nfs: disintegrate UAPI for nfs

This is to complete part of the Userspace API (UAPI) disintegration for which
the preparatory patches were pulled recently.  After these patches, userspace
headers will be segregated into:

        include/uapi/linux/.../foo.h

for the userspace interface stuff, and:

        include/linux/.../foo.h

for the strictly kernel internal stuff.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

5 files changed, 125 insertions, 15 deletions

diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index d39bb5cce883..ca71db69da07 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -23,6 +23,7 @@ config PSTORE_FTRACE
 	bool "Persistent function tracer"
 	depends on PSTORE
 	depends on FUNCTION_TRACER
+	depends on DEBUG_FS
 	help
 	  With this option kernel traces function calls into a persistent
 	  ram buffer that can be decoded and dumped after reboot through
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index a130d484b7d3..2d57e1ac0115 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -17,19 +17,113 @@
 #include <linux/percpu.h>
 #include <linux/smp.h>
 #include <linux/atomic.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/ftrace.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/cache.h>
 #include <asm/barrier.h>
 #include "internal.h"
 
-void notrace pstore_ftrace_call(unsigned long ip, unsigned long parent_ip)
+static void notrace pstore_ftrace_call(unsigned long ip,
+				       unsigned long parent_ip)
 {
+	unsigned long flags;
 	struct pstore_ftrace_record rec = {};
 
 	if (unlikely(oops_in_progress))
 		return;
 
+	local_irq_save(flags);
+
 	rec.ip = ip;
 	rec.parent_ip = parent_ip;
 	pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
 	psinfo->write_buf(PSTORE_TYPE_FTRACE, 0, NULL, 0, (void *)&rec,
 			  sizeof(rec), psinfo);
+
+	local_irq_restore(flags);
+}
+
+static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
+	.func	= pstore_ftrace_call,
+};
+
+static DEFINE_MUTEX(pstore_ftrace_lock);
+static bool pstore_ftrace_enabled;
+
+static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
+					size_t count, loff_t *ppos)
+{
+	u8 on;
+	ssize_t ret;
+
+	ret = kstrtou8_from_user(buf, count, 2, &on);
+	if (ret)
+		return ret;
+
+	mutex_lock(&pstore_ftrace_lock);
+
+	if (!on ^ pstore_ftrace_enabled)
+		goto out;
+
+	if (on)
+		ret = register_ftrace_function(&pstore_ftrace_ops);
+	else
+		ret = unregister_ftrace_function(&pstore_ftrace_ops);
+	if (ret) {
+		pr_err("%s: unable to %sregister ftrace ops: %zd\n",
+		       __func__, on ? "" : "un", ret);
+		goto err;
+	}
+
+	pstore_ftrace_enabled = on;
+out:
+	ret = count;
+err:
+	mutex_unlock(&pstore_ftrace_lock);
+
+	return ret;
+}
+
+static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
+				       size_t count, loff_t *ppos)
+{
+	char val[] = { '0' + pstore_ftrace_enabled, '\n' };
+
+	return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
+}
+
+static const struct file_operations pstore_knob_fops = {
+	.open	= simple_open,
+	.read	= pstore_ftrace_knob_read,
+	.write	= pstore_ftrace_knob_write,
+};
+
+void pstore_register_ftrace(void)
+{
+	struct dentry *dir;
+	struct dentry *file;
+
+	if (!psinfo->write_buf)
+		return;
+
+	dir = debugfs_create_dir("pstore", NULL);
+	if (!dir) {
+		pr_err("%s: unable to create pstore directory\n", __func__);
+		return;
+	}
+
+	file = debugfs_create_file("record_ftrace", 0600, dir, NULL,
+				   &pstore_knob_fops);
+	if (!file) {
+		pr_err("%s: unable to create record_ftrace file\n", __func__);
+		goto err_file;
+	}
+
+	return;
+err_file:
+	debugfs_remove(dir);
 }
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 0d0d3b7d5f12..4847f588b7d5 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -39,6 +39,12 @@ pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
 #endif
 }
 
