kerndat: Collect all global variables on one struct

Not to spoil the global namespace and unify the kerndat
data names.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-check.c

@@ -566,7 +566,7 @@ static int check_mem_dirty_track(void)
 	if (kerndat_get_dirty_track() < 0)
 		return -1;
 
-	if (!kerndat_has_dirty_track)
+	if (!kdat.has_dirty_track)
 		pr_warn("Dirty tracking is OFF. Memory snapshot will not work.\n");
 	return 0;
 }

cr-restore.c

@@ -2249,7 +2249,7 @@ static int prepare_creds(int pid, struct task_restore_args *args)
 
 	creds_entry__free_unpacked(ce, NULL);
 
-	args->cap_last_cap = kern_last_cap;
+	args->cap_last_cap = kdat.last_cap;
 
 	/* XXX -- validate creds here? */
 

include/kerndat.h

@@ -14,14 +14,17 @@ extern int kerndat_init(void);
 extern int kerndat_init_rst(void);
 extern int kerndat_get_dirty_track(void);
 
-extern dev_t kerndat_shmem_dev;
-extern bool kerndat_has_dirty_track;
+struct kerndat_s {
+	dev_t shmem_dev;
+	int tcp_max_wshare;
+	int tcp_max_rshare;
+	int last_cap;
+	u64 zero_page_pfn;
+	bool has_dirty_track;
+	bool has_memfd;
+};
 
-extern int tcp_max_wshare;
-extern int tcp_max_rshare;
-
-extern int kern_last_cap;
-extern u64 zero_page_pfn;
+extern struct kerndat_s kdat;
 
 enum {
 	KERNDAT_FS_STAT_DEVPTS,
@@ -32,6 +35,4 @@ enum {
 
 extern struct stat *kerndat_get_fs_stat(unsigned int which);
 
-extern bool memfd_is_supported;
-
 #endif /* __CR_KERNDAT_H__ */

kerndat.c

@@ -18,7 +18,10 @@
 #include "cr_options.h"
 #include "util.h"
 
-dev_t kerndat_shmem_dev;
+struct kerndat_s kdat = {
+	.tcp_max_wshare = 2U << 20,
+	.tcp_max_rshare = 3U << 20,
+};
 
 /*
  * Anonymous shared mappings are backed by hidden tmpfs
@@ -49,8 +52,8 @@ static int kerndat_get_shmemdev(void)
 
 	munmap(map, PAGE_SIZE);
 
-	kerndat_shmem_dev = buf.st_dev;
-	pr_info("Found anon-shmem device at %"PRIx64"\n", kerndat_shmem_dev);
+	kdat.shmem_dev = buf.st_dev;
+	pr_info("Found anon-shmem device at %"PRIx64"\n", kdat.shmem_dev);
 	return 0;
 }
 
@@ -105,8 +108,6 @@ struct stat *kerndat_get_fs_stat(unsigned int which)
  * this functionality under CONFIG_MEM_SOFT_DIRTY option.
  */
 
-bool kerndat_has_dirty_track = false;
-
 int kerndat_get_dirty_track(void)
 {
 	char *map;
@@ -146,7 +147,7 @@ int kerndat_get_dirty_track(void)
 
 	if (pmap & PME_SOFT_DIRTY) {
 		pr_info("Dirty track supported on kernel\n");
-		kerndat_has_dirty_track = true;
+		kdat.has_dirty_track = true;
 	} else {
 		pr_info("Dirty tracking support is OFF\n");
 		if (opts.track_mem) {
@@ -167,8 +168,6 @@ int kerndat_get_dirty_track(void)
  * Meanwhile set it up to 2M and 3M, which is safe enough to
  * proceed without errors.
  */
-int tcp_max_wshare = 2U << 20;
-int tcp_max_rshare = 3U << 20;
 
 static int tcp_read_sysctl_limits(void)
 {
@@ -191,19 +190,17 @@ static int tcp_read_sysctl_limits(void)
 		goto out;
 	}
 
-	tcp_max_wshare = min(tcp_max_wshare, (int)vect[0][2]);
-	tcp_max_rshare = min(tcp_max_rshare, (int)vect[1][2]);
+	kdat.tcp_max_wshare = min(kdat.tcp_max_wshare, (int)vect[0][2]);
+	kdat.tcp_max_rshare = min(kdat.tcp_max_rshare, (int)vect[1][2]);
 
-	if (tcp_max_wshare < 128 || tcp_max_rshare < 128)
+	if (kdat.tcp_max_wshare < 128 || kdat.tcp_max_rshare < 128)
 		pr_warn("The memory limits for TCP queues are suspiciously small\n");
 out:
-	pr_debug("TCP queue memory limits are %d:%d\n", tcp_max_wshare, tcp_max_rshare);
+	pr_debug("TCP queue memory limits are %d:%d\n", kdat.tcp_max_wshare, kdat.tcp_max_rshare);
 	return 0;
 }
 
