[PATCH] Drop second arg of unregister_chrdev()

[PATCH] Drop second arg of unregister_chrdev()

[Alexey Dobriyan]

* "name" is trivially unused.
* Requirement to pass to unregister function anything but cookie you've
  got from register counterpart is wrong. It creates opportunity to
  diverge, it create opportunity for bugs if enforced:

	/*
	 * XXX(hch): bp->b_count_desired might be incorrect (see
	 * xfs_buf_associate_memory for details),

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

	 *                                        but fortunately
	 * the Linux version of kmem_free ignores the len argument..
	 */
	 kmem_free(bp->b_addr, bp->b_count_desired);
---

 arch/cris/arch-v10/drivers/pcf8563.c     |    2 +-
 arch/cris/arch-v32/drivers/cryptocop.c   |    4 ++--
 arch/cris/arch-v32/drivers/pcf8563.c     |    2 +-
 arch/i386/kernel/cpuid.c                 |    4 ++--
 arch/i386/kernel/msr.c                   |    4 ++--
 arch/mips/kernel/rtlx.c                  |    2 +-
 arch/mips/kernel/vpe.c                   |    2 +-
 arch/mips/sibyte/sb1250/bcm1250_tbprof.c |    2 +-
 arch/sparc64/solaris/socksys.c           |    2 +-
 drivers/block/acsi_slm.c                 |    4 ++--
 drivers/block/aoe/aoechr.c               |    4 ++--
 drivers/block/paride/pg.c                |    4 ++--
 drivers/block/paride/pt.c                |    4 ++--
 drivers/char/drm/drm_drv.c               |    4 ++--
 drivers/char/dsp56k.c                    |    4 ++--
 drivers/char/dtlk.c                      |    2 +-
 drivers/char/ftape/zftape/zftape-init.c  |    2 +-
 drivers/char/ip2/ip2main.c               |    4 ++--
 drivers/char/ipmi/ipmi_devintf.c         |    4 ++--
 drivers/char/istallion.c                 |    2 +-
 drivers/char/lp.c                        |    4 ++--
 drivers/char/mbcs.c                      |    2 +-
 drivers/char/pcmcia/cm4000_cs.c          |    4 ++--
 drivers/char/pcmcia/cm4040_cs.c          |    4 ++--
 drivers/char/ppdev.c                     |    4 ++--
 drivers/char/stallion.c                  |    2 +-
 drivers/char/tipar.c                     |    4 ++--
 drivers/char/tlclk.c                     |    4 ++--
 drivers/char/viotape.c                   |    4 ++--
 drivers/i2c/i2c-dev.c                    |    4 ++--
 drivers/ide/ide-tape.c                   |    2 +-
 drivers/input/input.c                    |    2 +-
 drivers/isdn/capi/capi.c                 |    6 +++---
 drivers/isdn/hardware/eicon/divamnt.c    |    2 +-
 drivers/isdn/hardware/eicon/divasi.c     |    2 +-
 drivers/isdn/hardware/eicon/divasmain.c  |    2 +-
 drivers/isdn/i4l/isdn_common.c           |    6 +++---
 drivers/media/video/videodev.c           |    4 ++--
 drivers/mtd/mtdchar.c                    |    4 ++--
 drivers/net/ppp_generic.c                |    4 ++--
 drivers/net/wan/cosa.c                   |    6 +++---
 drivers/pcmcia/pcmcia_ioctl.c            |    2 +-
 drivers/s390/char/fs3270.c               |    2 +-
 drivers/sbus/char/bpp.c                  |    2 +-
 drivers/sbus/char/vfc_dev.c              |    2 +-
 drivers/scsi/3w-9xxx.c                   |    2 +-
 drivers/scsi/3w-xxxx.c                   |    2 +-
 drivers/scsi/aacraid/linit.c             |    2 +-
 drivers/scsi/ch.c                        |    4 ++--
 drivers/scsi/dpt_i2o.c                   |    2 +-
 drivers/scsi/gdth.c                      |    2 +-
 drivers/scsi/hptiop.c                    |    2 +-
 drivers/scsi/megaraid.c                  |    2 +-
 drivers/scsi/megaraid/megaraid_mm.c      |    2 +-
 drivers/scsi/megaraid/megaraid_sas.c     |    4 ++--
 drivers/scsi/osst.c                      |    2 +-
 drivers/telephony/phonedev.c             |    2 +-
 drivers/usb/core/file.c                  |    2 +-
 drivers/video/fbmem.c                    |    2 +-
 fs/char_dev.c                            |    2 +-
 fs/coda/psdev.c                          |    6 +++---
 include/linux/fs.h                       |    2 +-
 sound/core/sound.c                       |    4 ++--
 sound/sound_core.c                       |    2 +-
 64 files changed, 97 insertions(+), 97 deletions(-)

--- a/arch/cris/arch-v10/drivers/pcf8563.c
+++ b/arch/cris/arch-v10/drivers/pcf8563.c
@@ -180,7 +180,7 @@ err:
 void __exit
 pcf8563_exit(void)
 {
-	if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
+	if (unregister_chrdev(PCF8563_MAJOR) < 0) {
 		printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
 	}
 }
--- a/arch/cris/arch-v32/drivers/cryptocop.c
+++ b/arch/cris/arch-v32/drivers/cryptocop.c
@@ -3476,13 +3476,13 @@ static int init_stream_coprocessor(void)
 
 	err = init_cryptocop();
 	if (err) {
-		(void)unregister_chrdev(CRYPTOCOP_MAJOR, cryptocop_name);
+		(void)unregister_chrdev(CRYPTOCOP_MAJOR);
 		return err;
 	}
 	err = cryptocop_job_queue_init();
 	if (err) {
 		release_cryptocop();
-		(void)unregister_chrdev(CRYPTOCOP_MAJOR, cryptocop_name);
+		(void)unregister_chrdev(CRYPTOCOP_MAJOR);
 		return err;
 	}
 	/* Init the descriptor pool. */
--- a/arch/cris/arch-v32/drivers/pcf8563.c
+++ b/arch/cris/arch-v32/drivers/pcf8563.c
@@ -193,7 +193,7 @@ err:
 void __exit
 pcf8563_exit(void)
 {
-	if (unregister_chrdev(PCF8563_MAJOR, DEVICE_NAME) < 0) {
+	if (unregister_chrdev(PCF8563_MAJOR) < 0) {
 		printk(KERN_INFO "%s: Unable to unregister device.\n", PCF8563_NAME);
 	}
 }
--- a/arch/i386/kernel/cpuid.c
+++ b/arch/i386/kernel/cpuid.c
@@ -222,7 +222,7 @@ out_class:
 	}
 	class_destroy(cpuid_class);
 out_chrdev:
-	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");	
+	unregister_chrdev(CPUID_MAJOR);	
 out:
 	return err;
 }
@@ -234,7 +234,7 @@ static void __exit cpuid_exit(void)
 	for_each_online_cpu(cpu)
 		class_device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
 	class_destroy(cpuid_class);
-	unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
+	unregister_chrdev(CPUID_MAJOR);
 	unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
 }
 
--- a/arch/i386/kernel/msr.c
+++ b/arch/i386/kernel/msr.c
@@ -305,7 +305,7 @@ out_class:
 		class_device_destroy(msr_class, MKDEV(MSR_MAJOR, i));
 	class_destroy(msr_class);
 out_chrdev:
-	unregister_chrdev(MSR_MAJOR, "cpu/msr");
+	unregister_chrdev(MSR_MAJOR);
 out:
 	return err;
 }
@@ -316,7 +316,7 @@ static void __exit msr_exit(void)
 	for_each_online_cpu(cpu)
 		class_device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));
 	class_destroy(msr_class);
-	unregister_chrdev(MSR_MAJOR, "cpu/msr");
+	unregister_chrdev(MSR_MAJOR);
 	unregister_hotcpu_notifier(&msr_class_cpu_notifier);
 }
 
