s390/hypfs: factor out filesystem code

The s390_hypfs filesystem is deprecated and shouldn't be used due to its
rather odd semantics. It creates a whole directory structure with static
file contents so a user can read a consistent state while within that
directory.
Writing to its update attribute will remove and rebuild nearly the whole
filesystem, so that again a user can read a consistent state, even if
multiple files need to be read.

Given that this wastes a lot of CPU cycles, and involves a lot of code,
binary interfaces have been added quite a couple of years ago, which simply
pass the binary data to user space, and let user space decode the data.
This is the preferred and only way how the data should be retrieved.

The assumption is that there are no users of the s390_hypfs filesystem.
However instead of just removing the code, and having to revert in case
there are actually users, factor the filesystem code out and make it only
available via a new config option.

This config option is supposed to be disabled. If it turns out there are no
complaints the filesystem code can be removed probably in a couple of
years.

Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 11 insertions, 164 deletions

diff --git a/arch/s390/hypfs/hypfs_vm.c b/arch/s390/hypfs/hypfs_vm.c
index a3d881ca0a98..3db40ad853e0 100644
--- a/arch/s390/hypfs/hypfs_vm.c
+++ b/arch/s390/hypfs/hypfs_vm.c
@@ -14,47 +14,15 @@
 #include <asm/diag.h>
 #include <asm/ebcdic.h>
 #include <asm/timex.h>
+#include "hypfs_vm.h"
 #include "hypfs.h"
 
-#define NAME_LEN 8
 #define DBFS_D2FC_HDR_VERSION 0
 
 static char local_guest[] = "        ";
 static char all_guests[] = "*       ";
 static char *all_groups = all_guests;
-static char *guest_query;
-
-struct diag2fc_data {
-	__u32 version;
-	__u32 flags;
-	__u64 used_cpu;
-	__u64 el_time;
-	__u64 mem_min_kb;
-	__u64 mem_max_kb;
-	__u64 mem_share_kb;
-	__u64 mem_used_kb;
-	__u32 pcpus;
-	__u32 lcpus;
-	__u32 vcpus;
-	__u32 ocpus;
-	__u32 cpu_max;
-	__u32 cpu_shares;
-	__u32 cpu_use_samp;
-	__u32 cpu_delay_samp;
-	__u32 page_wait_samp;
-	__u32 idle_samp;
-	__u32 other_samp;
-	__u32 total_samp;
-	char  guest_name[NAME_LEN];
-};
-
-struct diag2fc_parm_list {
-	char userid[NAME_LEN];
-	char aci_grp[NAME_LEN];
-	__u64 addr;
-	__u32 size;
-	__u32 fmt;
-};
+char *diag2fc_guest_query;
 
 static int diag2fc(int size, char* query, void *addr)
 {
@@ -62,10 +30,10 @@ static int diag2fc(int size, char* query, void *addr)
 	unsigned long rc;
 	struct diag2fc_parm_list parm_list;
 
-	memcpy(parm_list.userid, query, NAME_LEN);
-	ASCEBC(parm_list.userid, NAME_LEN);
-	memcpy(parm_list.aci_grp, all_groups, NAME_LEN);
-	ASCEBC(parm_list.aci_grp, NAME_LEN);
+	memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN);
+	ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN);
+	memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN);
+	ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN);
 	parm_list.addr = (unsigned long)addr;
 	parm_list.size = size;
 	parm_list.fmt = 0x02;
@@ -87,7 +55,7 @@ static int diag2fc(int size, char* query, void *addr)
 /*
  * Allocate buffer for "query" and store diag 2fc at "offset"
  */
-static void *diag2fc_store(char *query, unsigned int *count, int offset)
+void *diag2fc_store(char *query, unsigned int *count, int offset)
 {
 	void *data;
 	int size;
@@ -108,132 +76,11 @@ static void *diag2fc_store(char *query, unsigned int *count, int offset)
 	return data;
 }
 
-static void diag2fc_free(const void *data)
+void diag2fc_free(const void *data)
 {
 	vfree(data);
 }
 