+#ifdef CONFIG_PSTORE_FTRACE
+extern void pstore_register_ftrace(void);
+#else
+static inline void pstore_register_ftrace(void) {}
+#endif
+
 extern struct pstore_info *psinfo;
 
 extern void	pstore_set_kmsg_bytes(int);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 29996e8793a7..a40da07e93d6 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -164,7 +164,13 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
 
 		if (c > psinfo->bufsize)
 			c = psinfo->bufsize;
-		spin_lock_irqsave(&psinfo->buf_lock, flags);
+
+		if (oops_in_progress) {
+			if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
+				break;
+		} else {
+			spin_lock_irqsave(&psinfo->buf_lock, flags);
+		}
 		memcpy(psinfo->buf, s, c);
 		psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
 		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
@@ -236,6 +242,7 @@ int pstore_register(struct pstore_info *psi)
 
 	kmsg_dump_register(&pstore_dumper);
 	pstore_register_console();
+	pstore_register_ftrace();
 
 	if (pstore_update_ms >= 0) {
 		pstore_timer.expires = jiffies +
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 0b311bc18916..1a4f6da58eab 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -32,6 +32,7 @@
 #include <linux/ioport.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/compiler.h>
 #include <linux/pstore_ram.h>
 
 #define RAMOOPS_KERNMSG_HDR "===="
@@ -181,12 +182,11 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
 	return len;
 }
 
-
-static int ramoops_pstore_write_buf(enum pstore_type_id type,
-				    enum kmsg_dump_reason reason,
-				    u64 *id, unsigned int part,
-				    const char *buf, size_t size,
-				    struct pstore_info *psi)
+static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
+					    enum kmsg_dump_reason reason,
+					    u64 *id, unsigned int part,
+					    const char *buf, size_t size,
+					    struct pstore_info *psi)
 {
 	struct ramoops_context *cxt = psi->data;
 	struct persistent_ram_zone *prz = cxt->przs[cxt->dump_write_cnt];
@@ -406,7 +406,7 @@ static int __devinit ramoops_probe(struct platform_device *pdev)
 		goto fail_init_fprz;
 
 	if (!cxt->przs && !cxt->cprz && !cxt->fprz) {
-		pr_err("memory size too small, minimum is %lu\n",
+		pr_err("memory size too small, minimum is %zu\n",
 			cxt->console_size + cxt->record_size +
 			cxt->ftrace_size);
 		goto fail_cnt;
@@ -414,13 +414,14 @@ static int __devinit ramoops_probe(struct platform_device *pdev)
 
 	cxt->pstore.data = cxt;
 	/*
-	 * Console can handle any buffer size, so prefer dumps buffer
-	 * size since usually it is smaller.
+	 * Console can handle any buffer size, so prefer LOG_LINE_MAX. If we
+	 * have to handle dumps, we must have at least record_size buffer. And
+	 * for ftrace, bufsize is irrelevant (if bufsize is 0, buf will be
+	 * ZERO_SIZE_PTR).
 	 */
-	if (cxt->przs)
-		cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
-	else
-		cxt->pstore.bufsize = cxt->cprz->buffer_size;
+	if (cxt->console_size)
+		cxt->pstore.bufsize = 1024; /* LOG_LINE_MAX */
+	cxt->pstore.bufsize = max(cxt->record_size, cxt->pstore.bufsize);
 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
 	spin_lock_init(&cxt->pstore.buf_lock);
 	if (!cxt->pstore.buf) {
@@ -537,6 +538,7 @@ postcore_initcall(ramoops_init);
 static void __exit ramoops_exit(void)
 {
 	platform_driver_unregister(&ramoops_driver);
+	platform_device_unregister(dummy);
 	kfree(dummy_data);
 }
 module_exit(ramoops_exit);