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -529,7 +529,7 @@ static int rtlx_module_init(void)
 
 static void __exit rtlx_module_exit(void)
 {
-	unregister_chrdev(major, module_name);
+	unregister_chrdev(major);
 }
 
 module_init(rtlx_module_init);
--- a/arch/mips/kernel/vpe.c
+++ b/arch/mips/kernel/vpe.c
@@ -1483,7 +1483,7 @@ static void __exit vpe_module_exit(void)
 		}
 	}
 
-	unregister_chrdev(major, module_name);
+	unregister_chrdev(major);
 }
 
 module_init(vpe_module_init);
--- a/arch/mips/sibyte/sb1250/bcm1250_tbprof.c
+++ b/arch/mips/sibyte/sb1250/bcm1250_tbprof.c
@@ -399,7 +399,7 @@ static int __init sbprof_tb_init(void)
 
 static void __exit sbprof_tb_cleanup(void)
 {
-	unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);
+	unregister_chrdev(SBPROF_TB_MAJOR);
 }
 
 module_init(sbprof_tb_init);
--- a/arch/sparc64/solaris/socksys.c
+++ b/arch/sparc64/solaris/socksys.c
@@ -202,6 +202,6 @@ init_socksys(void)
 void
 cleanup_socksys(void)
 {
-	if (unregister_chrdev(30, "socksys"))
+	if (unregister_chrdev(30))
 		printk ("Couldn't unregister socksys character device\n");
 }
--- a/drivers/block/acsi_slm.c
+++ b/drivers/block/acsi_slm.c
@@ -998,7 +998,7 @@ int slm_init( void )
 	
 	if (!(SLMBuffer = atari_stram_alloc( SLM_BUFFER_SIZE, "SLM" ))) {
 		printk( KERN_ERR "Unable to get SLM ST-Ram buffer.\n" );
-		unregister_chrdev( ACSI_MAJOR, "slm" );
+		unregister_chrdev( ACSI_MAJOR );
 		return -ENOMEM;
 	}
 	BufferP = SLMBuffer;
@@ -1026,7 +1026,7 @@ int init_module(void)
 
 void cleanup_module(void)
 {
-	if (unregister_chrdev( ACSI_MAJOR, "slm" ) != 0)
+	if (unregister_chrdev( ACSI_MAJOR ) != 0)
 		printk( KERN_ERR "acsi_slm: cleanup_module failed\n");
 	atari_stram_free( SLMBuffer );
 }
--- a/drivers/block/aoe/aoechr.c
+++ b/drivers/block/aoe/aoechr.c
@@ -257,7 +257,7 @@ aoechr_init(void)
 	spin_lock_init(&emsgs_lock);
 	aoe_class = class_create(THIS_MODULE, "aoe");
 	if (IS_ERR(aoe_class)) {
-		unregister_chrdev(AOE_MAJOR, "aoechr");
+		unregister_chrdev(AOE_MAJOR);
 		return PTR_ERR(aoe_class);
 	}
 	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
@@ -276,6 +276,6 @@ aoechr_exit(void)
 	for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
 		class_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
 	class_destroy(aoe_class);
-	unregister_chrdev(AOE_MAJOR, "aoechr");
+	unregister_chrdev(AOE_MAJOR);
 }
 
--- a/drivers/block/paride/pg.c
+++ b/drivers/block/paride/pg.c
@@ -683,7 +683,7 @@ static int __init pg_init(void)
 	goto out;
 
 out_chrdev:
-	unregister_chrdev(major, "pg");
+	unregister_chrdev(major);
 out:
 	return err;
 }
@@ -698,7 +698,7 @@ static void __exit pg_exit(void)
 			class_device_destroy(pg_class, MKDEV(major, unit));
 	}
 	class_destroy(pg_class);
-	unregister_chrdev(major, name);
+	unregister_chrdev(major);
 
 	for (unit = 0; unit < PG_UNITS; unit++) {
 		struct pg *dev = &devices[unit];
--- a/drivers/block/paride/pt.c
+++ b/drivers/block/paride/pt.c
@@ -980,7 +980,7 @@ static int __init pt_init(void)
 	goto out;
 
 out_chrdev:
-	unregister_chrdev(major, "pt");
+	unregister_chrdev(major);
 out:
 	return err;
 }
@@ -994,7 +994,7 @@ static void __exit pt_exit(void)
 			class_device_destroy(pt_class, MKDEV(major, unit + 128));
 		}
 	class_destroy(pt_class);
-	unregister_chrdev(major, name);
+	unregister_chrdev(major);
 	for (unit = 0; unit < PT_UNITS; unit++)
 		if (pt[unit].present)
 			pi_release(pt[unit].pi);
--- a/drivers/char/drm/drm_drv.c
+++ b/drivers/char/drm/drm_drv.c
@@ -395,7 +395,7 @@ static int __init drm_core_init(void)
       err_p3:
 	drm_sysfs_destroy(drm_class);
       err_p2:
-	unregister_chrdev(DRM_MAJOR, "drm");
+	unregister_chrdev(DRM_MAJOR);
 	drm_free(drm_heads, sizeof(*drm_heads) * drm_cards_limit, DRM_MEM_STUB);
       err_p1:
 	return ret;
@@ -406,7 +406,7 @@ static void __exit drm_core_exit(void)
 	remove_proc_entry("dri", NULL);
 	drm_sysfs_destroy(drm_class);
 
-	unregister_chrdev(DRM_MAJOR, "drm");
+	unregister_chrdev(DRM_MAJOR);
 
 	drm_free(drm_heads, sizeof(*drm_heads) * drm_cards_limit, DRM_MEM_STUB);
 }
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -521,7 +521,7 @@ static int __init dsp56k_init_driver(voi
 	goto out;
 
 out_chrdev:
-	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
+	unregister_chrdev(DSP56K_MAJOR);
 out:
 	return err;
 }
@@ -531,7 +531,7 @@ static void __exit dsp56k_cleanup_driver
 {
 	class_device_destroy(dsp56k_class, MKDEV(DSP56K_MAJOR, 0));
 	class_destroy(dsp56k_class);
-	unregister_chrdev(DSP56K_MAJOR, "dsp56k");
+	unregister_chrdev(DSP56K_MAJOR);
 }
 module_exit(dsp56k_cleanup_driver);
 
--- a/drivers/char/dtlk.c
+++ b/drivers/char/dtlk.c
@@ -352,7 +352,7 @@ static void __exit dtlk_cleanup (void)
 						   signals... */
 
 	dtlk_write_tts(DTLK_CLEAR);
-	unregister_chrdev(dtlk_major, "dtlk");
+	unregister_chrdev(dtlk_major);
 	release_region(dtlk_port_lpc, DTLK_IO_EXTENT);
 }
 
--- a/drivers/char/ftape/zftape/zftape-init.c
+++ b/drivers/char/ftape/zftape/zftape-init.c
@@ -354,7 +354,7 @@ static void zft_exit(void)
 	int i;
 	TRACE_FUN(ft_t_flow);
 