-#define ATTRIBUTE(dir, name, member) \
-do { \
-	void *rc; \
-	rc = hypfs_create_u64(dir, name, member); \
-	if (IS_ERR(rc)) \
-		return PTR_ERR(rc); \
-} while(0)
-
-static int hypfs_vm_create_guest(struct dentry *systems_dir,
-				 struct diag2fc_data *data)
-{
-	char guest_name[NAME_LEN + 1] = {};
-	struct dentry *guest_dir, *cpus_dir, *samples_dir, *mem_dir;
-	int dedicated_flag, capped_value;
-
-	capped_value = (data->flags & 0x00000006) >> 1;
-	dedicated_flag = (data->flags & 0x00000008) >> 3;
-
-	/* guest dir */
-	memcpy(guest_name, data->guest_name, NAME_LEN);
-	EBCASC(guest_name, NAME_LEN);
-	strim(guest_name);
-	guest_dir = hypfs_mkdir(systems_dir, guest_name);
-	if (IS_ERR(guest_dir))
-		return PTR_ERR(guest_dir);
-	ATTRIBUTE(guest_dir, "onlinetime_us", data->el_time);
-
-	/* logical cpu information */
-	cpus_dir = hypfs_mkdir(guest_dir, "cpus");
-	if (IS_ERR(cpus_dir))
-		return PTR_ERR(cpus_dir);
-	ATTRIBUTE(cpus_dir, "cputime_us", data->used_cpu);
-	ATTRIBUTE(cpus_dir, "capped", capped_value);
-	ATTRIBUTE(cpus_dir, "dedicated", dedicated_flag);
-	ATTRIBUTE(cpus_dir, "count", data->vcpus);
-	/*
-	 * Note: The "weight_min" attribute got the wrong name.
-	 * The value represents the number of non-stopped (operating)
-	 * CPUS.
-	 */
-	ATTRIBUTE(cpus_dir, "weight_min", data->ocpus);
-	ATTRIBUTE(cpus_dir, "weight_max", data->cpu_max);
-	ATTRIBUTE(cpus_dir, "weight_cur", data->cpu_shares);
-
-	/* memory information */
-	mem_dir = hypfs_mkdir(guest_dir, "mem");
-	if (IS_ERR(mem_dir))
-		return PTR_ERR(mem_dir);
-	ATTRIBUTE(mem_dir, "min_KiB", data->mem_min_kb);
-	ATTRIBUTE(mem_dir, "max_KiB", data->mem_max_kb);
-	ATTRIBUTE(mem_dir, "used_KiB", data->mem_used_kb);
-	ATTRIBUTE(mem_dir, "share_KiB", data->mem_share_kb);
-
-	/* samples */
-	samples_dir = hypfs_mkdir(guest_dir, "samples");
-	if (IS_ERR(samples_dir))
-		return PTR_ERR(samples_dir);
-	ATTRIBUTE(samples_dir, "cpu_using", data->cpu_use_samp);
-	ATTRIBUTE(samples_dir, "cpu_delay", data->cpu_delay_samp);
-	ATTRIBUTE(samples_dir, "mem_delay", data->page_wait_samp);
-	ATTRIBUTE(samples_dir, "idle", data->idle_samp);
-	ATTRIBUTE(samples_dir, "other", data->other_samp);
-	ATTRIBUTE(samples_dir, "total", data->total_samp);
-	return 0;
-}
-
-int hypfs_vm_create_files(struct dentry *root)
-{
-	struct dentry *dir, *file;
-	struct diag2fc_data *data;
-	unsigned int count = 0;
-	int rc, i;
-
-	data = diag2fc_store(guest_query, &count, 0);
-	if (IS_ERR(data))
-		return PTR_ERR(data);
-
-	/* Hypervisor Info */
-	dir = hypfs_mkdir(root, "hyp");
-	if (IS_ERR(dir)) {
-		rc = PTR_ERR(dir);
-		goto failed;
-	}
-	file = hypfs_create_str(dir, "type", "z/VM Hypervisor");
-	if (IS_ERR(file)) {
-		rc = PTR_ERR(file);
-		goto failed;
-	}
-
-	/* physical cpus */
-	dir = hypfs_mkdir(root, "cpus");
-	if (IS_ERR(dir)) {
-		rc = PTR_ERR(dir);
-		goto failed;
-	}
-	file = hypfs_create_u64(dir, "count", data->lcpus);
-	if (IS_ERR(file)) {
-		rc = PTR_ERR(file);
-		goto failed;
-	}
-
-	/* guests */
-	dir = hypfs_mkdir(root, "systems");
-	if (IS_ERR(dir)) {
-		rc = PTR_ERR(dir);
-		goto failed;
-	}
-
-	for (i = 0; i < count; i++) {
-		rc = hypfs_vm_create_guest(dir, &(data[i]));
-		if (rc)
-			goto failed;
-	}
-	diag2fc_free(data);
-	return 0;
-
-failed:
-	diag2fc_free(data);
-	return rc;
-}
-
 struct dbfs_d2fc_hdr {
 	u64	len;		/* Length of d2fc buffer without header */
 	u16	version;	/* Version of header */
@@ -252,7 +99,7 @@ static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)
 	struct dbfs_d2fc *d2fc;
 	unsigned int count;
 
-	d2fc = diag2fc_store(guest_query, &count, sizeof(d2fc->hdr));
+	d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr));
 	if (IS_ERR(d2fc))
 		return PTR_ERR(d2fc);
 	store_tod_clock_ext(&d2fc->hdr.tod_ext);
@@ -277,9 +124,9 @@ int hypfs_vm_init(void)
 	if (!MACHINE_IS_VM)
 		return 0;
 	if (diag2fc(0, all_guests, NULL) > 0)
-		guest_query = all_guests;
+		diag2fc_guest_query = all_guests;
 	else if (diag2fc(0, local_guest, NULL) > 0)
-		guest_query = local_guest;
+		diag2fc_guest_query = local_guest;
 	else
 		return -EACCES;
 	hypfs_dbfs_create_file(&dbfs_file_2fc);