Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML updates from Richard Weinberger:
 "This pile contains mostly fixes and improvements for issues identified
  by Richard W M Jones while adding UML as backend to libguestfs"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Add irq chip um/mask handlers
  um: prctl: Do not include linux/ptrace.h
  um: Run UML in it's own session.
  um: Cleanup SIGTERM handling
  um: ubd: Introduce submit_request()
  um: ubd: Add REQ_FLUSH suppport
  um: Implement probe_kernel_read()
  um: hostfs: Fix writeback

arch/um/drivers/ubd.h

@@ -7,7 +7,6 @@
 #ifndef __UM_UBD_USER_H
 #define __UM_UBD_USER_H
 
-extern void ignore_sigwinch_sig(void);
 extern int start_io_thread(unsigned long sp, int *fds_out);
 extern int io_thread(void *arg);
 extern int kernel_fd;

arch/um/drivers/ubd_kern.c

@@ -41,7 +41,7 @@
 #include <os.h>
 #include "cow.h"
 
-enum ubd_req { UBD_READ, UBD_WRITE };
+enum ubd_req { UBD_READ, UBD_WRITE, UBD_FLUSH };
 
 struct io_thread_req {
 	struct request *req;
@@ -866,6 +866,7 @@ static int ubd_add(int n, char **error_out)
 		goto out;
 	}
 	ubd_dev->queue->queuedata = ubd_dev;
+	blk_queue_flush(ubd_dev->queue, REQ_FLUSH);
 
 	blk_queue_max_segments(ubd_dev->queue, MAX_SG);
 	err = ubd_disk_register(UBD_MAJOR, ubd_dev->size, n, &ubd_gendisk[n]);
@@ -1238,12 +1239,41 @@ static void prepare_request(struct request *req, struct io_thread_req *io_req,
 
 }
 
+/* Called with dev->lock held */
+static void prepare_flush_request(struct request *req,
+				  struct io_thread_req *io_req)
+{
+	struct gendisk *disk = req->rq_disk;
+	struct ubd *ubd_dev = disk->private_data;
+
+	io_req->req = req;
+	io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd :
+		ubd_dev->fd;
+	io_req->op = UBD_FLUSH;
+}
+
+static bool submit_request(struct io_thread_req *io_req, struct ubd *dev)
+{
+	int n = os_write_file(thread_fd, &io_req,
+			     sizeof(io_req));
+	if (n != sizeof(io_req)) {
+		if (n != -EAGAIN)
+			printk("write to io thread failed, "
+			       "errno = %d\n", -n);
+		else if (list_empty(&dev->restart))
+			list_add(&dev->restart, &restart);
+
+		kfree(io_req);
+		return false;
+	}
+	return true;
+}
+
 /* Called with dev->lock held */
 static void do_ubd_request(struct request_queue *q)
 {
 	struct io_thread_req *io_req;
 	struct request *req;
-	int n;
 
 	while(1){
 		struct ubd *dev = q->queuedata;
@@ -1259,6 +1289,19 @@ static void do_ubd_request(struct request_queue *q)
 		}
 
 		req = dev->request;
+
+		if (req->cmd_flags & REQ_FLUSH) {
+			io_req = kmalloc(sizeof(struct io_thread_req),
+					 GFP_ATOMIC);
+			if (io_req == NULL) {
+				if (list_empty(&dev->restart))
+					list_add(&dev->restart, &restart);
+				return;
+			}
+			prepare_flush_request(req, io_req);
+			submit_request(io_req, dev);
+		}
+
 		while(dev->start_sg < dev->end_sg){
 			struct scatterlist *sg = &dev->sg[dev->start_sg];
 
@@ -1273,17 +1316,8 @@ static void do_ubd_request(struct request_queue *q)
 					(unsigned long long)dev->rq_pos << 9,
 					sg->offset, sg->length, sg_page(sg));
 
-			n = os_write_file(thread_fd, &io_req,
-					  sizeof(struct io_thread_req *));
-			if(n != sizeof(struct io_thread_req *)){
-				if(n != -EAGAIN)
-					printk("write to io thread failed, "
-					       "errno = %d\n", -n);
-				else if(list_empty(&dev->restart))
-					list_add(&dev->restart, &restart);
-				kfree(io_req);
+			if (submit_request(io_req, dev) == false)
 				return;
-			}
 
 			dev->rq_pos += sg->length >> 9;
 			dev->start_sg++;
@@ -1367,6 +1401,17 @@ static void do_io(struct io_thread_req *req)
 	int err;
 	__u64 off;
 