-	if (unregister_chrdev(QIC117_TAPE_MAJOR, "zft") != 0) {
+	if (unregister_chrdev(QIC117_TAPE_MAJOR) != 0) {
 		TRACE(ft_t_warn, "failed");
 	} else {
 		TRACE(ft_t_info, "successful");
--- a/drivers/char/ip2/ip2main.c
+++ b/drivers/char/ip2/ip2main.c
@@ -425,7 +425,7 @@ #endif
 		printk(KERN_ERR "IP2: failed to unregister tty driver (%d)\n", err);
 	}
 	put_tty_driver(ip2_tty_driver);
-	if ( ( err = unregister_chrdev ( IP2_IPL_MAJOR, pcIpl ) ) ) {
+	if ( ( err = unregister_chrdev ( IP2_IPL_MAJOR ) ) ) {
 		printk(KERN_ERR "IP2: failed to unregister IPL driver (%d)\n", err);
 	}
 	remove_proc_entry("ip2mem", &proc_root);
@@ -778,7 +778,7 @@ retry:
 out_class:
 	class_destroy(ip2_class);
 out_chrdev:
-	unregister_chrdev(IP2_IPL_MAJOR, "ip2");
+	unregister_chrdev(IP2_IPL_MAJOR);
 out:
 	return err;
 }
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -868,7 +868,7 @@ static __init int init_ipmi_devintf(void
 
 	rv = ipmi_smi_watcher_register(&smi_watcher);
 	if (rv) {
-		unregister_chrdev(ipmi_major, DEVICE_NAME);
+		unregister_chrdev(ipmi_major);
 		class_destroy(ipmi_class);
 		printk(KERN_WARNING "ipmi: can't register smi watcher\n");
 		return rv;
@@ -890,7 +890,7 @@ static __exit void cleanup_ipmi(void)
 	mutex_unlock(&reg_list_mutex);
 	class_destroy(ipmi_class);
 	ipmi_smi_watcher_unregister(&smi_watcher);
-	unregister_chrdev(ipmi_major, DEVICE_NAME);
+	unregister_chrdev(ipmi_major);
 }
 module_exit(cleanup_ipmi);
 
--- a/drivers/char/istallion.c
+++ b/drivers/char/istallion.c
@@ -816,7 +816,7 @@ static void __exit istallion_module_exit
 	for (i = 0; i < 4; i++)
 		class_device_destroy(istallion_class, MKDEV(STL_SIOMEMMAJOR, i));
 	class_destroy(istallion_class);
-	if ((i = unregister_chrdev(STL_SIOMEMMAJOR, "staliomem")))
+	if ((i = unregister_chrdev(STL_SIOMEMMAJOR)))
 		printk("STALLION: failed to un-register serial memory device, "
 			"errno=%d\n", -i);
 
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -928,7 +928,7 @@ #endif
 out_class:
 	class_destroy(lp_class);
 out_devfs:
-	unregister_chrdev(LP_MAJOR, "lp");
+	unregister_chrdev(LP_MAJOR);
 	return err;
 }
 
@@ -970,7 +970,7 @@ #ifdef CONFIG_LP_CONSOLE
 	unregister_console (&lpcons);
 #endif
 
-	unregister_chrdev(LP_MAJOR, "lp");
+	unregister_chrdev(LP_MAJOR);
 	for (offset = 0; offset < LP_NO; offset++) {
 		if (lp_table[offset].dev == NULL)
 			continue;
--- a/drivers/char/mbcs.c
+++ b/drivers/char/mbcs.c
@@ -818,7 +818,7 @@ static void __exit mbcs_exit(void)
 {
 	int rv;
 
-	rv = unregister_chrdev(mbcs_major, DEVICE_NAME);
+	rv = unregister_chrdev(mbcs_major);
 	if (rv < 0)
 		DBG(KERN_ALERT "Error in unregister_chrdev: %d\n", rv);
 
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -1985,7 +1985,7 @@ static int __init cmm_init(void)
 
 	rc = pcmcia_register_driver(&cm4000_driver);
 	if (rc < 0) {
-		unregister_chrdev(major, DEVICE_NAME);
+		unregister_chrdev(major);
 		return rc;
 	}
 
@@ -1996,7 +1996,7 @@ static void __exit cmm_exit(void)
 {
 	printk(KERN_INFO MODULE_NAME ": unloading\n");
 	pcmcia_unregister_driver(&cm4000_driver);
-	unregister_chrdev(major, DEVICE_NAME);
+	unregister_chrdev(major);
 	class_destroy(cmm_class);
 };
 
--- a/drivers/char/pcmcia/cm4040_cs.c
+++ b/drivers/char/pcmcia/cm4040_cs.c
@@ -733,7 +733,7 @@ static int __init cm4040_init(void)
 
 	rc = pcmcia_register_driver(&reader_driver);
 	if (rc < 0) {
-		unregister_chrdev(major, DEVICE_NAME);
+		unregister_chrdev(major);
 		return rc;
 	}
 
@@ -744,7 +744,7 @@ static void __exit cm4040_exit(void)
 {
 	printk(KERN_INFO MODULE_NAME ": unloading\n");
 	pcmcia_unregister_driver(&reader_driver);
-	unregister_chrdev(major, DEVICE_NAME);
+	unregister_chrdev(major);
 	class_destroy(cmx_class);
 }
 
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -792,7 +792,7 @@ static int __init ppdev_init (void)
 out_class:
 	class_destroy(ppdev_class);
 out_chrdev:
-	unregister_chrdev(PP_MAJOR, CHRDEV);
+	unregister_chrdev(PP_MAJOR);
 out:
 	return err;
 }
@@ -802,7 +802,7 @@ static void __exit ppdev_cleanup (void)
 	/* Clean up all parport stuff */
 	parport_unregister_driver(&pp_driver);
 	class_destroy(ppdev_class);
-	unregister_chrdev (PP_MAJOR, CHRDEV);
+	unregister_chrdev (PP_MAJOR);
 }
 
 module_init(ppdev_init);
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -757,7 +757,7 @@ #endif
 	}
 	for (i = 0; i < 4; i++)
 		class_device_destroy(stallion_class, MKDEV(STL_SIOMEMMAJOR, i));
-	if ((i = unregister_chrdev(STL_SIOMEMMAJOR, "staliomem")))
+	if ((i = unregister_chrdev(STL_SIOMEMMAJOR)))
 		printk("STALLION: failed to un-register serial memory device, "
 			"errno=%d\n", -i);
 	class_destroy(stallion_class);
--- a/drivers/char/tipar.c
+++ b/drivers/char/tipar.c
@@ -513,7 +513,7 @@ out_class:
 	class_destroy(tipar_class);
 
 out_chrdev:
-	unregister_chrdev(TIPAR_MAJOR, "tipar");
+	unregister_chrdev(TIPAR_MAJOR);
 out:
 	return err;	
 }
@@ -526,7 +526,7 @@ tipar_cleanup_module(void)
 	/* Unregistering module */
 	parport_unregister_driver(&tipar_driver);
 
-	unregister_chrdev(TIPAR_MAJOR, "tipar");
+	unregister_chrdev(TIPAR_MAJOR);
 
 	for (i = 0; i < PP_NO; i++) {
 		if (table[i].dev == NULL)
--- a/drivers/char/tlclk.c
+++ b/drivers/char/tlclk.c
@@ -823,7 +823,7 @@ out3:
 out2:
 	kfree(alarm_events);
 out1:
-	unregister_chrdev(tlclk_major, "telco_clock");
+	unregister_chrdev(tlclk_major);
 	return ret;
 }
 
