stream_open related patches for Linux 5.2

https://lore.kernel.org/linux-fsdevel/CAHk-=wg1tFzcaX2v9Z91vPJiBR486ddW5MtgDL02-fOen2F0Aw@mail.gmail.com/T/#m5b2d9ad3aeacea4bd6aa1964468ac074bf3aa5bf
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Merge tag 'stream_open-5.2' of https://lab.nexedi.com/kirr/linux

Pull stream_open conversion from Kirill Smelkov:

 - remove unnecessary double nonseekable_open from drivers/char/dtlk.c
   as noticed by Pavel Machek while reviewing nonseekable_open ->
   stream_open mass conversion.

 - the mass conversion patch promised in commit 10dce8af34 ("fs:
   stream_open - opener for stream-like files so that read and write can
   run simultaneously without deadlock") and is automatically generated
   by running

        $ make coccicheck MODE=patch COCCI=scripts/coccinelle/api/stream_open.cocci

   I've verified each generated change manually - that it is correct to
   convert - and each other nonseekable_open instance left - that it is
   either not correct to convert there, or that it is not converted due
   to current stream_open.cocci limitations. More details on this in the
   patch.

 - finally, change VFS to pass ppos=NULL into .read/.write for files
   that declare themselves streams. It was suggested by Rasmus Villemoes
   and makes sure that if ppos starts to be erroneously used in a stream
   file, such bug won't go unnoticed and will produce an oops instead of
   creating illusion of position change being taken into account.

   Note: this patch does not conflict with "fuse: Add FOPEN_STREAM to
   use stream_open()" that will be hopefully coming via FUSE tree,
   because fs/fuse/ uses new-style .read_iter/.write_iter, and for these
   accessors position is still passed as non-pointer kiocb.ki_pos .

* tag 'stream_open-5.2' of https://lab.nexedi.com/kirr/linux:
  vfs: pass ppos=NULL to .read()/.write() of FMODE_STREAM files
  *: convert stream-like files from nonseekable_open -> stream_open
  dtlk: remove double call to nonseekable_open

arch/powerpc/platforms/52xx/mpc52xx_gpt.c

@@ -628,7 +628,7 @@ static int mpc52xx_wdt_open(struct inode *inode, struct file *file)
 	}
 
 	file->private_data = mpc52xx_gpt_wdt;
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int mpc52xx_wdt_release(struct inode *inode, struct file *file)

arch/powerpc/platforms/cell/spufs/file.c

@@ -588,7 +588,7 @@ static int spufs_pipe_open(struct inode *inode, struct file *file)
 	struct spufs_inode_info *i = SPUFS_I(inode);
 	file->private_data = i->i_ctx;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /*

arch/um/drivers/harddog_kern.c

@@ -85,7 +85,7 @@ static int harddog_open(struct inode *inode, struct file *file)
 	timer_alive = 1;
 	spin_unlock(&lock);
 	mutex_unlock(&harddog_mutex);
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 err:
 	spin_unlock(&lock);
 	mutex_unlock(&harddog_mutex);

arch/x86/kernel/cpu/microcode/core.c

@@ -428,7 +428,7 @@ static int do_microcode_update(const void __user *buf, size_t size)
 
 static int microcode_open(struct inode *inode, struct file *file)
 {
-	return capable(CAP_SYS_RAWIO) ? nonseekable_open(inode, file) : -EPERM;
+	return capable(CAP_SYS_RAWIO) ? stream_open(inode, file) : -EPERM;
 }
 
 static ssize_t microcode_write(struct file *file, const char __user *buf,

drivers/char/ds1620.c

@@ -212,7 +212,7 @@ static void ds1620_read_state(struct therm *therm)
 
 static int ds1620_open(struct inode *inode, struct file *file)
 {
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static ssize_t

drivers/char/dtlk.c

@@ -298,12 +298,11 @@ static int dtlk_open(struct inode *inode, struct file *file)
 {
 	TRACE_TEXT("(dtlk_open");
 
-	nonseekable_open(inode, file);
 	switch (iminor(inode)) {
 	case DTLK_MINOR:
 		if (dtlk_busy)
 			return -EBUSY;
-		return nonseekable_open(inode, file);
+		return stream_open(inode, file);
 
 	default:
 		return -ENXIO;

drivers/char/ipmi/ipmi_watchdog.c

@@ -837,7 +837,7 @@ static int ipmi_open(struct inode *ino, struct file *filep)
 		 * first heartbeat.
 		 */
 		ipmi_start_timer_on_heartbeat = 1;
-		return nonseekable_open(ino, filep);
+		return stream_open(ino, filep);
 
 	default:
 		return (-ENODEV);

drivers/char/pcmcia/cm4000_cs.c

@@ -1682,7 +1682,7 @@ static int cmm_open(struct inode *inode, struct file *filp)
 	link->open = 1;		/* only one open per device */
 