+	if (req->op == UBD_FLUSH) {
+		/* fds[0] is always either the rw image or our cow file */
+		n = os_sync_file(req->fds[0]);
+		if (n != 0) {
+			printk("do_io - sync failed err = %d "
+			       "fd = %d\n", -n, req->fds[0]);
+			req->error = 1;
+		}
+		return;
+	}
+
 	nsectors = req->length / req->sectorsize;
 	start = 0;
 	do {
@@ -1431,7 +1476,8 @@ int io_thread(void *arg)
 	struct io_thread_req *req;
 	int n;
 
-	ignore_sigwinch_sig();
+	os_fix_helper_signals();
+
 	while(1){
 		n = os_read_file(kernel_fd, &req,
 				 sizeof(struct io_thread_req *));

arch/um/drivers/ubd_user.c

@@ -21,11 +21,6 @@
 #include "ubd.h"
 #include <os.h>
 
-void ignore_sigwinch_sig(void)
-{
-	signal(SIGWINCH, SIG_IGN);
-}
-
 int start_io_thread(unsigned long sp, int *fd_out)
 {
 	int pid, fds[2], err;

arch/um/include/shared/os.h

@@ -141,6 +141,7 @@ extern int os_seek_file(int fd, unsigned long long offset);
 extern int os_open_file(const char *file, struct openflags flags, int mode);
 extern int os_read_file(int fd, void *buf, int len);
 extern int os_write_file(int fd, const void *buf, int count);
+extern int os_sync_file(int fd);
 extern int os_file_size(const char *file, unsigned long long *size_out);
 extern int os_file_modtime(const char *file, unsigned long *modtime);
 extern int os_pipe(int *fd, int stream, int close_on_exec);
@@ -200,6 +201,7 @@ extern int os_unmap_memory(void *addr, int len);
 extern int os_drop_memory(void *addr, int length);
 extern int can_drop_memory(void);
 extern void os_flush_stdout(void);
+extern int os_mincore(void *addr, unsigned long len);
 
 /* execvp.c */
 extern int execvp_noalloc(char *buf, const char *file, char *const argv[]);
@@ -233,6 +235,7 @@ extern void setup_machinename(char *machine_out);
 extern void setup_hostinfo(char *buf, int len);
 extern void os_dump_core(void) __attribute__ ((noreturn));
 extern void um_early_printk(const char *s, unsigned int n);
+extern void os_fix_helper_signals(void);
 
 /* time.c */
 extern void idle_sleep(unsigned long long nsecs);

arch/um/kernel/Makefile

@@ -13,7 +13,7 @@ clean-files :=
 obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
 	physmem.o process.o ptrace.o reboot.o sigio.o \
 	signal.o smp.o syscall.o sysrq.o time.o tlb.o trap.o \
-	um_arch.o umid.o skas/
+	um_arch.o umid.o maccess.o skas/
 
 obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
 obj-$(CONFIG_GPROF)	+= gprof_syms.o

arch/um/kernel/irq.c

@@ -337,6 +337,8 @@ static struct irq_chip normal_irq_type = {
 	.irq_disable = dummy,
 	.irq_enable = dummy,
 	.irq_ack = dummy,
+	.irq_mask = dummy,
+	.irq_unmask = dummy,
 };
 
 static struct irq_chip SIGVTALRM_irq_type = {
@@ -344,6 +346,8 @@ static struct irq_chip SIGVTALRM_irq_type = {
 	.irq_disable = dummy,
 	.irq_enable = dummy,
 	.irq_ack = dummy,
+	.irq_mask = dummy,
+	.irq_unmask = dummy,
 };
 
 void __init init_IRQ(void)

arch/um/kernel/maccess.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2013 Richard Weinberger <richrd@nod.at>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <os.h>
+
+long probe_kernel_read(void *dst, const void *src, size_t size)
+{
+	void *psrc = (void *)rounddown((unsigned long)src, PAGE_SIZE);
+
+	if ((unsigned long)src < PAGE_SIZE || size <= 0)
+		return -EFAULT;
+
+	if (os_mincore(psrc, size + src - psrc) <= 0)
+		return -EFAULT;
+
+	return __probe_kernel_read(dst, src, size);
+}

arch/um/os-Linux/aio.c

@@ -104,8 +104,7 @@ static int aio_thread(void *arg)
 	struct io_event event;
 	int err, n, reply_fd;
 
-	signal(SIGWINCH, SIG_IGN);
-
+	os_fix_helper_signals();
 	while (1) {
 		n = io_getevents(ctx, 1, 1, &event, NULL);
 		if (n < 0) {
@@ -173,7 +172,7 @@ static int not_aio_thread(void *arg)
 	struct aio_thread_reply reply;
 	int err;
 