@@ -832,7 +832,7 @@ static void __exit tlclk_cleanup(void)
 	sysfs_remove_group(&tlclk_device->dev.kobj, &tlclk_attribute_group);
 	platform_device_unregister(tlclk_device);
 	misc_deregister(&tlclk_miscdev);
-	unregister_chrdev(tlclk_major, "telco_clock");
+	unregister_chrdev(tlclk_major);
 
 	release_region(TLCLK_BASE, 8);
 	del_timer_sync(&switchover_timer);
--- a/drivers/char/viotape.c
+++ b/drivers/char/viotape.c
@@ -1063,7 +1063,7 @@ int __init viotap_init(void)
 unreg_class:
 	class_destroy(tape_class);
 unreg_chrdev:
-	unregister_chrdev(VIOTAPE_MAJOR, "viotape");
+	unregister_chrdev(VIOTAPE_MAJOR);
 clear_handler:
 	vio_clearHandler(viomajorsubtype_tape);
 	viopath_close(viopath_hostLp, viomajorsubtype_tape, VIOTAPE_MAXREQ + 2);
@@ -1102,7 +1102,7 @@ static void __exit viotap_exit(void)
 	remove_proc_entry("iSeries/viotape", NULL);
 	vio_unregister_driver(&viotape_driver);
 	class_destroy(tape_class);
-	ret = unregister_chrdev(VIOTAPE_MAJOR, "viotape");
+	ret = unregister_chrdev(VIOTAPE_MAJOR);
 	if (ret < 0)
 		printk(VIOTAPE_KERN_WARN "Error unregistering device: %d\n",
 				ret);
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -500,7 +500,7 @@ static int __init i2c_dev_init(void)
 out_unreg_class:
 	class_destroy(i2c_dev_class);
 out_unreg_chrdev:
-	unregister_chrdev(I2C_MAJOR, "i2c");
+	unregister_chrdev(I2C_MAJOR);
 out:
 	printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
 	return res;
@@ -510,7 +510,7 @@ static void __exit i2c_dev_exit(void)
 {
 	i2c_del_driver(&i2cdev_driver);
 	class_destroy(i2c_dev_class);
-	unregister_chrdev(I2C_MAJOR,"i2c");
+	unregister_chrdev(I2C_MAJOR);
 }
 
 MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -4915,7 +4915,7 @@ static void __exit idetape_exit (void)
 {
 	driver_unregister(&idetape_driver.gen_driver);
 	class_destroy(idetape_sysfs_class);
-	unregister_chrdev(IDETAPE_MAJOR, "ht");
+	unregister_chrdev(IDETAPE_MAJOR);
 }
 
 static int __init idetape_init(void)
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1152,7 +1152,7 @@ static int __init input_init(void)
 static void __exit input_exit(void)
 {
 	input_proc_exit();
-	unregister_chrdev(INPUT_MAJOR, "input");
+	unregister_chrdev(INPUT_MAJOR);
 	class_unregister(&input_class);
 }
 
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -1508,7 +1508,7 @@ static int __init capi_init(void)
 	}
 	capi_class = class_create(THIS_MODULE, "capi");
 	if (IS_ERR(capi_class)) {
-		unregister_chrdev(capi_major, "capi20");
+		unregister_chrdev(capi_major);
 		return PTR_ERR(capi_class);
 	}
 
@@ -1518,7 +1518,7 @@ #ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
 	if (capinc_tty_init() < 0) {
 		class_device_destroy(capi_class, MKDEV(capi_major, 0));
 		class_destroy(capi_class);
-		unregister_chrdev(capi_major, "capi20");
+		unregister_chrdev(capi_major);
 		return -ENOMEM;
 	}
 #endif /* CONFIG_ISDN_CAPI_MIDDLEWARE */
@@ -1546,7 +1546,7 @@ static void __exit capi_exit(void)
 
 	class_device_destroy(capi_class, MKDEV(capi_major, 0));
 	class_destroy(capi_class);
-	unregister_chrdev(capi_major, "capi20");
+	unregister_chrdev(capi_major);
 
 #ifdef CONFIG_ISDN_CAPI_MIDDLEWARE
 	capinc_tty_exit();
--- a/drivers/isdn/hardware/eicon/divamnt.c
+++ b/drivers/isdn/hardware/eicon/divamnt.c
@@ -176,7 +176,7 @@ static struct file_operations divas_main
 
 static void divas_maint_unregister_chrdev(void)
 {
-	unregister_chrdev(major, DEVNAME);
+	unregister_chrdev(major);
 }
 
 static int DIVA_INIT_FUNCTION divas_maint_register_chrdev(void)
--- a/drivers/isdn/hardware/eicon/divasi.c
+++ b/drivers/isdn/hardware/eicon/divasi.c
@@ -143,7 +143,7 @@ static struct file_operations divas_idi_
 
 static void divas_idi_unregister_chrdev(void)
 {
-	unregister_chrdev(major, DEVNAME);
+	unregister_chrdev(major);
 }
 
 static int DIVA_INIT_FUNCTION divas_idi_register_chrdev(void)
--- a/drivers/isdn/hardware/eicon/divasmain.c
+++ b/drivers/isdn/hardware/eicon/divasmain.c
@@ -676,7 +676,7 @@ static struct file_operations divas_fops
 
 static void divas_unregister_chrdev(void)
 {
-	unregister_chrdev(major, DEVNAME);
+	unregister_chrdev(major);
 }
 
 static int DIVA_INIT_FUNCTION divas_register_chrdev(void)
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -2321,14 +2321,14 @@ #endif
 	if ((isdn_tty_modem_init()) < 0) {
 		printk(KERN_WARNING "isdn: Could not register tty devices\n");
 		vfree(dev);
-		unregister_chrdev(ISDN_MAJOR, "isdn");
+		unregister_chrdev(ISDN_MAJOR);
 		return -EIO;
 	}
 #ifdef CONFIG_ISDN_PPP
 	if (isdn_ppp_init() < 0) {
 		printk(KERN_WARNING "isdn: Could not create PPP-device-structs\n");
 		isdn_tty_exit();
-		unregister_chrdev(ISDN_MAJOR, "isdn");
+		unregister_chrdev(ISDN_MAJOR);
 		vfree(dev);
 		return -EIO;
 	}
@@ -2369,7 +2369,7 @@ #endif
 		return;
 	}
 	isdn_tty_exit();
-	unregister_chrdev(ISDN_MAJOR, "isdn");
+	unregister_chrdev(ISDN_MAJOR);
 	del_timer(&dev->timer);
 	/* call vfree with interrupts enabled, else it will hang */
 	vfree(dev);
--- a/drivers/media/video/videodev.c
+++ b/drivers/media/video/videodev.c
@@ -1651,7 +1651,7 @@ static int __init videodev_init(void)
 
 	ret = class_register(&video_class);
 	if (ret < 0) {
-		unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
+		unregister_chrdev(VIDEO_MAJOR);
 		printk(KERN_WARNING "video_dev: class_register failed\n");
 		return -EIO;
 	}
@@ -1662,7 +1662,7 @@ static int __init videodev_init(void)
 static void __exit videodev_exit(void)
 {
 	class_unregister(&video_class);
-	unregister_chrdev(VIDEO_MAJOR, VIDEO_NAME);
+	unregister_chrdev(VIDEO_MAJOR);
 }
 
 module_init(videodev_init)
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -785,7 +785,7 @@ static int __init init_mtdchar(void)
 
 	if (IS_ERR(mtd_class)) {
 		printk(KERN_ERR "Error creating mtd class.\n");
-		unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
+		unregister_chrdev(MTD_CHAR_MAJOR);
 		return PTR_ERR(mtd_class);
 	}
 
