pstore improvements:

- refactor init to happen as early as possible again (Joel Fernandes)
 - improve resource reservation names
 -----BEGIN PGP SIGNATURE-----
 Comment: Kees Cook <kees@outflux.net>
 
 iQJKBAABCgA0FiEEpcP2jyKd1g9yPm4TiXL039xtwCYFAlvN3UwWHGtlZXNjb29r
 QGNocm9taXVtLm9yZwAKCRCJcvTf3G3AJkiZD/0Xx72AvLGBOBMmnTm1cP+p8A6k
 wLG4ThW5Hg7ArQ5RSsADFr2jidIFFyq6I7k0U5oj4E/hS9chbNQjvbzXCaNbkl5O
 TYy7usATrjLcR6ivGFKM1eTuN9rFb7zaWKkh08ORf5+aP/yS0yezdLSbGqHiJyas
 MJ/HvFRPeN6tqd6qyDme7WkOrdGyGWSs3VV44izvBqo4Ub7JFRmjegJOhyEh0TRf
 jobpkuEw0EzTiVqDyIBtqJdhZRiWzScS5gwNi0L6QOlsnnRoAVEYGKhBMEhLCtBx
 nUDZdaC0FhsjRXdqbt08ylQ8bRU6xKWLvKrQ4xdbDwFC4oI8H+ZVg0YUfhp3juH8
 wlvo1MoHJJryDQCTrqvW4KY8Hkz3uF5vE8KoEo6wX2+o9mRw+H/ArCL1pMQ15eIH
 3yPESbkSW/SOOehFcFp2IosqE2XrflzJLQ1IRgoe/E7rO99Kpp9INZZMT0jNtoHx
 2E/u6DpCPrQk+5ko+we/jfu4P2SoctpLSnN87O5mI9SD7fjpBOle1y0vo/gUEYsL
 0mB165FdP7Qjqc+vqDT3VxyY/44ZEZI0kJYyE7k0nLkEijSagLyI750qpyB4DN95
 Y10sPrDFICyhC7N+uOTGG/Ey4mIdpp6tiWsPbF9TLewdsM3EfvkzmYPSWUYaEDp3
 MCZ2680KUHdMHPidBA==
 =fe5o
 -----END PGP SIGNATURE-----

Merge tag 'pstore-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "pstore improvements:

   - refactor init to happen as early as possible again (Joel Fernandes)

   - improve resource reservation names"

* tag 'pstore-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Clarify resource reservation labels
  pstore: Refactor compression initialization
  pstore: Allocate compression during late_initcall()
  pstore: Centralize init/exit routines

fs/pstore/inode.c

@@ -482,12 +482,10 @@ static struct file_system_type pstore_fs_type = {
 	.kill_sb	= pstore_kill_sb,
 };
 
-static int __init init_pstore_fs(void)
+int __init pstore_init_fs(void)
 {
 	int err;
 
-	pstore_choose_compression();
-
 	/* Create a convenient mount point for people to access pstore */
 	err = sysfs_create_mount_point(fs_kobj, "pstore");
 	if (err)
@@ -500,14 +498,9 @@ static int __init init_pstore_fs(void)
 out:
 	return err;
 }
-module_init(init_pstore_fs)
 
-static void __exit exit_pstore_fs(void)
+void __exit pstore_exit_fs(void)
 {
 	unregister_filesystem(&pstore_fs_type);
 	sysfs_remove_mount_point(fs_kobj, "pstore");
 }
-module_exit(exit_pstore_fs)
-
-MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
-MODULE_LICENSE("GPL");

fs/pstore/internal.h

@@ -37,7 +37,8 @@ extern bool	pstore_is_mounted(void);
 extern void	pstore_record_init(struct pstore_record *record,
 				   struct pstore_info *psi);
 
-/* Called during module_init() */
+/* Called during pstore init/exit. */
-extern void __init pstore_choose_compression(void);
+int __init	pstore_init_fs(void);
+void __exit	pstore_exit_fs(void);
 
