_dev = disk->private_data;
1100 1101 int err = 0;
1101 1102  
1102   - lock_kernel();
  1103 + mutex_lock(&ubd_mutex);
1103 1104 if(ubd_dev->count == 0){
1104 1105 err = ubd_open_dev(ubd_dev);
1105 1106 if(err){
... ... @@ -1118,7 +1119,7 @@
1118 1119 err = -EROFS;
1119 1120 }*/
1120 1121 out:
1121   - unlock_kernel();
  1122 + mutex_unlock(&ubd_mutex);
1122 1123 return err;
1123 1124 }
1124 1125  
1125 1126  
... ... @@ -1126,10 +1127,10 @@
1126 1127 {
1127 1128 struct ubd *ubd_dev = disk->private_data;
1128 1129  
1129   - lock_kernel();
  1130 + mutex_lock(&ubd_mutex);
1130 1131 if(--ubd_dev->count == 0)
1131 1132 ubd_close_dev(ubd_dev);
1132   - unlock_kernel();
  1133 + mutex_unlock(&ubd_mutex);
1133 1134 return 0;
1134 1135 }
1135 1136  
arch/um/kernel/exec.c
Diff comments   View file @ 9a181c5
... ... @@ -78,14 +78,12 @@
78 78 long error;
79 79 char *filename;
80 80  
81   - lock_kernel();
82 81 filename = getname(file);
83 82 error = PTR_ERR(filename);
84 83 if (IS_ERR(filename)) goto out;
85 84 error = execve1(filename, argv, env);
86 85 putname(filename);
87 86 out:
88   - unlock_kernel();
89 87 return error;
90 88 }