@@ -797,7 +797,7 @@ static void __exit cleanup_mtdchar(void)
 {
 	unregister_mtd_user(&notifier);
 	class_destroy(mtd_class);
-	unregister_chrdev(MTD_CHAR_MAJOR, "mtd");
+	unregister_chrdev(MTD_CHAR_MAJOR);
 }
 
 module_init(init_mtdchar);
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -869,7 +869,7 @@ out:
 	return err;
 
 out_chrdev:
-	unregister_chrdev(PPP_MAJOR, "ppp");
+	unregister_chrdev(PPP_MAJOR);
 	goto out;
 }
 
@@ -2670,7 +2670,7 @@ static void __exit ppp_cleanup(void)
 	if (atomic_read(&ppp_unit_count) || atomic_read(&channel_count))
 		printk(KERN_ERR "PPP: removing module but units remain!\n");
 	cardmap_destroy(&all_ppp_units);
-	if (unregister_chrdev(PPP_MAJOR, "ppp") != 0)
+	if (unregister_chrdev(PPP_MAJOR) != 0)
 		printk(KERN_ERR "PPP: failed to unregister PPP device\n");
 	class_device_destroy(ppp_class, MKDEV(PPP_MAJOR, 0));
 	class_destroy(ppp_class);
--- a/drivers/net/wan/cosa.c
+++ b/drivers/net/wan/cosa.c
@@ -387,7 +387,7 @@ #endif
 		cosa_probe(io[i], irq[i], dma[i]);
 	if (!nr_cards) {
 		printk(KERN_WARNING "cosa: no devices found.\n");
-		unregister_chrdev(cosa_major, "cosa");
+		unregister_chrdev(cosa_major);
 		err = -ENODEV;
 		goto out;
 	}
@@ -404,7 +404,7 @@ #endif
 	goto out;
 	
 out_chrdev:
-	unregister_chrdev(cosa_major, "cosa");
+	unregister_chrdev(cosa_major);
 out:
 	return err;
 }
@@ -432,7 +432,7 @@ static void __exit cosa_exit(void)
 		free_dma(cosa->dma);
 		release_region(cosa->datareg,is_8bit(cosa)?2:4);
 	}
-	unregister_chrdev(cosa_major, "cosa");
+	unregister_chrdev(cosa_major);
 }
 module_exit(cosa_exit);
 
--- a/drivers/pcmcia/pcmcia_ioctl.c
+++ b/drivers/pcmcia/pcmcia_ioctl.c
@@ -793,5 +793,5 @@ #ifdef CONFIG_PROC_FS
 	}
 #endif
 	if (major_dev != -1)
-		unregister_chrdev(major_dev, "pcmcia");
+		unregister_chrdev(major_dev);
 }
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -519,7 +519,7 @@ fs3270_init(void)
 static void __exit
 fs3270_exit(void)
 {
-	unregister_chrdev(IBM_FS3270_MAJOR, "fs3270");
+	unregister_chrdev(IBM_FS3270_MAJOR);
 }
 
 MODULE_LICENSE("GPL");
--- a/drivers/sbus/char/bpp.c
+++ b/drivers/sbus/char/bpp.c
@@ -1038,7 +1038,7 @@ static void __exit bpp_cleanup(void)
 {
 	unsigned idx;
 
-	unregister_chrdev(BPP_MAJOR, dev_name);
+	unregister_chrdev(BPP_MAJOR);
 
 	for (idx = 0;  idx < BPP_NO; idx++) {
 		if (instances[idx].present)
--- a/drivers/sbus/char/vfc_dev.c
+++ b/drivers/sbus/char/vfc_dev.c
@@ -720,7 +720,7 @@ void cleanup_module(void)
 {
 	struct vfc_dev **devp;
 
-	unregister_chrdev(VFC_MAJOR,vfcstr);
+	unregister_chrdev(VFC_MAJOR);
 
 	for (devp = vfc_dev_lst; *devp; devp++)
 		deinit_vfc_device(*devp);
--- a/drivers/scsi/3w-9xxx.c
+++ b/drivers/scsi/3w-9xxx.c
@@ -2166,7 +2166,7 @@ static void twa_remove(struct pci_dev *p
 
 	/* Unregister character device */
 	if (twa_major >= 0) {
-		unregister_chrdev(twa_major, "twa");
+		unregister_chrdev(twa_major);
 		twa_major = -1;
 	}
 
--- a/drivers/scsi/3w-xxxx.c
+++ b/drivers/scsi/3w-xxxx.c
@@ -2441,7 +2441,7 @@ static void tw_remove(struct pci_dev *pd
 
 	/* Unregister character device */
 	if (twe_major >= 0) {
-		unregister_chrdev(twe_major, "twe");
+		unregister_chrdev(twe_major);
 		twe_major = -1;
 	}
 
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -1046,7 +1046,7 @@ static int __init aac_init(void)
 static void __exit aac_exit(void)
 {
 	if (aac_cfg_major > -1)
-		unregister_chrdev(aac_cfg_major, "aac");
+		unregister_chrdev(aac_cfg_major);
 	pci_unregister_driver(&aac_pci_driver);
 }
 
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -994,7 +994,7 @@ static int __init init_ch_module(void)
 	return 0;
 
  fail2:
-	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
+	unregister_chrdev(SCSI_CHANGER_MAJOR);
  fail1:
 	class_destroy(ch_sysfs_class);
 	return rc;
@@ -1003,7 +1003,7 @@ static int __init init_ch_module(void)
 static void __exit exit_ch_module(void) 
 {
 	scsi_unregister_driver(&ch_template.gendrv);
-	unregister_chrdev(SCSI_CHANGER_MAJOR, "ch");
+	unregister_chrdev(SCSI_CHANGER_MAJOR);
 	class_destroy(ch_sysfs_class);
 }
 
--- a/drivers/scsi/dpt_i2o.c
+++ b/drivers/scsi/dpt_i2o.c
@@ -1079,7 +1079,7 @@ static void adpt_i2o_delete_hba(adpt_hba
 	kfree(pHba);
 
 	if(hba_count <= 0){
-		unregister_chrdev(DPTI_I2O_MAJOR, DPT_DRIVER);   
+		unregister_chrdev(DPTI_I2O_MAJOR);   
 	}
 }
 
--- a/drivers/scsi/gdth.c
+++ b/drivers/scsi/gdth.c
@@ -4779,7 +4779,7 @@ #endif
 #ifdef GDTH_STATISTICS
             del_timer(&gdth_timer);
 #endif
-            unregister_chrdev(major,"gdth");
+            unregister_chrdev(major);
             unregister_reboot_notifier(&gdth_notifier);
         }
     }
--- a/drivers/scsi/hptiop.c
+++ b/drivers/scsi/hptiop.c
@@ -1482,7 +1482,7 @@ static int __init hptiop_module_init(voi
 static void __exit hptiop_module_exit(void)
 {
 	dprintk("hptiop_module_exit\n");
-	unregister_chrdev(hptiop_cdev_major, "hptiop");
+	unregister_chrdev(hptiop_cdev_major);
 	pci_unregister_driver(&hptiop_pci_driver);
 }
 
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -5100,7 +5100,7 @@ static void __exit megaraid_exit(void)
 	/*
 	 * Unregister the character device interface to the driver.
 	 */
-	unregister_chrdev(major, "megadev_legacy");
+	unregister_chrdev(major);
 
 	pci_unregister_driver(&megaraid_pci_driver);
 
--- a/drivers/scsi/megaraid/megaraid_mm.c
+++ b/drivers/scsi/megaraid/megaraid_mm.c
@@ -1238,7 +1238,7 @@ mraid_mm_exit(void)
 {
 	con_log(CL_DLEVEL1 , ("exiting common mod\n"));
 
