mem_class: use minor as index instead of searching the array

Declare the device list with the minor numbers as the index, which saves us from
searching for a matching list entry. Remove old devfs permissions declaration.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 40 insertions, 42 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 645237bda682..bed3503184e4 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -864,71 +864,67 @@ static const struct file_operations kmsg_fops = {
         .write =        kmsg_write,
 };
 
-static const struct {
-        unsigned int            minor;
-        char                    *name;
-        umode_t                 mode;
-        const struct file_operations    *fops;
-        struct backing_dev_info *dev_info;
-} devlist[] = { /* list of minor devices */
-        {1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops,
-                &directly_mappable_cdev_bdi},
+static const struct memdev {
+        const char *name;
+        const struct file_operations *fops;
+        struct backing_dev_info *dev_info;
+} devlist[] = {
+        [ 1] = { "mem", &mem_fops, &directly_mappable_cdev_bdi },
 #ifdef CONFIG_DEVKMEM
-        {2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops,
-                &directly_mappable_cdev_bdi},
+        [ 2] = { "kmem", &kmem_fops, &directly_mappable_cdev_bdi },
 #endif
-        {3, "null",    S_IRUGO | S_IWUGO,           &null_fops, NULL},
+        [ 3] = {"null", &null_fops, NULL },
 #ifdef CONFIG_DEVPORT
-        {4, "port",    S_IRUSR | S_IWUSR | S_IRGRP, &port_fops, NULL},
+        [ 4] = { "port", &port_fops, NULL },
 #endif
-        {5, "zero",    S_IRUGO | S_IWUGO,           &zero_fops, &zero_bdi},
-        {7, "full",    S_IRUGO | S_IWUGO,           &full_fops, NULL},
-        {8, "random",  S_IRUGO | S_IWUSR,           &random_fops, NULL},
-        {9, "urandom", S_IRUGO | S_IWUSR,           &urandom_fops, NULL},
-        {11,"kmsg",    S_IRUGO | S_IWUSR,           &kmsg_fops, NULL},
+        [ 5] = { "zero", &zero_fops, &zero_bdi },
+        [ 6] = { "full", &full_fops, NULL },
+        [ 7] = { "random", &random_fops, NULL },
+        [ 9] = { "urandom", &urandom_fops, NULL },
+        [11] = { "kmsg", &kmsg_fops, NULL },
 #ifdef CONFIG_CRASH_DUMP
-        {12,"oldmem",    S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops, NULL},
+        [12] = { "oldmem", &oldmem_fops, NULL },
 #endif
 };
 
 static int memory_open(struct inode *inode, struct file *filp)
 {
-        int ret = 0;
-        int i;
+        int minor;
+        const struct memdev *dev;
+        int ret = -ENXIO;
 
         lock_kernel();
 
-        for (i = 0; i < ARRAY_SIZE(devlist); i++) {
-                if (devlist[i].minor == iminor(inode)) {
-                        filp->f_op = devlist[i].fops;
-                        if (devlist[i].dev_info) {
-                                filp->f_mapping->backing_dev_info =
-                                        devlist[i].dev_info;
-                        }
+        minor = iminor(inode);
+        if (minor >= ARRAY_SIZE(devlist))
+                goto out;
 
-                        break;
-                }
-        }
+        dev = &devlist[minor];
+        if (!dev->fops)
+                goto out;
 
-        if (i == ARRAY_SIZE(devlist))
-                ret = -ENXIO;
-        else
-                if (filp->f_op && filp->f_op->open)
-                        ret = filp->f_op->open(inode, filp);
+        filp->f_op = dev->fops;
+        if (dev->dev_info)
+                filp->f_mapping->backing_dev_info = dev->dev_info;
 
+        if (dev->fops->open)
+                ret = dev->fops->open(inode, filp);
+        else
+                ret = 0;
+out:
         unlock_kernel();
         return ret;
 }
 
 static const struct file_operations memory_fops = {
-        .open           = memory_open,  /* just a selector for the real open */
+        .open           = memory_open,
 };
 
 static struct class *mem_class;
 
 static int __init chr_dev_init(void)
 {
-        int i;
+        int minor;
         int err;
 
         err = bdi_init(&zero_bdi);
@@ -939,10 +935,12 @@ static int __init chr_dev_init(void)
                 printk("unable to get major %d for memory devs\n", MEM_MAJOR);
 
         mem_class = class_create(THIS_MODULE, "mem");
-        for (i = 0; i < ARRAY_SIZE(devlist); i++)
-                device_create(mem_class, NULL,
-                              MKDEV(MEM_MAJOR, devlist[i].minor), NULL,
-                              devlist[i].name);
+        for (minor = 1; minor < ARRAY_SIZE(devlist); minor++) {
+                if (!devlist[minor].name)
+                        continue;
+                device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
+                              NULL, devlist[minor].name);
+        }
 
         return 0;
 }