 #endif

fs/pstore/platform.c

@@ -274,36 +274,56 @@ static int pstore_decompress(void *in, void *out,
 
 static void allocate_buf_for_compression(void)
 {
+	struct crypto_comp *ctx;
+	int size;
+	char *buf;
+
+	/* Skip if not built-in or compression backend not selected yet. */
 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !zbackend)
 		return;
 
+	/* Skip if no pstore backend yet or compression init already done. */
+	if (!psinfo || tfm)
+		return;
+
 	if (!crypto_has_comp(zbackend->name, 0, 0)) {
-		pr_err("No %s compression\n", zbackend->name);
+		pr_err("Unknown compression: %s\n", zbackend->name);
 		return;
 	}
 
-	big_oops_buf_sz = zbackend->zbufsize(psinfo->bufsize);
+	size = zbackend->zbufsize(psinfo->bufsize);
-	if (big_oops_buf_sz <= 0)
+	if (size <= 0) {
-		return;
+		pr_err("Invalid compression size for %s: %d\n",
-
+		       zbackend->name, size);
-	big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
-	if (!big_oops_buf) {
-		pr_err("allocate compression buffer error!\n");
 		return;
 	}
 
-	tfm = crypto_alloc_comp(zbackend->name, 0, 0);
+	buf = kmalloc(size, GFP_KERNEL);
-	if (IS_ERR_OR_NULL(tfm)) {
+	if (!buf) {
-		kfree(big_oops_buf);
+		pr_err("Failed %d byte compression buffer allocation for: %s\n",
-		big_oops_buf = NULL;
+		       size, zbackend->name);
-		pr_err("crypto_alloc_comp() failed!\n");
 		return;
 	}
+
+	ctx = crypto_alloc_comp(zbackend->name, 0, 0);
+	if (IS_ERR_OR_NULL(ctx)) {
+		kfree(buf);
+		pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
+		       PTR_ERR(ctx));
+		return;
+	}
+
+	/* A non-NULL big_oops_buf indicates compression is available. */
+	tfm = ctx;
+	big_oops_buf_sz = size;
+	big_oops_buf = buf;
+
+	pr_info("Using compression: %s\n", zbackend->name);
 }
 
 static void free_buf_for_compression(void)
 {
-	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && !IS_ERR_OR_NULL(tfm))
+	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm)
 		crypto_free_comp(tfm);
 	kfree(big_oops_buf);
 	big_oops_buf = NULL;
@@ -774,14 +794,43 @@ void __init pstore_choose_compression(void)
 	for (step = zbackends; step->name; step++) {
 		if (!strcmp(compress, step->name)) {
 			zbackend = step;
-			pr_info("using %s compression\n", zbackend->name);
 			return;
 		}
 	}
 }
 
+static int __init pstore_init(void)
+{
+	int ret;
+
+	pstore_choose_compression();
+
+	/*
+	 * Check if any pstore backends registered earlier but did not
+	 * initialize compression because crypto was not ready. If so,
+	 * initialize compression now.
+	 */
+	allocate_buf_for_compression();
+
+	ret = pstore_init_fs();
+	if (ret)
+		return ret;
+
+	return 0;
+}
+late_initcall(pstore_init);
+
+static void __exit pstore_exit(void)
+{
+	pstore_exit_fs();
+}
+module_exit(pstore_exit)
+
 module_param(compress, charp, 0444);
 MODULE_PARM_DESC(compress, "Pstore compression to use");
 
 module_param(backend, charp, 0444);
 MODULE_PARM_DESC(backend, "Pstore backend to use");
+
+MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
+MODULE_LICENSE("GPL");

fs/pstore/ram.c

@@ -587,9 +587,16 @@ static int ramoops_init_przs(const char *name,
 		goto fail;
 