-	signal(SIGWINCH, SIG_IGN);
+	os_fix_helper_signals();
 	while (1) {
 		err = read(aio_req_fd_r, &req, sizeof(req));
 		if (err != sizeof(req)) {

arch/um/os-Linux/file.c

@@ -266,6 +266,15 @@ int os_write_file(int fd, const void *buf, int len)
 	return n;
 }
 
+int os_sync_file(int fd)
+{
+	int n = fsync(fd);
+
+	if (n < 0)
+		return -errno;
+	return n;
+}
+
 int os_file_size(const char *file, unsigned long long *size_out)
 {
 	struct uml_stat buf;

arch/um/os-Linux/main.c

@@ -123,6 +123,8 @@ int __init main(int argc, char **argv, char **envp)
 
 	setup_env_path();
 
+	setsid();
+
 	new_argv = malloc((argc + 1) * sizeof(char *));
 	if (new_argv == NULL) {
 		perror("Mallocing argv");

arch/um/os-Linux/process.c

@@ -4,6 +4,7 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>
@@ -232,6 +233,57 @@ out:
 	return ok;
 }
 
+static int os_page_mincore(void *addr)
+{
+	char vec[2];
+	int ret;
+
+	ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
+	if (ret < 0) {
+		if (errno == ENOMEM || errno == EINVAL)
+			return 0;
+		else
+			return -errno;
+	}
+
+	return vec[0] & 1;
+}
+
+int os_mincore(void *addr, unsigned long len)
+{
+	char *vec;
+	int ret, i;
+
+	if (len <= UM_KERN_PAGE_SIZE)
+		return os_page_mincore(addr);
+
+	vec = calloc(1, (len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE);
+	if (!vec)
+		return -ENOMEM;
+
+	ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
+	if (ret < 0) {
+		if (errno == ENOMEM || errno == EINVAL)
+			ret = 0;
+		else
+			ret = -errno;
+
+		goto out;
+	}
+
+	for (i = 0; i < ((len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); i++) {
+		if (!(vec[i] & 1)) {
+			ret = 0;
+			goto out;
+		}
+	}
+
+	ret = 1;
+out:
+	free(vec);
+	return ret;
+}
+
 void init_new_thread_signals(void)
 {
 	set_handler(SIGSEGV);
@@ -242,5 +294,4 @@ void init_new_thread_signals(void)
 	signal(SIGHUP, SIG_IGN);
 	set_handler(SIGIO);
 	signal(SIGWINCH, SIG_IGN);
-	signal(SIGTERM, SIG_DFL);
 }

arch/um/os-Linux/sigio.c

@@ -55,7 +55,7 @@ static int write_sigio_thread(void *unused)
 	int i, n, respond_fd;
 	char c;
 
-	signal(SIGWINCH, SIG_IGN);
+	os_fix_helper_signals();
 	fds = &current_poll;
 	while (1) {
 		n = poll(fds->poll, fds->used, -1);

arch/um/os-Linux/util.c

@@ -94,6 +94,16 @@ static inline void __attribute__ ((noreturn)) uml_abort(void)
 			exit(127);
 }
 
+/*
+ * UML helper threads must not handle SIGWINCH/INT/TERM
+ */
+void os_fix_helper_signals(void)
+{
+	signal(SIGWINCH, SIG_IGN);
+	signal(SIGINT, SIG_DFL);
+	signal(SIGTERM, SIG_DFL);
+}
+
 void os_dump_core(void)
 {
 	int pid;

arch/x86/um/os-Linux/prctl.c

@@ -4,7 +4,7 @@
  */
 
 #include <sys/ptrace.h>
-#include <linux/ptrace.h>
+#include <asm/ptrace.h>
 
 int os_arch_prctl(int pid, int code, unsigned long *addr)
 {

fs/hostfs/hostfs_kern.c

@@ -361,6 +361,13 @@ retry:
 	return 0;
 }
 
+static int hostfs_file_release(struct inode *inode, struct file *file)
+{
+	filemap_write_and_wait(inode->i_mapping);
+
+	return 0;
+}
+
 int hostfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
 	struct inode *inode = file->f_mapping->host;
@@ -386,7 +393,7 @@ static const struct file_operations hostfs_file_fops = {
 	.write		= do_sync_write,
 	.mmap		= generic_file_mmap,
 	.open		= hostfs_file_open,
-	.release	= NULL,
+	.release	= hostfs_file_release,
 	.fsync		= hostfs_fsync,
 };