-	unregister_chrdev(majorno, "megadev");
+	unregister_chrdev(majorno);
 }
 
 module_init(mraid_mm_init);
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -2858,7 +2858,7 @@ static int __init megasas_init(void)
 
 	if (rval) {
 		printk(KERN_DEBUG "megasas: PCI hotplug regisration failed \n");
-		unregister_chrdev(megasas_mgmt_majorno, "megaraid_sas_ioctl");
+		unregister_chrdev(megasas_mgmt_majorno);
 	}
 
 	driver_create_file(&megasas_pci_driver.driver, &driver_attr_version);
@@ -2878,7 +2878,7 @@ static void __exit megasas_exit(void)
 			   &driver_attr_release_date);
 
 	pci_unregister_driver(&megasas_pci_driver);
-	unregister_chrdev(megasas_mgmt_majorno, "megaraid_sas_ioctl");
+	unregister_chrdev(megasas_mgmt_majorno);
 }
 
 module_init(megasas_init);
--- a/drivers/scsi/osst.c
+++ b/drivers/scsi/osst.c
@@ -5925,7 +5925,7 @@ static void __exit exit_osst (void)
 
 	osst_remove_driverfs_files(&osst_template.gendrv);
 	scsi_unregister_driver(&osst_template.gendrv);
-	unregister_chrdev(OSST_MAJOR, "osst");
+	unregister_chrdev(OSST_MAJOR);
 	osst_sysfs_cleanup();
 
 	if (os_scsi_tapes) {
--- a/drivers/telephony/phonedev.c
+++ b/drivers/telephony/phonedev.c
@@ -155,7 +155,7 @@ static int __init telephony_init(void)
 
 static void __exit telephony_exit(void)
 {
-	unregister_chrdev(PHONE_MAJOR, "telephony");
+	unregister_chrdev(PHONE_MAJOR);
 }
 
 module_init(telephony_init);
--- a/drivers/usb/core/file.c
+++ b/drivers/usb/core/file.c
@@ -120,7 +120,7 @@ int usb_major_init(void)
 
 void usb_major_cleanup(void)
 {
-	unregister_chrdev(USB_MAJOR, "usb");
+	unregister_chrdev(USB_MAJOR);
 }
 
 /**
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1416,7 +1416,7 @@ static void __exit
 fbmem_exit(void)
 {
 	class_destroy(fb_class);
-	unregister_chrdev(FB_MAJOR, "fb");
+	unregister_chrdev(FB_MAJOR);
 }
 
 module_exit(fbmem_exit);
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -253,7 +253,7 @@ void unregister_chrdev_region(dev_t from
 	}
 }
 
-int unregister_chrdev(unsigned int major, const char *name)
+int unregister_chrdev(unsigned int major)
 {
 	struct char_device_struct *cd;
 	cd = __unregister_chrdev_region(major, 0, 256);
--- a/fs/coda/psdev.c
+++ b/fs/coda/psdev.c
@@ -371,7 +371,7 @@ static int init_coda_psdev(void)
 	goto out;
 
 out_chrdev:
-	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
+	unregister_chrdev(CODA_PSDEV_MAJOR);
 out:
 	return err;
 }
@@ -411,7 +411,7 @@ out:
 	for (i = 0; i < MAX_CODADEVS; i++)
 		class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 	class_destroy(coda_psdev_class);
-	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
+	unregister_chrdev(CODA_PSDEV_MAJOR);
 	coda_sysctl_clean();
 out1:
 	coda_destroy_inodecache();
@@ -430,7 +430,7 @@ static void __exit exit_coda(void)
 	for (i = 0; i < MAX_CODADEVS; i++)
 		class_device_destroy(coda_psdev_class, MKDEV(CODA_PSDEV_MAJOR, i));
 	class_destroy(coda_psdev_class);
-	unregister_chrdev(CODA_PSDEV_MAJOR, "coda");
+	unregister_chrdev(CODA_PSDEV_MAJOR);
 	coda_sysctl_clean();
 	coda_destroy_inodecache();
 }
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1473,7 +1473,7 @@ extern int alloc_chrdev_region(dev_t *, 
 extern int register_chrdev_region(dev_t, unsigned, const char *);
 extern int register_chrdev(unsigned int, const char *,
 			   const struct file_operations *);
-extern int unregister_chrdev(unsigned int, const char *);
+extern int unregister_chrdev(unsigned int);
 extern void unregister_chrdev_region(dev_t, unsigned);
 extern int chrdev_open(struct inode *, struct file *);
 extern void chrdev_show(struct seq_file *,off_t);
--- a/sound/core/sound.c
+++ b/sound/core/sound.c
@@ -406,7 +406,7 @@ static int __init alsa_sound_init(void)
 		return -EIO;
 	}
 	if (snd_info_init() < 0) {
-		unregister_chrdev(major, "alsa");
+		unregister_chrdev(major);
 		return -ENOMEM;
 	}
 	snd_info_minor_register();
@@ -420,7 +420,7 @@ static void __exit alsa_sound_exit(void)
 {
 	snd_info_minor_unregister();
 	snd_info_done();
-	if (unregister_chrdev(major, "alsa") != 0)
+	if (unregister_chrdev(major) != 0)
 		snd_printk(KERN_ERR "unable to unregister major device number %d\n", major);
 }
 
--- a/sound/sound_core.c
+++ b/sound/sound_core.c
@@ -564,7 +564,7 @@ static void __exit cleanup_soundcore(voi
 {
 	/* We have nothing to really do here - we know the lists must be
 	   empty */
-	unregister_chrdev(SOUND_MAJOR, "sound");
+	unregister_chrdev(SOUND_MAJOR);
 	class_destroy(sound_class);
 }
 

Re: [PATCH] Drop second arg of unregister_chrdev()

[Andrew Morton]

On Tue, 15 Aug 2006 07:35:22 +0400
Alexey Dobriyan <adobriyan@gmail.com> wrote:

> * "name" is trivially unused.

OK.

> * Requirement to pass to unregister function anything but cookie you've
>   got from register counterpart is wrong. It creates opportunity to
>   diverge, it create opportunity for bugs if enforced:
> 
> 	/*
> 	 * XXX(hch): bp->b_count_desired might be incorrect (see
> 	 * xfs_buf_associate_memory for details),
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> 
> 	 *                                        but fortunately
> 	 * the Linux version of kmem_free ignores the len argument..
> 	 */
> 	 kmem_free(bp->b_addr, bp->b_count_desired);

I don't understand that.

>  64 files changed, 97 insertions(+), 97 deletions(-)

I do understand that.  This'll cause some grief.  I'd suggest that we add a
new unregister_char_dev() or something, and do

static inline unregister_chrdev(unsigned int major, const char *name)
{
	return unregister_char_dev(major);
}

then migrate callers over to unregister_char_dev() in an organised fashion,
via maintainers where poss.

Then mark unregister_chrdev() deprecated for a while.

Then nuke it.

Re: [PATCH] Drop second arg of unregister_chrdev()

[Alexey Dobriyan]

On Mon, Aug 14, 2006 at 08:48:17PM -0700, Andrew Morton wrote:
> On Tue, 15 Aug 2006 07:35:22 +0400
> Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> > * "name" is trivially unused.
>
> OK.
>
> > * Requirement to pass to unregister function anything but cookie you've
> >   got from register counterpart is wrong. It creates opportunity to
> >   diverge, it create opportunity for bugs if enforced:
> >
> > 	/*
> > 	 * XXX(hch): bp->b_count_desired might be incorrect (see
> > 	 * xfs_buf_associate_memory for details),
> >
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> >
> > 	 *                                        but fortunately
> > 	 * the Linux version of kmem_free ignores the len argument..
> > 	 */
> > 	 kmem_free(bp->b_addr, bp->b_count_desired);
>
> I don't understand that.

	p = malloc(size);
	free(p);
is good. You don't have to remember "size" which sometimes nontrivially
calculated until free time.

	mmio = ioremap(start, size);
	iounmap(mmio);
is good too for same reasons. Agree so far?