 	DEBUGP(2, dev, "<- cmm_open\n");
-	ret = nonseekable_open(inode, filp);
+	ret = stream_open(inode, filp);
 out:
 	mutex_unlock(&cmm_mutex);
 	return ret;

drivers/char/pcmcia/scr24x_cs.c

@@ -92,7 +92,7 @@ static int scr24x_open(struct inode *inode, struct file *filp)
 	kref_get(&dev->refcnt);
 	filp->private_data = dev;
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int scr24x_release(struct inode *inode, struct file *filp)

drivers/char/tb0219.c

@@ -243,7 +243,7 @@ static int tanbac_tb0219_open(struct inode *inode, struct file *file)
 	case 16 ... 23:
 	case 32 ... 39:
 	case 48 ... 55:
-		return nonseekable_open(inode, file);
+		return stream_open(inode, file);
 	default:
 		break;
 	}

drivers/firewire/nosy.c

@@ -303,7 +303,7 @@ nosy_open(struct inode *inode, struct file *file)
 
 	file->private_data = client;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 fail:
 	kfree(client);
 	lynx_put(lynx);

drivers/gnss/core.c

@@ -42,7 +42,7 @@ static int gnss_open(struct inode *inode, struct file *file)
 
 	get_device(&gdev->dev);
 
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 	file->private_data = gdev;
 
 	down_write(&gdev->rwsem);

drivers/hid/uhid.c

@@ -632,7 +632,7 @@ static int uhid_char_open(struct inode *inode, struct file *file)
 	INIT_WORK(&uhid->worker, uhid_device_add_worker);
 
 	file->private_data = uhid;
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	return 0;
 }

drivers/hwmon/fschmd.c

@@ -837,7 +837,7 @@ static int watchdog_open(struct inode *inode, struct file *filp)
 	watchdog_trigger(data);
 	filp->private_data = data;
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int watchdog_release(struct inode *inode, struct file *filp)

drivers/hwmon/w83793.c

@@ -1341,7 +1341,7 @@ static int watchdog_open(struct inode *inode, struct file *filp)
 	/* Store pointer to data into filp's private data */
 	filp->private_data = data;
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int watchdog_close(struct inode *inode, struct file *filp)

drivers/infiniband/core/ucm.c

@@ -1175,7 +1175,7 @@ static int ib_ucm_open(struct inode *inode, struct file *filp)
 	file->filp = filp;
 	file->device = container_of(inode->i_cdev, struct ib_ucm_device, cdev);
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int ib_ucm_close(struct inode *inode, struct file *filp)

drivers/infiniband/core/ucma.c

@@ -1744,7 +1744,7 @@ static int ucma_open(struct inode *inode, struct file *filp)
 	filp->private_data = file;
 	file->filp = filp;
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int ucma_close(struct inode *inode, struct file *filp)

drivers/infiniband/core/user_mad.c

@@ -985,7 +985,7 @@ static int ib_umad_open(struct inode *inode, struct file *filp)
 
 	list_add_tail(&file->port_list, &port->file_list);
 
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 out:
 	mutex_unlock(&port->file_mutex);
 	return ret;

drivers/infiniband/core/uverbs_main.c

@@ -1132,7 +1132,7 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
 
 	setup_ufile_idr_uobject(file);
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 
 err_module:
 	module_put(ib_dev->owner);

drivers/input/evdev.c

@@ -524,7 +524,7 @@ static int evdev_open(struct inode *inode, struct file *file)
 		goto err_free_client;
 
 	file->private_data = client;
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	return 0;
 

drivers/input/joydev.c

@@ -279,7 +279,7 @@ static int joydev_open(struct inode *inode, struct file *file)
 		goto err_free_client;
 
 	file->private_data = client;
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	return 0;
 

drivers/input/misc/uinput.c

@@ -398,7 +398,7 @@ static int uinput_open(struct inode *inode, struct file *file)
 	newdev->state = UIST_NEW_DEVICE;
 
 	file->private_data = newdev;
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	return 0;
 }

drivers/isdn/capi/capi.c

@@ -960,7 +960,7 @@ static int capi_open(struct inode *inode, struct file *file)
 	list_add_tail(&cdev->list, &capidev_list);
 	mutex_unlock(&capidev_list_lock);
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int capi_release(struct inode *inode, struct file *file)

drivers/leds/uleds.c

@@ -74,7 +74,7 @@ static int uleds_open(struct inode *inode, struct file *file)
 	udev->state = ULEDS_STATE_UNKNOWN;
 
 	file->private_data = udev;
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	return 0;
 }

drivers/media/rc/lirc_dev.c

@@ -195,7 +195,7 @@ static int ir_lirc_open(struct inode *inode, struct file *file)
 	list_add(&fh->list, &dev->lirc_fh);
 	spin_unlock_irqrestore(&dev->lirc_fh_lock, flags);
 
