[PATCH] convert /proc/devices to use seq_file interface
A Christoph suggested that the /proc/devices file be converted to use the seq_file interface. This patch does that. I've obxerved one or two installation that had sufficiently large sans that they overran the 4k limit on /proc/devices. Signed-off-by: Neil Horman <nhorman@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Neil Horman
Linus Torvalds
parent
faf3a98918
commit
7170be5f58
4 changed files with 320 additions and 53 deletions
106
block/genhd.c
106
block/genhd.c
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@ -38,34 +38,100 @@ static inline int major_to_index(int major)
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return major % MAX_PROBE_HASH;
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}
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#ifdef CONFIG_PROC_FS
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/* get block device names in somewhat random order */
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int get_blkdev_list(char *p, int used)
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struct blkdev_info {
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int index;
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struct blk_major_name *bd;
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};
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/*
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* iterate over a list of blkdev_info structures. allows
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* the major_names array to be iterated over from outside this file
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* must be called with the block_subsys_sem held
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*/
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void *get_next_blkdev(void *dev)
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{
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struct blkdev_info *info;
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if (dev == NULL) {
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info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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goto out;
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info->index=0;
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info->bd = major_names[info->index];
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if (info->bd)
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goto out;
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} else {
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info = dev;
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}
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while (info->index < ARRAY_SIZE(major_names)) {
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if (info->bd)
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info->bd = info->bd->next;
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if (info->bd)
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goto out;
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/*
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* No devices on this chain, move to the next
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*/
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info->index++;
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info->bd = (info->index < ARRAY_SIZE(major_names)) ?
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major_names[info->index] : NULL;
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if (info->bd)
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goto out;
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}
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out:
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return info;
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}
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void *acquire_blkdev_list(void)
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{
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down(&block_subsys_sem);
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return get_next_blkdev(NULL);
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}
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void release_blkdev_list(void *dev)
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{
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up(&block_subsys_sem);
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kfree(dev);
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}
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/*
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* Count the number of records in the blkdev_list.
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* must be called with the block_subsys_sem held
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*/
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int count_blkdev_list(void)
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{
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struct blk_major_name *n;
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int i, len;
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int i, count;
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len = snprintf(p, (PAGE_SIZE-used), "\nBlock devices:\n");
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count = 0;
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down(&block_subsys_sem);
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for (i = 0; i < ARRAY_SIZE(major_names); i++) {
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for (n = major_names[i]; n; n = n->next) {
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/*
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* If the curent string plus the 5 extra characters
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* in the line would run us off the page, then we're done
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*/
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if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE)
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goto page_full;
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len += sprintf(p+len, "%3d %s\n",
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n->major, n->name);
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}
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for (n = major_names[i]; n; n = n->next)
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count++;
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}
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page_full:
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up(&block_subsys_sem);
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return len;
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return count;
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}
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#endif
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/*
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* extract the major and name values from a blkdev_info struct
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* passed in as a void to *dev. Must be called with
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* block_subsys_sem held
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*/
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int get_blkdev_info(void *dev, int *major, char **name)
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{
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struct blkdev_info *info = dev;
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if (info->bd == NULL)
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return 1;
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*major = info->bd->major;
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*name = info->bd->name;
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return 0;
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}
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int register_blkdev(unsigned int major, const char *name)
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{
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@ -35,7 +35,7 @@ static struct char_device_struct {
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unsigned int major;
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unsigned int baseminor;
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int minorct;
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const char *name;
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char name[64];
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struct file_operations *fops;
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struct cdev *cdev; /* will die */
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} *chrdevs[MAX_PROBE_HASH];
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@ -46,34 +46,84 @@ static inline int major_to_index(int major)
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return major % MAX_PROBE_HASH;
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}
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/* get char device names in somewhat random order */
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int get_chrdev_list(char *page)
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struct chrdev_info {
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int index;
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struct char_device_struct *cd;
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};
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void *get_next_chrdev(void *dev)
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{
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struct chrdev_info *info;
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if (dev == NULL) {
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info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (!info)
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goto out;
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info->index=0;
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info->cd = chrdevs[info->index];
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if (info->cd)
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goto out;
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} else {
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info = dev;
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}
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while (info->index < ARRAY_SIZE(chrdevs)) {
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if (info->cd)
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info->cd = info->cd->next;
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if (info->cd)
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goto out;
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/*
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* No devices on this chain, move to the next
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*/
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info->index++;
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info->cd = (info->index < ARRAY_SIZE(chrdevs)) ?