Ergo,
	major = register_chrdev(0, "foo", &foo_fops);
	unregister_chrdev(major);
is good too even if people don't forget to pass the same "foo" in two
places. Luckily, unregister_chrdev() ignores name arg, so passing wrong
won't do any harm.

> >  64 files changed, 97 insertions(+), 97 deletions(-)
>
> I do understand that.  This'll cause some grief.

In kernel, hardly...

$ grep unregister_chrdev -w -n 2.6.18-rc4-mm1
33126:  unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
35853:  unregister_chrdev(MSR_MAJOR, "cpu/msr");
35861:  unregister_chrdev(MSR_MAJOR, "cpu/msr");
134610:         unregister_chrdev(LP_MAJOR, "lp");
291207:-        unregister_chrdev(hptiop_cdev_major, "hptiop");
352167:+    unregister_chrdev(major_number, "SerialQT_USB");

Two rejects, 4 fuzzy places.

> I'd suggest that we add a
> new unregister_char_dev() or something, and do

But there is register_CHRDEV_region, unregister_CHRDEV_region,
alloc_CHRDEV_region, register_CHRDEV. Should I change the spelling of
register_chrdev() for a good measure, too?

> static inline unregister_chrdev(unsigned int major, const char *name)
> {
> 	return unregister_char_dev(major);
> }

> then migrate callers over to unregister_char_dev() in an organised fashion,
> via maintainers where poss.
>
> Then mark unregister_chrdev() deprecated for a while.
>
> Then nuke it.

Re: [PATCH] Drop second arg of unregister_chrdev()

[Jonathan Corbet]

> * "name" is trivially unused.
> * Requirement to pass to unregister function anything but cookie you've
>   got from register counterpart is wrong.

Might this, instead, be an opportunity to get rid of the internal
register_chrdev() and unregister_chrdev() calls in favor of the cdev
interface?  register_chrdev() is a bit of a backward-compatibility hack
at this point, and cdevs, in theory, are safer since they won't present
drivers with minor numbers they might not be prepared to handle.

jon

Re: [PATCH] Drop second arg of unregister_chrdev()

[Rolf Eike Beer]

[-- Attachment #1: Type: text/plain, Size: 691 bytes --]

Jonathan Corbet wrote:
> > * "name" is trivially unused.
> > * Requirement to pass to unregister function anything but cookie you've
> >   got from register counterpart is wrong.
>
> Might this, instead, be an opportunity to get rid of the internal
> register_chrdev() and unregister_chrdev() calls in favor of the cdev
> interface?  register_chrdev() is a bit of a backward-compatibility hack
> at this point, and cdevs, in theory, are safer since they won't present
> drivers with minor numbers they might not be prepared to handle.

In this case I would suggest to add documentation to this functions first to 
get people the chance to actually know how to use them.

Eike

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Re: [PATCH] Drop second arg of unregister_chrdev()

[Jonathan Corbet]

Rolf Eike Beer <eike-kernel@sf-tec.de> wrote:

> > Might this, instead, be an opportunity to get rid of the internal
> > register_chrdev() and unregister_chrdev() calls in favor of the cdev
> > interface?
> 
> In this case I would suggest to add documentation to this functions first to 
> get people the chance to actually know how to use them.

Good point.  My article (http://lwn.net/Articles/49684/) has been
somewhat overtaken by time, though I do think that the discussion in
LDD3 is still applicable.  I'll see what I can do about that side of
things.

jon

cdev documentation (was Drop second arg of unregister_chrdev())

[Jonathan Corbet]

Rolf Eike Beer <eike-kernel@sf-tec.de> wrote:

> > Might this, instead, be an opportunity to get rid of the internal
> > register_chrdev() and unregister_chrdev() calls in favor of the cdev
> > interface?
> 
> In this case I would suggest to add documentation to this functions first to 
> get people the chance to actually know how to use them.

How's the following?  Quickly done but, I hope, useful.

I've also put something more tutorial-oriented at:

	http://lwn.net/SubscriberLink/195805/b835f36d3b8ee266/

This can be formatted up for the Documentation directory if so desired.

jon

---

Add some documentation comments for the cdev interface.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff -rpuN -X current/Documentation/dontdiff 2.6.18-rc4/Documentation/DocBook/kernel-api.tmpl 2.6.18-rc4-jc1/Documentation/DocBook/kernel-api.tmpl
--- 2.6.18-rc4/Documentation/DocBook/kernel-api.tmpl	2006-08-16 15:21:11.000000000 -0600
+++ 2.6.18-rc4-jc1/Documentation/DocBook/kernel-api.tmpl	2006-08-17 14:25:47.000000000 -0600
@@ -437,6 +437,11 @@ X!Edrivers/pnp/system.c
 !Eblock/ll_rw_blk.c
   </chapter>
 
+  <chapter id="chrdev">
+	<title>Char devices</title>
+!Efs/char_dev.c
+  </chapter>
+
   <chapter id="miscdev">
      <title>Miscellaneous Devices</title>
 !Edrivers/char/misc.c
diff -rpuN -X current/Documentation/dontdiff 2.6.18-rc4/fs/char_dev.c 2.6.18-rc4-jc1/fs/char_dev.c
--- 2.6.18-rc4/fs/char_dev.c	2006-08-16 15:21:44.000000000 -0600
+++ 2.6.18-rc4-jc1/fs/char_dev.c	2006-08-17 14:22:16.000000000 -0600
@@ -146,6 +146,15 @@ __unregister_chrdev_region(unsigned majo
 	return cd;
 }
 
+/**
+ * register_chrdev_region() - register a range of device numbers
+ * @from: the first in the desired range of device numbers; must include
+ *        the major number.
+ * @count: the number of consecutive device numbers required
+ * @name: the name of the device or driver.
+ *
+ * Return value is zero on success, a negative error code on failure.
+ */
 int register_chrdev_region(dev_t from, unsigned count, const char *name)
 {
 	struct char_device_struct *cd;
@@ -171,6 +180,17 @@ fail:
 	return PTR_ERR(cd);
 }
 
+/**
+ * alloc_chrdev_region() - register a range of char device numbers
+ * @dev: output parameter for first assigned number
+ * @baseminor: first of the requested range of minor numbers
+ * @count: the number of minor numbers required
+ * @name: the name of the associated device or driver
+ *
+ * Allocates a range of char device numbers.  The major number will be
+ * chosen dynamically, and returned (along with the first minor number)
+ * in @dev.  Returns zero or a negative error code.
+ */
 int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count,
 			const char *name)
 {
@@ -240,6 +260,15 @@ out2:
 	return err;
 }
 
+/**
+ * unregister_chrdev_region() - return a range of device numbers
+ * @from: the first in the range of numbers to unregister
+ * @count: the number of device numbers to unregister
+ *
+ * This function will unregister a range of @count device numbers,
+ * starting with @from.  The caller should normally be the one who
+ * allocated those numbers in the first place...
+ */
 void unregister_chrdev_region(dev_t from, unsigned count)
 {
 	dev_t to = from + count;
@@ -377,6 +406,16 @@ static int exact_lock(dev_t dev, void *d
 	return cdev_get(p) ? 0 : -1;
 }
 