 	for (i = 0; i < *cnt; i++) {
+		char *label;
+
+		if (*cnt == 1)
+			label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
+		else
+			label = kasprintf(GFP_KERNEL, "ramoops:%s(%d/%d)",
+					  name, i, *cnt - 1);
 		prz_ar[i] = persistent_ram_new(*paddr, zone_sz, sig,
-						  &cxt->ecc_info,
+					       &cxt->ecc_info,
-						  cxt->memtype, flags);
+					       cxt->memtype, flags, label);
 		if (IS_ERR(prz_ar[i])) {
 			err = PTR_ERR(prz_ar[i]);
 			dev_err(dev, "failed to request %s mem region (0x%zx@0x%llx): %d\n",
@@ -619,6 +626,8 @@ static int ramoops_init_prz(const char *name,
 			    struct persistent_ram_zone **prz,
 			    phys_addr_t *paddr, size_t sz, u32 sig)
 {
+	char *label;
+
 	if (!sz)
 		return 0;
 
@@ -629,8 +638,9 @@ static int ramoops_init_prz(const char *name,
 		return -ENOMEM;
 	}
 
+	label = kasprintf(GFP_KERNEL, "ramoops:%s", name);
 	*prz = persistent_ram_new(*paddr, sz, sig, &cxt->ecc_info,
-				  cxt->memtype, 0);
+				  cxt->memtype, 0, label);
 	if (IS_ERR(*prz)) {
 		int err = PTR_ERR(*prz);
 
@@ -962,7 +972,7 @@ static int __init ramoops_init(void)
 
 	return ret;
 }
-late_initcall(ramoops_init);
+postcore_initcall(ramoops_init);
 
 static void __exit ramoops_exit(void)
 {

fs/pstore/ram_core.c

@@ -438,11 +438,11 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size,
 }
 
 static void *persistent_ram_iomap(phys_addr_t start, size_t size,
-		unsigned int memtype)
+		unsigned int memtype, char *label)
 {
 	void *va;
 
-	if (!request_mem_region(start, size, "persistent_ram")) {
+	if (!request_mem_region(start, size, label ?: "ramoops")) {
 		pr_err("request mem region (0x%llx@0x%llx) failed\n",
 			(unsigned long long)size, (unsigned long long)start);
 		return NULL;
@@ -470,7 +470,8 @@ static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
 	if (pfn_valid(start >> PAGE_SHIFT))
 		prz->vaddr = persistent_ram_vmap(start, size, memtype);
 	else
-		prz->vaddr = persistent_ram_iomap(start, size, memtype);
+		prz->vaddr = persistent_ram_iomap(start, size, memtype,
+						  prz->label);
 
 	if (!prz->vaddr) {
 		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
@@ -541,12 +542,13 @@ void persistent_ram_free(struct persistent_ram_zone *prz)
 	prz->ecc_info.par = NULL;
 
 	persistent_ram_free_old(prz);
+	kfree(prz->label);
 	kfree(prz);
 }
 
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
-			unsigned int memtype, u32 flags)
+			unsigned int memtype, u32 flags, char *label)
 {
 	struct persistent_ram_zone *prz;
 	int ret = -ENOMEM;
@@ -560,6 +562,7 @@ struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 	/* Initialize general buffer state. */
 	raw_spin_lock_init(&prz->buffer_lock);
 	prz->flags = flags;
+	prz->label = label;
 
 	ret = persistent_ram_buffer_map(start, size, prz, memtype);
 	if (ret)

include/linux/pstore_ram.h

@@ -46,6 +46,7 @@ struct persistent_ram_zone {
 	phys_addr_t paddr;
 	size_t size;
 	void *vaddr;
+	char *label;
 	struct persistent_ram_buffer *buffer;
 	size_t buffer_size;
 	u32 flags;
@@ -65,7 +66,7 @@ struct persistent_ram_zone {
 
 struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
 			u32 sig, struct persistent_ram_ecc_info *ecc_info,
-			unsigned int memtype, u32 flags);
+			unsigned int memtype, u32 flags, char *label);
 void persistent_ram_free(struct persistent_ram_zone *prz);
 void persistent_ram_zap(struct persistent_ram_zone *prz);