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chrdevs[info->index] : NULL;
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if (info->cd)
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goto out;
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}
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out:
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return info;
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}
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void *acquire_chrdev_list(void)
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{
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down(&chrdevs_lock);
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return get_next_chrdev(NULL);
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}
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void release_chrdev_list(void *dev)
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{
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up(&chrdevs_lock);
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kfree(dev);
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}
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int count_chrdev_list(void)
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{
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struct char_device_struct *cd;
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int i, len;
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int i, count;
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len = sprintf(page, "Character devices:\n");
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count = 0;
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down(&chrdevs_lock);
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for (i = 0; i < ARRAY_SIZE(chrdevs) ; i++) {
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for (cd = chrdevs[i]; cd; cd = cd->next) {
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/*
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* if the current name, plus the 5 extra characters
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* in the device line for this entry
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* would run us off the page, we're done
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*/
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if ((len+strlen(cd->name) + 5) >= PAGE_SIZE)
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goto page_full;
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len += sprintf(page+len, "%3d %s\n",
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cd->major, cd->name);
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}
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for (cd = chrdevs[i]; cd; cd = cd->next)
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count++;
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}
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page_full:
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up(&chrdevs_lock);
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return len;
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return count;
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}
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int get_chrdev_info(void *dev, int *major, char **name)
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{
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struct chrdev_info *info = dev;
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if (info->cd == NULL)
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return 1;
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*major = info->cd->major;
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*name = info->cd->name;
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return 0;
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}
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/*
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@ -121,7 +171,7 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
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cd->major = major;
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cd->baseminor = baseminor;
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cd->minorct = minorct;
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cd->name = name;
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strncpy(cd->name,name, 64);
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i = major_to_index(major);
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@ -20,6 +20,7 @@
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/kernel_stat.h>
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#include <linux/fs.h>
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#include <linux/tty.h>
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#include <linux/string.h>
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#include <linux/mman.h>
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@ -62,7 +63,6 @@
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*/
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extern int get_hardware_list(char *);
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extern int get_stram_list(char *);
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extern int get_chrdev_list(char *);
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extern int get_filesystem_list(char *);
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extern int get_exec_domain_list(char *);
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extern int get_dma_list(char *);
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@ -248,6 +248,154 @@ static int cpuinfo_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &cpuinfo_op);
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}
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enum devinfo_states {
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CHR_HDR,
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CHR_LIST,
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BLK_HDR,
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BLK_LIST,
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DEVINFO_DONE
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};
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struct devinfo_state {
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void *chrdev;
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void *blkdev;
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unsigned int num_records;
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unsigned int cur_record;
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enum devinfo_states state;
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};
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static void *devinfo_start(struct seq_file *f, loff_t *pos)
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{
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struct devinfo_state *info = f->private;
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if (*pos) {
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if ((info) && (*pos <= info->num_records))
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return info;
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return NULL;
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}
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info = kmalloc(sizeof(*info), GFP_KERNEL);
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f->private = info;
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info->chrdev = acquire_chrdev_list();
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info->blkdev = acquire_blkdev_list();
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info->state = CHR_HDR;
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info->num_records = count_chrdev_list();
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info->num_records += count_blkdev_list();
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info->num_records += 2; /* Character and Block headers */
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*pos = 1;
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info->cur_record = *pos;
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return info;
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}
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static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
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{
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int idummy;
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char *ndummy;
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struct devinfo_state *info = f->private;
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switch (info->state) {
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case CHR_HDR:
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info->state = CHR_LIST;
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(*pos)++;
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/*fallthrough*/
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case CHR_LIST:
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if (get_chrdev_info(info->chrdev,&idummy,&ndummy)) {
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/*
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* The character dev list is complete
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*/
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info->state = BLK_HDR;
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} else {
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info->chrdev = get_next_chrdev(info->chrdev);
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}
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(*pos)++;
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break;
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case BLK_HDR:
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info->state = BLK_LIST;
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(*pos)++;