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	return 0;
 out_kfifo:

drivers/pci/switch/switchtec.c

@@ -390,7 +390,7 @@ static int switchtec_dev_open(struct inode *inode, struct file *filp)
 		return PTR_ERR(stuser);
 
 	filp->private_data = stuser;
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 
 	dev_dbg(&stdev->dev, "%s: %p\n", __func__, stuser);
 

drivers/platform/chrome/cros_ec_debugfs.c

@@ -132,7 +132,7 @@ static int cros_ec_console_log_open(struct inode *inode, struct file *file)
 {
 	file->private_data = inode->i_private;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static ssize_t cros_ec_console_log_read(struct file *file, char __user *buf,

drivers/rtc/rtc-ds1374.c

@@ -467,7 +467,7 @@ static int ds1374_wdt_open(struct inode *inode, struct file *file)
 		 */
 		wdt_is_open = 1;
 		mutex_unlock(&ds1374->mutex);
-		return nonseekable_open(inode, file);
+		return stream_open(inode, file);
 	}
 	return -ENODEV;
 }

drivers/rtc/rtc-m41t80.c

@@ -802,7 +802,7 @@ static int wdt_open(struct inode *inode, struct file *file)
 		 */
 		wdt_is_open = 1;
 		mutex_unlock(&m41t80_rtc_mutex);
-		return nonseekable_open(inode, file);
+		return stream_open(inode, file);
 	}
 	return -ENODEV;
 }

drivers/s390/char/fs3270.c

@@ -486,7 +486,7 @@ fs3270_open(struct inode *inode, struct file *filp)
 		raw3270_del_view(&fp->view);
 		goto out;
 	}
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 	filp->private_data = fp;
 out:
 	mutex_unlock(&fs3270_mutex);

drivers/s390/char/tape_char.c

@@ -290,7 +290,7 @@ tapechar_open (struct inode *inode, struct file *filp)
 	rc = tape_open(device);
 	if (rc == 0) {
 		filp->private_data = device;
-		nonseekable_open(inode, filp);
+		stream_open(inode, filp);
 	} else
 		tape_put_device(device);
 

drivers/s390/char/zcore.c

@@ -191,7 +191,7 @@ static ssize_t zcore_reipl_write(struct file *filp, const char __user *buf,
 
 static int zcore_reipl_open(struct inode *inode, struct file *filp)
 {
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int zcore_reipl_release(struct inode *inode, struct file *filp)

drivers/s390/crypto/zcrypt_api.c

@@ -525,7 +525,7 @@ static int zcrypt_open(struct inode *inode, struct file *filp)
 	filp->private_data = (void *) perms;
 
 	atomic_inc(&zcrypt_open_count);
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 /**

drivers/spi/spidev.c

@@ -593,7 +593,7 @@ static int spidev_open(struct inode *inode, struct file *filp)
 
 	spidev->users++;
 	filp->private_data = spidev;
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 
 	mutex_unlock(&device_list_lock);
 	return 0;

drivers/staging/pi433/pi433_if.c

@@ -971,7 +971,7 @@ static int pi433_open(struct inode *inode, struct file *filp)
 
 	/* instance data as context */
 	filp->private_data = instance;
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 
 	return 0;
 }

drivers/usb/misc/ldusb.c

@@ -307,7 +307,7 @@ static int ld_usb_open(struct inode *inode, struct file *file)
 	int retval;
 	struct usb_interface *interface;
 
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 	subminor = iminor(inode);
 
 	interface = usb_find_interface(&ld_usb_driver, subminor);

drivers/watchdog/acquirewdt.c

@@ -200,7 +200,7 @@ static int acq_open(struct inode *inode, struct file *file)
 
 	/* Activate */
 	acq_keepalive();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int acq_close(struct inode *inode, struct file *file)

drivers/watchdog/advantechwdt.c

@@ -199,7 +199,7 @@ static int advwdt_open(struct inode *inode, struct file *file)
 	 */
 
 	advwdt_ping();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int advwdt_close(struct inode *inode, struct file *file)

drivers/watchdog/alim1535_wdt.c

@@ -249,7 +249,7 @@ static int ali_open(struct inode *inode, struct file *file)
 
