1 files changed, 92 insertions, 30 deletions

diff --git a/drivers/s390/cio/blacklist.c b/drivers/s390/cio/blacklist.c
index 25e98483d4e4..daea41c63329 100644
--- a/drivers/s390/cio/blacklist.c
+++ b/drivers/s390/cio/blacklist.c
@@ -15,6 +15,7 @@
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <linux/ctype.h>
 #include <linux/device.h>
 
@@ -279,41 +280,82 @@ blacklist_parse_proc_parameters (char *buf)
         s390_redo_validation ();
 }
 
-/* FIXME: These should be real bus ids and not home-grown ones! */
-static int cio_ignore_read (char *page, char **start, off_t off,
-                            int count, int *eof, void *data)
+/* Iterator struct for all devices. */
+struct ccwdev_iter {
+        int devno;
+        int in_range;
+};
+
+static void *
+cio_ignore_proc_seq_start(struct seq_file *s, loff_t *offset)
 {
-        const unsigned int entry_size = 18; /* "0.0.ABCD-0.0.EFGH\n" */
-        long devno;
-        int len;
-
-        len = 0;
-        for (devno = off; /* abuse the page variable
-                           * as counter, see fs/proc/generic.c */
-             devno < __MAX_SUBCHANNEL && len + entry_size < count; devno++) {
-                if (!test_bit(devno, bl_dev))
-                        continue;
-                len += sprintf(page + len, "0.0.%04lx", devno);
-                if (test_bit(devno + 1, bl_dev)) { /* print range */
-                        while (++devno < __MAX_SUBCHANNEL)
-                                if (!test_bit(devno, bl_dev))
-                                        break;
-                        len += sprintf(page + len, "-0.0.%04lx", --devno);
-                }
-                len += sprintf(page + len, "\n");
-        }
+        struct ccwdev_iter *iter;
+
+        if (*offset > __MAX_SUBCHANNEL)
+                return NULL;
+        iter = kmalloc(sizeof(struct ccwdev_iter), GFP_KERNEL);
+        if (!iter)
+                return ERR_PTR(-ENOMEM);
+        memset(iter, 0, sizeof(struct ccwdev_iter));
+        iter->devno = *offset;
+        return iter;
+}
+
+static void
+cio_ignore_proc_seq_stop(struct seq_file *s, void *it)
+{
+        if (!IS_ERR(it))
+                kfree(it);
+}
 
-        if (devno < __MAX_SUBCHANNEL)
-                *eof = 1;
-        *start = (char *) (devno - off); /* number of checked entries */
-        return len;
+static void *
+cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
+{
+        struct ccwdev_iter *iter;
+
+        if (*offset > __MAX_SUBCHANNEL)
+                return NULL;
+        iter = (struct ccwdev_iter *)it;
+        iter->devno++;
+        (*offset)++;
+        return iter;
 }
 
-static int cio_ignore_write(struct file *file, const char __user *user_buf,
-                             unsigned long user_len, void *data)
+static int
+cio_ignore_proc_seq_show(struct seq_file *s, void *it)
+{
+        struct ccwdev_iter *iter;
+
+        iter = (struct ccwdev_iter *)it;
+        if (!is_blacklisted(iter->devno))
+                /* Not blacklisted, nothing to output. */
+                return 0;
+        if (!iter->in_range) {
+                /* First device in range. */
+                if ((iter->devno == __MAX_SUBCHANNEL) ||
+                    !is_blacklisted(iter->devno + 1))
+                        /* Singular device. */
+                        return seq_printf(s, "0.0.%04x\n", iter->devno);
+                iter->in_range = 1;
+                return seq_printf(s, "0.0.%04x-", iter->devno);
+        }
+        if ((iter->devno == __MAX_SUBCHANNEL) ||
+            !is_blacklisted(iter->devno + 1)) {
+                /* Last device in range. */
+                iter->in_range = 0;
+                return seq_printf(s, "0.0.%04x\n", iter->devno);
+        }
+        return 0;
+}
+
+static ssize_t
+cio_ignore_write(struct file *file, const char __user *user_buf,
+                 size_t user_len, loff_t *offset)
 {
         char *buf;
 
+        if (*offset)
+                return -EINVAL;
         if (user_len > 65536)
                 user_len = 65536;
         buf = vmalloc (user_len + 1); /* maybe better use the stack? */
@@ -331,6 +373,27 @@ static int cio_ignore_write(struct file *file, const char __user *user_buf,
         return user_len;
 }
 
+static struct seq_operations cio_ignore_proc_seq_ops = {
+        .start = cio_ignore_proc_seq_start,
+        .stop  = cio_ignore_proc_seq_stop,
+        .next  = cio_ignore_proc_seq_next,
+        .show  = cio_ignore_proc_seq_show,
+};
+
+static int
+cio_ignore_proc_open(struct inode *inode, struct file *file)
+{
+        return seq_open(file, &cio_ignore_proc_seq_ops);
+}
+
+static struct file_operations cio_ignore_proc_fops = {
+        .open    = cio_ignore_proc_open,
+        .read    = seq_read,
+        .llseek  = seq_lseek,
+        .release = seq_release,
+        .write   = cio_ignore_write,
+};
+
 static int
 cio_ignore_proc_init (void)
 {
@@ -341,8 +404,7 @@ cio_ignore_proc_init (void)
         if (!entry)
                 return 0;
 
-        entry->read_proc  = cio_ignore_read;
-        entry->write_proc = cio_ignore_write;
+        entry->proc_fops = &cio_ignore_proc_fops;
 
         return 1;
 }