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break;
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case BLK_LIST:
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if (get_blkdev_info(info->blkdev,&idummy,&ndummy)) {
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/*
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* The block dev list is complete
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*/
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info->state = DEVINFO_DONE;
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} else {
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info->blkdev = get_next_blkdev(info->blkdev);
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}
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(*pos)++;
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break;
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case DEVINFO_DONE:
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(*pos)++;
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info->cur_record = *pos;
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info = NULL;
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break;
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default:
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break;
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}
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if (info)
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info->cur_record = *pos;
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return info;
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}
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static void devinfo_stop(struct seq_file *f, void *v)
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{
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struct devinfo_state *info = f->private;
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if (info) {
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release_chrdev_list(info->chrdev);
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release_blkdev_list(info->blkdev);
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f->private = NULL;
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kfree(info);
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}
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}
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static int devinfo_show(struct seq_file *f, void *arg)
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{
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int major;
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char *name;
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struct devinfo_state *info = f->private;
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switch(info->state) {
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case CHR_HDR:
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seq_printf(f,"Character devices:\n");
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/* fallthrough */
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case CHR_LIST:
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if (!get_chrdev_info(info->chrdev,&major,&name))
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seq_printf(f,"%3d %s\n",major,name);
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break;
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case BLK_HDR:
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seq_printf(f,"\nBlock devices:\n");
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/* fallthrough */
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case BLK_LIST:
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if (!get_blkdev_info(info->blkdev,&major,&name))
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seq_printf(f,"%3d %s\n",major,name);
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break;
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default:
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break;
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}
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return 0;
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}
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static struct seq_operations devinfo_op = {
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.start = devinfo_start,
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.next = devinfo_next,
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.stop = devinfo_stop,
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.show = devinfo_show,
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};
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static int devinfo_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &devinfo_op);
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}
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static struct file_operations proc_devinfo_operations = {
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.open = devinfo_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static struct file_operations proc_cpuinfo_operations = {
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.open = cpuinfo_open,
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.read = seq_read,
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@ -450,14 +598,6 @@ static struct file_operations proc_stat_operations = {
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.release = single_release,
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};
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static int devices_read_proc(char *page, char **start, off_t off,
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int count, int *eof, void *data)
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{
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int len = get_chrdev_list(page);
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len += get_blkdev_list(page+len, len);
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return proc_calc_metrics(page, start, off, count, eof, len);
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}
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/*
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* /proc/interrupts
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*/
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@ -582,7 +722,6 @@ void __init proc_misc_init(void)
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#ifdef CONFIG_STRAM_PROC
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{"stram", stram_read_proc},
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#endif
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{"devices", devices_read_proc},
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{"filesystems", filesystems_read_proc},
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{"cmdline", cmdline_read_proc},
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{"locks", locks_read_proc},
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@ -598,6 +737,7 @@ void __init proc_misc_init(void)
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entry = create_proc_entry("kmsg", S_IRUSR, &proc_root);
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if (entry)
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entry->proc_fops = &proc_kmsg_operations;
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create_seq_entry("devices", 0, &proc_devinfo_operations);
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create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations);
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create_seq_entry("partitions", 0, &proc_partitions_operations);
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create_seq_entry("stat", 0, &proc_stat_operations);
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@ -1383,6 +1383,12 @@ extern int register_chrdev(unsigned int, const char *,
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extern int unregister_chrdev(unsigned int, const char *);
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extern void unregister_chrdev_region(dev_t, unsigned);
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extern int chrdev_open(struct inode *, struct file *);
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extern int get_chrdev_list(char *);
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extern void *acquire_chrdev_list(void);
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extern int count_chrdev_list(void);
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extern void *get_next_chrdev(void *);
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extern int get_chrdev_info(void *, int *, char **);
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extern void release_chrdev_list(void *);
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/* fs/block_dev.c */
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#define BDEVNAME_SIZE 32 /* Largest string for a blockdev identifier */
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@ -1391,6 +1397,11 @@ extern const char *bdevname(struct block_device *bdev, char *buffer);
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extern struct block_device *lookup_bdev(const char *);
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extern struct block_device *open_bdev_excl(const char *, int, void *);
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extern void close_bdev_excl(struct block_device *);
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extern void *acquire_blkdev_list(void);
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extern int count_blkdev_list(void);
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extern void *get_next_blkdev(void *);
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extern int get_blkdev_info(void *, int *, char **);
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extern void release_blkdev_list(void *);
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extern void init_special_inode(struct inode *, umode_t, dev_t);
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