 	/* Activate */
 	ali_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /*

drivers/watchdog/alim7101_wdt.c

@@ -214,7 +214,7 @@ static int fop_open(struct inode *inode, struct file *file)
 		return -EBUSY;
 	/* Good, fire up the show */
 	wdt_startup();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int fop_close(struct inode *inode, struct file *file)

drivers/watchdog/ar7_wdt.c

@@ -163,7 +163,7 @@ static int ar7_wdt_open(struct inode *inode, struct file *file)
 	ar7_wdt_enable_wdt();
 	expect_close = 0;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int ar7_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/at91rm9200_wdt.c

@@ -110,7 +110,7 @@ static int at91_wdt_open(struct inode *inode, struct file *file)
 		return -EBUSY;
 
 	at91_wdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /*

drivers/watchdog/ath79_wdt.c

@@ -132,7 +132,7 @@ static int ath79_wdt_open(struct inode *inode, struct file *file)
 	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
 	ath79_wdt_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int ath79_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/bcm63xx_wdt.c

@@ -116,7 +116,7 @@ static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
 		return -EBUSY;
 
 	bcm63xx_wdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/cpu5wdt.c

@@ -140,7 +140,7 @@ static int cpu5wdt_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(0, &cpu5wdt_device.inuse))
 		return -EBUSY;
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int cpu5wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/cpwd.c

@@ -394,7 +394,7 @@ static int cpwd_open(struct inode *inode, struct file *f)
 
 	mutex_unlock(&cpwd_mutex);
 
-	return nonseekable_open(inode, f);
+	return stream_open(inode, f);
 }
 
 static int cpwd_release(struct inode *inode, struct file *file)

drivers/watchdog/eurotechwdt.c

@@ -316,7 +316,7 @@ static int eurwdt_open(struct inode *inode, struct file *file)
 	eurwdt_timeout = WDT_TIMEOUT;	/* initial timeout */
 	/* Activate the WDT */
 	eurwdt_activate_timer();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**

drivers/watchdog/f71808e_wdt.c

@@ -525,7 +525,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
 		__module_get(THIS_MODULE);
 
 	watchdog.expect_close = 0;
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int watchdog_release(struct inode *inode, struct file *file)

drivers/watchdog/gef_wdt.c

@@ -229,7 +229,7 @@ static int gef_wdt_open(struct inode *inode, struct file *file)
 
 	gef_wdt_handler_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int gef_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/geodewdt.c

@@ -92,7 +92,7 @@ static int geodewdt_open(struct inode *inode, struct file *file)
 		__module_get(THIS_MODULE);
 
 	geodewdt_ping();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int geodewdt_release(struct inode *inode, struct file *file)

drivers/watchdog/ib700wdt.c

@@ -238,7 +238,7 @@ static int ibwdt_open(struct inode *inode, struct file *file)
 
 	/* Activate */
 	ibwdt_ping();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int ibwdt_close(struct inode *inode, struct file *file)

drivers/watchdog/ibmasr.c

@@ -323,7 +323,7 @@ static int asr_open(struct inode *inode, struct file *file)
 	asr_toggle();
 	asr_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int asr_release(struct inode *inode, struct file *file)

drivers/watchdog/indydog.c

@@ -77,7 +77,7 @@ static int indydog_open(struct inode *inode, struct file *file)
 
 	pr_info("Started watchdog timer\n");
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int indydog_release(struct inode *inode, struct file *file)

drivers/watchdog/intel_scu_watchdog.c

@@ -304,7 +304,7 @@ static int intel_scu_open(struct inode *inode, struct file *file)
 	if (watchdog_device.driver_closed)
 		return -EPERM;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int intel_scu_release(struct inode *inode, struct file *file)

drivers/watchdog/iop_wdt.c

@@ -101,7 +101,7 @@ static int iop_wdt_open(struct inode *inode, struct file *file)
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 	wdt_enable();
 	set_bit(WDT_ENABLED, &wdt_status);
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len,

drivers/watchdog/it8712f_wdt.c

@@ -327,7 +327,7 @@ static int it8712f_wdt_open(struct inode *inode, struct file *file)
 	ret = it8712f_wdt_enable();
 	if (ret)
 		return ret;
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int it8712f_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/ixp4xx_wdt.c

@@ -65,7 +65,7 @@ static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
 
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 	wdt_enable();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static ssize_t

drivers/watchdog/ks8695_wdt.c

@@ -142,7 +142,7 @@ static int ks8695_wdt_open(struct inode *inode, struct file *file)
 		return -EBUSY;
 
 	ks8695_wdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /*

drivers/watchdog/m54xx_wdt.c

@@ -85,7 +85,7 @@ static int m54xx_wdt_open(struct inode *inode, struct file *file)
 
