s390/zcore: remove memmap device

Remove unused /sys/kernel/debug/zcore/memmap device.
Since at least version 1.24.0 of s390-tools zfcpdump no longer
needs it and reads /proc/vmcore instead.
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

drivers/s390/char/zcore.c

 // SPDX-License-Identifier: GPL-1.0+
 /*
  * zcore module to export memory content and register sets for creating system
- * dumps on SCSI disks (zfcpdump). The "zcore/mem" debugfs file shows the same
- * dump format as s390 standalone dumps.
+ * dumps on SCSI disks (zfcpdump).
  *
  * For more information please refer to Documentation/s390/zfcpdump.rst
  *
@@ -16,7 +15,6 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/debugfs.h>
-#include <linux/memblock.h>
 
 #include <asm/asm-offsets.h>
 #include <asm/ipl.h>
@@ -33,8 +31,6 @@
 
 #define TRACE(x...) debug_sprintf_event(zcore_dbf, 1, x)
 
-#define CHUNK_INFO_SIZE	34 /* 2 16-byte char, each followed by blank */
-
 enum arch_id {
 	ARCH_S390	= 0,
 	ARCH_S390X	= 1,
@@ -48,7 +44,6 @@ struct ipib_info {
 static struct debug_info *zcore_dbf;
 static int hsa_available;
 static struct dentry *zcore_dir;
-static struct dentry *zcore_memmap_file;
 static struct dentry *zcore_reipl_file;
 static struct dentry *zcore_hsa_file;
 static struct ipl_parameter_block *zcore_ipl_block;
@@ -139,46 +134,6 @@ static void release_hsa(void)
 	hsa_available = 0;
 }
 
-static ssize_t zcore_memmap_read(struct file *filp, char __user *buf,
-				 size_t count, loff_t *ppos)
-{
-	return simple_read_from_buffer(buf, count, ppos, filp->private_data,
-				       memblock.memory.cnt * CHUNK_INFO_SIZE);
-}
-
-static int zcore_memmap_open(struct inode *inode, struct file *filp)
-{
-	struct memblock_region *reg;
-	char *buf;
-	int i = 0;
-
-	buf = kcalloc(memblock.memory.cnt, CHUNK_INFO_SIZE, GFP_KERNEL);
-	if (!buf) {
-		return -ENOMEM;
-	}
-	for_each_memblock(memory, reg) {
-		sprintf(buf + (i++ * CHUNK_INFO_SIZE), "%016llx %016llx ",
-			(unsigned long long) reg->base,
-			(unsigned long long) reg->size);
-	}
-	filp->private_data = buf;
-	return nonseekable_open(inode, filp);
-}
-
-static int zcore_memmap_release(struct inode *inode, struct file *filp)
-{
-	kfree(filp->private_data);
-	return 0;
-}
-
-static const struct file_operations zcore_memmap_fops = {
-	.owner		= THIS_MODULE,
-	.read		= zcore_memmap_read,
-	.open		= zcore_memmap_open,
-	.release	= zcore_memmap_release,
-	.llseek		= no_llseek,
-};
-
 static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
 				 size_t count, loff_t *ppos)
 {
@@ -335,17 +290,11 @@ static int __init zcore_init(void)
 		rc = -ENOMEM;
 		goto fail;
 	}
-	zcore_memmap_file = debugfs_create_file("memmap", S_IRUSR, zcore_dir,
-						NULL, &zcore_memmap_fops);
-	if (!zcore_memmap_file) {
-		rc = -ENOMEM;
-		goto fail_dir;
-	}
 	zcore_reipl_file = debugfs_create_file("reipl", S_IRUSR, zcore_dir,
 						NULL, &zcore_reipl_fops);
 	if (!zcore_reipl_file) {
 		rc = -ENOMEM;
-		goto fail_memmap_file;
+		goto fail_dir;
 	}
 	zcore_hsa_file = debugfs_create_file("hsa", S_IRUSR|S_IWUSR, zcore_dir,
 					     NULL, &zcore_hsa_fops);
@@ -357,8 +306,6 @@ static int __init zcore_init(void)
 
 fail_reipl_file:
 	debugfs_remove(zcore_reipl_file);
-fail_memmap_file:
-	debugfs_remove(zcore_memmap_file);
 fail_dir:
 	debugfs_remove(zcore_dir);
 fail: