This patch to 2.5.44 make /proc/swaps use seq_file.
Question: is any locking needed here?
The previous code didn't use any locking.
Any other feedback on it?
Thanks,
~Randy
~~~
--- ./fs/proc/proc_misc.c.swaps Fri Oct 18 21:01:14 2002
+++ ./fs/proc/proc_misc.c Mon Oct 21 20:11:48 2002
@@ -295,6 +295,18 @@
.release = seq_release,
};
+extern struct seq_operations swaps_op;
+static int swaps_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &swaps_op);
+}
+static struct file_operations proc_swaps_operations = {
+ .open = swaps_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
#ifdef CONFIG_MODULES
extern struct seq_operations modules_op;
static int modules_open(struct inode *inode, struct file *file)
@@ -503,13 +515,6 @@
return proc_calc_metrics(page, start, off, count, eof, len);
}
-static int swaps_read_proc(char *page, char **start, off_t off,
- int count, int *eof, void *data)
-{
- int len = get_swaparea_info(page);
- return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
static int memory_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
@@ -616,7 +621,6 @@
{"rtc", ds1286_read_proc},
#endif
{"locks", locks_read_proc},
- {"swaps", swaps_read_proc},
{"iomem", memory_read_proc},
{"execdomains", execdomains_read_proc},
{NULL,}
@@ -632,6 +636,7 @@
entry->proc_fops = &proc_kmsg_operations;
create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations);
create_seq_entry("partitions", 0, &proc_partitions_operations);
+ create_seq_entry("swaps", 0, &proc_swaps_operations);
#if !defined(CONFIG_ARCH_S390)
create_seq_entry("interrupts", 0, &proc_interrupts_operations);
#endif
--- ./mm/swapfile.c.swaps Fri Oct 18 21:01:17 2002
+++ ./mm/swapfile.c Wed Oct 23 22:33:27 2002
@@ -15,6 +15,7 @@
#include <linux/shm.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
+#include <linux/seq_file.h>
#include <asm/pgtable.h>
#include <linux/swapops.h>
@@ -1041,45 +1042,89 @@
return err;
}
-int get_swaparea_info(char *buf)
+#ifdef CONFIG_PROC_FS
+/* iterator */
+static void *swap_start(struct seq_file *swap, loff_t *pos)
{
- char * page = (char *) __get_free_page(GFP_KERNEL);
struct swap_info_struct *ptr = swap_info;
- int i, len;
+ int i;
+ loff_t l = *pos;
+ char * page = (char *) __get_free_page(GFP_KERNEL);
if (!page)
- return -ENOMEM;
+ return ERR_PTR(-ENOMEM);
- len = sprintf(buf, "Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n");
- for (i = 0 ; i < nr_swapfiles ; i++, ptr++) {
- int j, usedswap;
- struct file *file;
- char *path;
+ swap->private = page; /* save for swap_show */
+ for (i = 0; i < nr_swapfiles; i++, ptr++) {
if (!(ptr->flags & SWP_USED) || !ptr->swap_map)
continue;
+ if (!l--)
+ return ptr;
+ }
- file = ptr->swap_file;
- path = d_path(file->f_dentry, file->f_vfsmnt, page, PAGE_SIZE);
- for (j = 0,usedswap = 0; j < ptr->max; ++j)
- switch (ptr->swap_map[j]) {
- case SWAP_MAP_BAD:
- case 0:
- continue;
- default:
- usedswap++;
- }
- len += sprintf(buf + len, "%-39s %s\t%d\t%d\t%d\n",
- path,
- S_ISBLK(file->f_dentry->d_inode->i_mode) ?
- "partition" : "file\t",
- ptr->pages << (PAGE_SHIFT - 10),
- usedswap << (PAGE_SHIFT - 10),
- ptr->prio);
+ return NULL;
+}
+
+static void *swap_next(struct seq_file *swap, void *v, loff_t *pos)
+{
+ struct swap_info_struct *ptr = v;
+ void *endptr = (void *) swap_info + nr_swapfiles * sizeof(struct swap_info_struct);
+
+ for (++ptr; ptr < (struct swap_info_struct *) endptr; ptr++) {
+ if (!(ptr->flags & SWP_USED) || !ptr->swap_map)
+ continue;
+ ++*pos;
+ return ptr;
}
- free_page((unsigned long) page);
- return len;
+
+ return NULL;
}
+
+static void swap_stop(struct seq_file *swap, void *v)
+{
+ free_page((unsigned long) swap->private);
+ swap->private = NULL;
+}
+
+static int swap_show(struct seq_file *swap, void *v)
+{
+ struct swap_info_struct *ptr = v;
+ int j, usedswap;
+ struct file *file;
+ char *path;
+
+ if (v == swap_info)
+ seq_puts(swap, "Filename\t\t\t\tType\t\tSize\tUsed\tPriority\n");
+
+ file = ptr->swap_file;
+ path = d_path(file->f_dentry, file->f_vfsmnt, swap->private, PAGE_SIZE);
+
+ for (j = 0, usedswap = 0; j < ptr->max; ++j)
+ switch (ptr->swap_map[j]) {
+ case SWAP_MAP_BAD:
+ case 0:
+ continue;
+ default:
+ usedswap++;
+ }
+ seq_printf(swap, "%-39s %s\t%d\t%d\t%d\n",
+ path,
+ S_ISBLK(file->f_dentry->d_inode->i_mode) ?
+ "partition" : "file\t",
+ ptr->pages << (PAGE_SHIFT - 10),
+ usedswap << (PAGE_SHIFT - 10),
+ ptr->prio);
+ return 0;
+}
+
+struct seq_operations swaps_op = {
+ .start = swap_start,
+ .next = swap_next,
+ .stop = swap_stop,
+ .show = swap_show
+};
+#endif
/*
* Written 01/25/92 by Simmule Turner, heavily changed by Linus.
-
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:22 EST