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 	wdt_enable();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static ssize_t m54xx_wdt_write(struct file *file, const char *data,

drivers/watchdog/machzwd.c

@@ -333,7 +333,7 @@ static int zf_open(struct inode *inode, struct file *file)
 	if (nowayout)
 		__module_get(THIS_MODULE);
 	zf_timer_on();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int zf_close(struct inode *inode, struct file *file)

drivers/watchdog/mixcomwd.c

@@ -150,7 +150,7 @@ static int mixcomwd_open(struct inode *inode, struct file *file)
 			mixcomwd_timer_alive = 0;
 		}
 	}
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int mixcomwd_release(struct inode *inode, struct file *file)

drivers/watchdog/mtx-1_wdt.c

@@ -118,7 +118,7 @@ static int mtx1_wdt_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
 		return -EBUSY;
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 

drivers/watchdog/mv64x60_wdt.c

@@ -133,7 +133,7 @@ static int mv64x60_wdt_open(struct inode *inode, struct file *file)
 
 	mv64x60_wdt_handler_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int mv64x60_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/nuc900_wdt.c

@@ -131,7 +131,7 @@ static int nuc900_wdt_open(struct inode *inode, struct file *file)
 
 	nuc900_wdt_start();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int nuc900_wdt_close(struct inode *inode, struct file *file)

drivers/watchdog/nv_tco.c

@@ -161,7 +161,7 @@ static int nv_tco_open(struct inode *inode, struct file *file)
 	/* Reload and activate timer */
 	tco_timer_keepalive();
 	tco_timer_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int nv_tco_release(struct inode *inode, struct file *file)

drivers/watchdog/pc87413_wdt.c

@@ -286,7 +286,7 @@ static int pc87413_open(struct inode *inode, struct file *file)
 
 	pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**

drivers/watchdog/pcwd.c

@@ -695,7 +695,7 @@ static int pcwd_open(struct inode *inode, struct file *file)
 	/* Activate */
 	pcwd_start();
 	pcwd_keepalive();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int pcwd_close(struct inode *inode, struct file *file)
@@ -734,7 +734,7 @@ static int pcwd_temp_open(struct inode *inode, struct file *file)
 	if (!pcwd_private.supports_temp)
 		return -ENODEV;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int pcwd_temp_close(struct inode *inode, struct file *file)

drivers/watchdog/pcwd_pci.c

@@ -578,7 +578,7 @@ static int pcipcwd_open(struct inode *inode, struct file *file)
 	/* Activate */
 	pcipcwd_start();
 	pcipcwd_keepalive();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int pcipcwd_release(struct inode *inode, struct file *file)
@@ -620,7 +620,7 @@ static int pcipcwd_temp_open(struct inode *inode, struct file *file)
 	if (!pcipcwd_private.supports_temp)
 		return -ENODEV;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int pcipcwd_temp_release(struct inode *inode, struct file *file)

drivers/watchdog/pcwd_usb.c

@@ -485,7 +485,7 @@ static int usb_pcwd_open(struct inode *inode, struct file *file)
 	/* Activate */
 	usb_pcwd_start(usb_pcwd_device);
 	usb_pcwd_keepalive(usb_pcwd_device);
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int usb_pcwd_release(struct inode *inode, struct file *file)
@@ -524,7 +524,7 @@ static ssize_t usb_pcwd_temperature_read(struct file *file, char __user *data,
 
 static int usb_pcwd_temperature_open(struct inode *inode, struct file *file)
 {
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int usb_pcwd_temperature_release(struct inode *inode, struct file *file)

drivers/watchdog/pika_wdt.c

@@ -118,7 +118,7 @@ static int pikawdt_open(struct inode *inode, struct file *file)
 
 	pikawdt_start();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /*

drivers/watchdog/pnx833x_wdt.c

@@ -116,7 +116,7 @@ static int pnx833x_wdt_open(struct inode *inode, struct file *file)
 
 	pr_info("Started watchdog timer\n");
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int pnx833x_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/rc32434_wdt.c

@@ -150,7 +150,7 @@ static int rc32434_wdt_open(struct inode *inode, struct file *file)
 	rc32434_wdt_start();
 	rc32434_wdt_ping();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int rc32434_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/rdc321x_wdt.c

@@ -142,7 +142,7 @@ static int rdc321x_wdt_open(struct inode *inode, struct file *file)
 	if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
 		return -EBUSY;
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int rdc321x_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/riowd.c

@@ -76,7 +76,7 @@ static void riowd_writereg(struct riowd *p, u8 val, int index)
 
 static int riowd_open(struct inode *inode, struct file *filp)
 {
-	nonseekable_open(inode, filp);
+	stream_open(inode, filp);
 	return 0;
 }
 

drivers/watchdog/sa1100_wdt.c

@@ -59,7 +59,7 @@ static int sa1100dog_open(struct inode *inode, struct file *file)
 	writel_relaxed(OSSR_M3, OSSR);
 	writel_relaxed(OWER_WME, OWER);
 	writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER);
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /*

drivers/watchdog/sb_wdog.c

@@ -105,7 +105,7 @@ static const struct watchdog_info ident = {
  */
 static int sbwdog_open(struct inode *inode, struct file *file)
 {
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 	if (test_and_set_bit(0, &sbwdog_gate))
 		return -EBUSY;
 	__module_get(THIS_MODULE);

drivers/watchdog/sbc60xxwdt.c

@@ -208,7 +208,7 @@ static int fop_open(struct inode *inode, struct file *file)
 