+/**
+ * cdev_add() - add a char device to the system
+ * @p: the cdev structure for the device
+ * @dev: the first device number for which this device is responsible
+ * @count: the number of consecutive minor numbers corresponding to this
+ *         device
+ *
+ * cdev_add() adds the device represented by @p to the system, making it
+ * live immediately.  A negative error code is returned on failure.
+ */
 int cdev_add(struct cdev *p, dev_t dev, unsigned count)
 {
 	p->dev = dev;
@@ -389,6 +428,13 @@ static void cdev_unmap(dev_t dev, unsign
 	kobj_unmap(cdev_map, dev, count);
 }
 
+/**
+ * cdev_del() - remove a cdev from the system
+ * @p: the cdev structure to be removed
+ *
+ * cdev_del() removes @p from the system, possibly freeing the structure
+ * itself.
+ */
 void cdev_del(struct cdev *p)
 {
 	cdev_unmap(p->dev, p->count);
@@ -417,6 +463,11 @@ static struct kobj_type ktype_cdev_dynam
 	.release	= cdev_dynamic_release,
 };
 
+/**
+ * cdev_alloc() - allocate a cdev structure
+ *
+ * Allocates and returns a cdev structure, or NULL on failure.
+ */
 struct cdev *cdev_alloc(void)
 {
 	struct cdev *p = kzalloc(sizeof(struct cdev), GFP_KERNEL);
@@ -428,6 +479,14 @@ struct cdev *cdev_alloc(void)
 	return p;
 }
 
+/**
+ * cdev_init() - initialize a cdev structure
+ * @cdev: the structure to initialize
+ * @fops: the file_operations for this device
+ *
+ * Initializes @cdev, remembering @fops, making it ready to add to the
+ * system with cdev_add().
+ */
 void cdev_init(struct cdev *cdev, const struct file_operations *fops)
 {
 	memset(cdev, 0, sizeof *cdev);

Re: cdev documentation (was Drop second arg of unregister_chrdev())

[Rolf Eike Beer]

[-- Attachment #1: Type: text/plain, Size: 1399 bytes --]

Jonathan Corbet wrote:
> Rolf Eike Beer <eike-kernel@sf-tec.de> wrote:
> > > Might this, instead, be an opportunity to get rid of the internal
> > > register_chrdev() and unregister_chrdev() calls in favor of the cdev
> > > interface?
> >
> > In this case I would suggest to add documentation to this functions first
> > to get people the chance to actually know how to use them.
>
> How's the following?  Quickly done but, I hope, useful.
>
> I've also put something more tutorial-oriented at:
>
> 	http://lwn.net/SubscriberLink/195805/b835f36d3b8ee266/
>
> This can be formatted up for the Documentation directory if so desired.

Thanks from the "other developer". What I would like to have is a function 
that gives me the next (or even a random) available number from my range. 
Currently I have to do it on my own AFAICS. 

Nevertheless, I ported my driver to the new interface. I see it cdev_add() 
succeeding, but the device never shows up in sysfs. Do I have to do any more 
tricks with class devices and stuff?

While I was sneaking around in the code I found this drivers/char/tty_io:3093

        cdev_init(&driver->cdev, &tty_fops);
        driver->cdev.owner = driver->owner;
        error = cdev_add(&driver->cdev, dev, driver->num);
        if (error) {
                cdev_del(&driver->cdev);

Isn't the call to cdev_del() just wrong here?

Eike

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Re: cdev documentation (was Drop second arg of unregister_chrdev())

[Dmitry Torokhov]

On 8/18/06, Rolf Eike Beer <eike-kernel@sf-tec.de> wrote:
>
> While I was sneaking around in the code I found this drivers/char/tty_io:3093
>
>        cdev_init(&driver->cdev, &tty_fops);
>        driver->cdev.owner = driver->owner;
>        error = cdev_add(&driver->cdev, dev, driver->num);
>        if (error) {
>                cdev_del(&driver->cdev);
>
> Isn't the call to cdev_del() just wrong here?
>

Yes, itlooks like it shouldjust be removed.

-- 
Dmitry

[TTY] Remove bogus call to cdev_del()

[Rolf Eike Beer]

When cdev_add() failed there is no reason to call cdev_del().

Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de>

---
commit d31aa8d2f27346fe0663bd9675185c649d5d9801
tree 67f30f1547f19eb2bc0961abf5b4e2f35834ed41
parent f6272846a16df0c7acb5c1701c0acdee0b472047
author Rolf Eike Beer <eike-kernel@sf-tec.de> Fri, 18 Aug 2006 14:45:01 +0200
committer Rolf Eike Beer <beer@siso-eb-i34d.silicon-software.de> Fri, 18 Aug 2006 14:45:01 +0200

 drivers/char/tty_io.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index bfdb902..d6e4eaa 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -3094,7 +3094,6 @@ int tty_register_driver(struct tty_drive
 	driver->cdev.owner = driver->owner;
 	error = cdev_add(&driver->cdev, dev, driver->num);
 	if (error) {
-		cdev_del(&driver->cdev);
 		unregister_chrdev_region(dev, driver->num);
 		driver->ttys = NULL;
 		driver->termios = driver->termios_locked = NULL;

Re: cdev documentation (was Drop second arg of unregister_chrdev())

[Jonathan Corbet]

Rolf Eike Beer <eike-kernel@sf-tec.de> wrote:

> Nevertheless, I ported my driver to the new interface. I see it cdev_add() 
> succeeding, but the device never shows up in sysfs. Do I have to do any more 
> tricks with class devices and stuff?

Yes, cdevs do not, themselves, show up in sysfs.  A simple class is what
you want for that part of the job.

> While I was sneaking around in the code I found this drivers/char/tty_io:3093
> 
>         cdev_init(&driver->cdev, &tty_fops);
>         driver->cdev.owner = driver->owner;
>         error = cdev_add(&driver->cdev, dev, driver->num);
>         if (error) {
>                 cdev_del(&driver->cdev);
> 
> Isn't the call to cdev_del() just wrong here?

It is correct, in that it returns the reference you hold to the cdev's
internal kobject.  If you got the cdev with cdev_alloc(), that's the
only way it will get returned to the system.  For a cdev allocated
elsewhere (as is the case here) it probably doesn't make any difference.

jon

Re: cdev documentation (was Drop second arg of unregister_chrdev())

[Dmitry Torokhov]

On 8/18/06, Jonathan Corbet <corbet@lwn.net> wrote:
> Rolf Eike Beer <eike-kernel@sf-tec.de> wrote:
>
> > Nevertheless, I ported my driver to the new interface. I see it cdev_add()
> > succeeding, but the device never shows up in sysfs. Do I have to do any more
> > tricks with class devices and stuff?
>
> Yes, cdevs do not, themselves, show up in sysfs.  A simple class is what
> you want for that part of the job.
>
> > While I was sneaking around in the code I found this drivers/char/tty_io:3093
> >
> >         cdev_init(&driver->cdev, &tty_fops);
> >         driver->cdev.owner = driver->owner;
> >         error = cdev_add(&driver->cdev, dev, driver->num);
> >         if (error) {
> >                 cdev_del(&driver->cdev);
> >
> > Isn't the call to cdev_del() just wrong here?
>
> It is correct, in that it returns the reference you hold to the cdev's
> internal kobject.  If you got the cdev with cdev_alloc(), that's the
> only way it will get returned to the system.  For a cdev allocated
> elsewhere (as is the case here) it probably doesn't make any difference.
>

This is not a good practice though because it will attempt to unmap
device that is not mapped. Depeneding on changes in kmap code (for
example adding checks for regions being busy) blindly calling unmap
could unmap some other cdev. For dynamically allocated objects calling
kobject_put(&cdev->kobj) would be more correct but not very nice.

-- 
Dmitry