 /* The page frame number (PFN) is constant for the zero page */
-u64 zero_page_pfn;
-
 static int init_zero_page_pfn()
 {
 	void *addr;
@@ -220,28 +217,25 @@ static int init_zero_page_pfn()
 		return -1;
 	}
 
-	ret = vaddr_to_pfn((unsigned long)addr, &zero_page_pfn);
+	ret = vaddr_to_pfn((unsigned long)addr, &kdat.zero_page_pfn);
 	munmap(addr, PAGE_SIZE);
 
-	if (zero_page_pfn == 0)
+	if (kdat.zero_page_pfn == 0)
 		ret = -1;
 
 	return ret;
 }
 
-int kern_last_cap;
-
 int get_last_cap(void)
 {
 	struct sysctl_req req[] = {
-		{ "kernel/cap_last_cap", &kern_last_cap, CTL_U32 },
+		{ "kernel/cap_last_cap", &kdat.last_cap, CTL_U32 },
 		{ },
 	};
 
 	return sysctl_op(req, CTL_READ);
 }
 
-bool memfd_is_supported;
 static bool kerndat_has_memfd_create(void)
 {
 	int ret;
@@ -249,9 +243,9 @@ static bool kerndat_has_memfd_create(void)
 	ret = sys_memfd_create(NULL, 0);
 
 	if (ret == -ENOSYS)
-		memfd_is_supported = false;
+		kdat.has_memfd = false;
 	else if (ret == -EFAULT)
-		memfd_is_supported = true;
+		kdat.has_memfd = true;
 	else {
 		pr_err("Unexpected error %d from memfd_create(NULL, 0)\n", ret);
 		return -1;

mem.c

@@ -29,7 +29,7 @@ static int task_reset_dirty_track(int pid)
 	if (!opts.track_mem)
 		return 0;
 
-	BUG_ON(!kerndat_has_dirty_track);
+	BUG_ON(!kdat.has_dirty_track);
 
 	return do_task_reset_dirty_track(pid);
 }
@@ -92,7 +92,7 @@ static inline bool should_dump_page(VmaEntry *vmae, u64 pme)
 		return false;
 	if (pme & PME_SWAP)
 		return true;
-	if ((pme & PME_PRESENT) && ((pme & PME_PFRAME_MASK) != zero_page_pfn))
+	if ((pme & PME_PRESENT) && ((pme & PME_PFRAME_MASK) != kdat.zero_page_pfn))
 		return true;
 
 	return false;
@@ -251,7 +251,7 @@ static int __parasite_dump_pages_seized(struct parasite_ctl *ctl,
 	pr_info("Dumping pages (type: %d pid: %d)\n", CR_FD_PAGES, ctl->pid.real);
 	pr_info("----------------------------------------\n");
 
-	BUG_ON(zero_page_pfn == 0);
+	BUG_ON(kdat.zero_page_pfn == 0);
 
 	timing_start(TIME_MEMDUMP);
 

parasite-syscall.c

@@ -737,7 +737,7 @@ int parasite_dump_creds(struct parasite_ctl *ctl, CredsEntry *ce)
 	BUILD_BUG_ON(sizeof(*pc) > PAGE_SIZE);
 
 	pc = parasite_args(ctl, struct parasite_dump_creds);
-	pc->cap_last_cap = kern_last_cap;
+	pc->cap_last_cap = kdat.last_cap;
 
 	if (parasite_execute_daemon(PARASITE_CMD_DUMP_CREDS, ctl) < 0)
 		return -1;

proc_parse.c

@@ -174,7 +174,7 @@ static int parse_vmflags(char *buf, struct vma_area *vma_area)
 
 static inline int is_anon_shmem_map(dev_t dev)
 {
-	return kerndat_shmem_dev == dev;
+	return kdat.shmem_dev == dev;
 }
 
 struct vma_file_info {

shmem.c

@@ -191,7 +191,7 @@ int get_shmem_fd(int pid, VmaEntry *vi)
 		return dup(si->fd);
 
 	flags = MAP_SHARED;
-	if (memfd_is_supported) {
+	if (kdat.has_memfd) {
 		f = sys_memfd_create("", 0);
 		if (f < 0) {
 			pr_perror("Unable to create memfd");

sk-tcp.c

@@ -466,7 +466,7 @@ static int __send_tcp_queue(int sk, int queue, u32 len, struct cr_img *img)
 	if (read_img_buf(img, buf, len) < 0)
 		goto err;
 
-	max = (queue == TCP_SEND_QUEUE) ? tcp_max_wshare : tcp_max_rshare;
+	max = (queue == TCP_SEND_QUEUE) ? kdat.tcp_max_wshare : kdat.tcp_max_rshare;
 	off = 0;
 	while (len) {
 		int chunk = (len > max ? max : len);