 	/* Good, fire up the show */
 	wdt_startup();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int fop_close(struct inode *inode, struct file *file)

drivers/watchdog/sbc7240_wdt.c

@@ -136,7 +136,7 @@ static int fop_open(struct inode *inode, struct file *file)
 
 	wdt_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int fop_close(struct inode *inode, struct file *file)

drivers/watchdog/sbc8360.c

@@ -271,7 +271,7 @@ static int sbc8360_open(struct inode *inode, struct file *file)
 	/* Activate and ping once to start the countdown */
 	sbc8360_activate();
 	sbc8360_ping();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int sbc8360_close(struct inode *inode, struct file *file)

drivers/watchdog/sbc_epx_c3.c

@@ -78,7 +78,7 @@ static int epx_c3_open(struct inode *inode, struct file *file)
 	epx_c3_alive = 1;
 	pr_info("Started watchdog timer\n");
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int epx_c3_release(struct inode *inode, struct file *file)

drivers/watchdog/sbc_fitpc2_wdt.c

@@ -75,7 +75,7 @@ static int fitpc2_wdt_open(struct inode *inode, struct file *file)
 
 	wdt_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static ssize_t fitpc2_wdt_write(struct file *file, const char *data,

drivers/watchdog/sc1200wdt.c

@@ -178,7 +178,7 @@ static int sc1200wdt_open(struct inode *inode, struct file *file)
 	sc1200wdt_start();
 	pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 

drivers/watchdog/sc520_wdt.c

@@ -258,7 +258,7 @@ static int fop_open(struct inode *inode, struct file *file)
 
 	/* Good, fire up the show */
 	wdt_startup();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int fop_close(struct inode *inode, struct file *file)

drivers/watchdog/sch311x_wdt.c

@@ -316,7 +316,7 @@ static int sch311x_wdt_open(struct inode *inode, struct file *file)
 	 *	Activate
 	 */
 	sch311x_wdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int sch311x_wdt_close(struct inode *inode, struct file *file)

drivers/watchdog/scx200_wdt.c

@@ -102,7 +102,7 @@ static int scx200_wdt_open(struct inode *inode, struct file *file)
 		return -EBUSY;
 	scx200_wdt_enable();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int scx200_wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/smsc37b787_wdt.c

@@ -366,7 +366,7 @@ static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
 	pr_info("Watchdog enabled. Timeout set to %d %s\n",
 		timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /* close => shut off the timer */

drivers/watchdog/w83877f_wdt.c

@@ -224,7 +224,7 @@ static int fop_open(struct inode *inode, struct file *file)
 
 	/* Good, fire up the show */
 	wdt_startup();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int fop_close(struct inode *inode, struct file *file)

drivers/watchdog/w83977f_wdt.c

@@ -298,7 +298,7 @@ static int wdt_open(struct inode *inode, struct file *file)
 		__module_get(THIS_MODULE);
 
 	wdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int wdt_release(struct inode *inode, struct file *file)

drivers/watchdog/wafer5823wdt.c

@@ -197,7 +197,7 @@ static int wafwdt_open(struct inode *inode, struct file *file)
 	 *      Activate
 	 */
 	wafwdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int wafwdt_close(struct inode *inode, struct file *file)

drivers/watchdog/watchdog_dev.c

@@ -825,7 +825,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
 		kref_get(&wd_data->kref);
 
 	/* dev/watchdog is a virtual (and thus non-seekable) filesystem */
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 
 out_mod:
 	module_put(wd_data->wdd->ops->owner);

drivers/watchdog/wdrtas.c

@@ -376,7 +376,7 @@ static int wdrtas_open(struct inode *inode, struct file *file)
 	wdrtas_timer_start();
 	wdrtas_timer_keepalive();
 
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**
@@ -442,7 +442,7 @@ static ssize_t wdrtas_temp_read(struct file *file, char __user *buf,
  */
 static int wdrtas_temp_open(struct inode *inode, struct file *file)
 {
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**

drivers/watchdog/wdt.c

@@ -421,7 +421,7 @@ static int wdt_open(struct inode *inode, struct file *file)
 	 *	Activate
 	 */
 	wdt_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**
@@ -481,7 +481,7 @@ static ssize_t wdt_temp_read(struct file *file, char __user *buf,
 
 static int wdt_temp_open(struct inode *inode, struct file *file)
 {
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**

drivers/watchdog/wdt285.c

@@ -101,7 +101,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
 
 	ret = 0;
 #endif
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 	return ret;
 }
 

drivers/watchdog/wdt977.c

@@ -273,7 +273,7 @@ static int wdt977_open(struct inode *inode, struct file *file)
 		__module_get(THIS_MODULE);
 
 	wdt977_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 static int wdt977_release(struct inode *inode, struct file *file)

drivers/watchdog/wdt_pci.c

@@ -461,7 +461,7 @@ static int wdtpci_open(struct inode *inode, struct file *file)
 	 *	Activate
 	 */
 	wdtpci_start();
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**
@@ -524,7 +524,7 @@ static ssize_t wdtpci_temp_read(struct file *file, char __user *buf,
 
 static int wdtpci_temp_open(struct inode *inode, struct file *file)
 {
-	return nonseekable_open(inode, file);
+	return stream_open(inode, file);
 }
 
 /**

drivers/xen/evtchn.c

@@ -664,7 +664,7 @@ static int evtchn_open(struct inode *inode, struct file *filp)
 
 	filp->private_data = u;
 
-	return nonseekable_open(inode, filp);
+	return stream_open(inode, filp);
 }
 
 static int evtchn_release(struct inode *inode, struct file *filp)

fs/open.c

@@ -1219,8 +1219,9 @@ EXPORT_SYMBOL(nonseekable_open);
 /*
  * stream_open is used by subsystems that want stream-like file descriptors.
  * Such file descriptors are not seekable and don't have notion of position
- * (file.f_pos is always 0). Contrary to file descriptors of other regular
- * files, .read() and .write() can run simultaneously.
+ * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
+ * Contrary to file descriptors of other regular files, .read() and .write()
+ * can run simultaneously.
  *
  * stream_open never fails and is marked to return int so that it could be
  * directly used as file_operations.open .

fs/read_write.c

@@ -365,29 +365,37 @@ SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
 {
 	struct inode *inode;
-	loff_t pos;
 	int retval = -EINVAL;
 
 	inode = file_inode(file);
 	if (unlikely((ssize_t) count < 0))
 		return retval;
-	pos = *ppos;
-	if (unlikely(pos < 0)) {
-		if (!unsigned_offsets(file))
-			return retval;
-		if (count >= -pos) /* both values are in 0..LLONG_MAX */
-			return -EOVERFLOW;
-	} else if (unlikely((loff_t) (pos + count) < 0)) {
-		if (!unsigned_offsets(file))
-			return retval;
+
+	/*
+	 * ranged mandatory locking does not apply to streams - it makes sense
+	 * only for files where position has a meaning.
+	 */
+	if (ppos) {
+		loff_t pos = *ppos;
+
+		if (unlikely(pos < 0)) {
+			if (!unsigned_offsets(file))
+				return retval;
+			if (count >= -pos) /* both values are in 0..LLONG_MAX */
+				return -EOVERFLOW;
+		} else if (unlikely((loff_t) (pos + count) < 0)) {
+			if (!unsigned_offsets(file))
+				return retval;
+		}
+
+		if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
+			retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
+					read_write == READ ? F_RDLCK : F_WRLCK);
+			if (retval < 0)
+				return retval;
+		}
 	}
 
-	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
-		retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
-				read_write == READ ? F_RDLCK : F_WRLCK);
-		if (retval < 0)
-			return retval;
-	}
 	return security_file_permission(file,
 				read_write == READ ? MAY_READ : MAY_WRITE);
 }
@@ -400,12 +408,13 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
 	ssize_t ret;
 
 	init_sync_kiocb(&kiocb, filp);
-	kiocb.ki_pos = *ppos;
+	kiocb.ki_pos = (ppos ? *ppos : 0);
 	iov_iter_init(&iter, READ, &iov, 1, len);
 
 	ret = call_read_iter(filp, &kiocb, &iter);
 	BUG_ON(ret == -EIOCBQUEUED);
-	*ppos = kiocb.ki_pos;
+	if (ppos)
+		*ppos = kiocb.ki_pos;
 	return ret;
 }
 
@@ -468,12 +477,12 @@ static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t
 	ssize_t ret;
 
 	init_sync_kiocb(&kiocb, filp);
-	kiocb.ki_pos = *ppos;
+	kiocb.ki_pos = (ppos ? *ppos : 0);
 	iov_iter_init(&iter, WRITE, &iov, 1, len);
 
 	ret = call_write_iter(filp, &kiocb, &iter);
 	BUG_ON(ret == -EIOCBQUEUED);
-	if (ret > 0)
+	if (ret > 0 && ppos)
 		*ppos = kiocb.ki_pos;
 	return ret;
 }
@@ -558,15 +567,10 @@ ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_
 	return ret;
 }
 
-static inline loff_t file_pos_read(struct file *file)
+/* file_ppos returns &file->f_pos or NULL if file is stream */
+static inline loff_t *file_ppos(struct file *file)
 {
-	return file->f_mode & FMODE_STREAM ? 0 : file->f_pos;
-}
-
-static inline void file_pos_write(struct file *file, loff_t pos)
-{
-	if ((file->f_mode & FMODE_STREAM) == 0)
-		file->f_pos = pos;
+	return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos;
 }
 
 ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
@@ -575,10 +579,14 @@ ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
 	ssize_t ret = -EBADF;
 
 	if (f.file) {
-		loff_t pos = file_pos_read(f.file);
-		ret = vfs_read(f.file, buf, count, &pos);
-		if (ret >= 0)
-			file_pos_write(f.file, pos);
+		loff_t pos, *ppos = file_ppos(f.file);
+		if (ppos) {
+			pos = *ppos;
+			ppos = &pos;
+		}
+		ret = vfs_read(f.file, buf, count, ppos);
+		if (ret >= 0 && ppos)
+			f.file->f_pos = pos;
 		fdput_pos(f);
 	}
 	return ret;
@@ -595,10 +603,14 @@ ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
 	ssize_t ret = -EBADF;
 
 	if (f.file) {
-		loff_t pos = file_pos_read(f.file);
-		ret = vfs_write(f.file, buf, count, &pos);
-		if (ret >= 0)
-			file_pos_write(f.file, pos);
+		loff_t pos, *ppos = file_ppos(f.file);
+		if (ppos) {
+			pos = *ppos;
+			ppos = &pos;
+		}
+		ret = vfs_write(f.file, buf, count, ppos);
+		if (ret >= 0 && ppos)
+			f.file->f_pos = pos;
 		fdput_pos(f);
 	}
 
@@ -673,14 +685,15 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 	ret = kiocb_set_rw_flags(&kiocb, flags);
 	if (ret)
 		return ret;
-	kiocb.ki_pos = *ppos;
+	kiocb.ki_pos = (ppos ? *ppos : 0);
 
 	if (type == READ)
 		ret = call_read_iter(filp, &kiocb, iter);
 	else
 		ret = call_write_iter(filp, &kiocb, iter);
 	BUG_ON(ret == -EIOCBQUEUED);
-	*ppos = kiocb.ki_pos;
+	if (ppos)
+		*ppos = kiocb.ki_pos;
 	return ret;
 }
 
@@ -1013,10 +1026,14 @@ static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
 	ssize_t ret = -EBADF;
 
 	if (f.file) {
-		loff_t pos = file_pos_read(f.file);
-		ret = vfs_readv(f.file, vec, vlen, &pos, flags);
-		if (ret >= 0)
-			file_pos_write(f.file, pos);
+		loff_t pos, *ppos = file_ppos(f.file);
+		if (ppos) {
+			pos = *ppos;
+			ppos = &pos;
+		}
+		ret = vfs_readv(f.file, vec, vlen, ppos, flags);
+		if (ret >= 0 && ppos)
+			f.file->f_pos = pos;
 		fdput_pos(f);
 	}
 
@@ -1033,10 +1050,14 @@ static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
 	ssize_t ret = -EBADF;
 
 	if (f.file) {
-		loff_t pos = file_pos_read(f.file);
-		ret = vfs_writev(f.file, vec, vlen, &pos, flags);
-		if (ret >= 0)
-			file_pos_write(f.file, pos);
+		loff_t pos, *ppos = file_ppos(f.file);
+		if (ppos) {
+			pos = *ppos;
+			ppos = &pos;
+		}
+		ret = vfs_writev(f.file, vec, vlen, ppos, flags);
+		if (ret >= 0 && ppos)
+			f.file->f_pos = pos;
 		fdput_pos(f);
 	}
 

net/batman-adv/icmp_socket.c

@@ -77,7 +77,7 @@ static int batadv_socket_open(struct inode *inode, struct file *file)
 
 	batadv_debugfs_deprecated(file, "");
 
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 
 	socket_client = kmalloc(sizeof(*socket_client), GFP_KERNEL);
 	if (!socket_client) {

net/batman-adv/log.c

@@ -102,7 +102,7 @@ static int batadv_log_open(struct inode *inode, struct file *file)
 	batadv_debugfs_deprecated(file,
 				  "Use tracepoint batadv:batadv_dbg instead\n");
 
-	nonseekable_open(inode, file);
+	stream_open(inode, file);
 	file->private_data = inode->i_private;
 	return 0;
 }