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* [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
@ 2019-08-11 15:36 Max Staudt
  2019-08-11 15:40 ` Max Staudt
  2019-08-11 19:28 ` Max Staudt
  0 siblings, 2 replies; 9+ messages in thread
From: Max Staudt @ 2019-08-11 15:36 UTC (permalink / raw)
  To: b.zolnierkie, axboe
  Cc: linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert,
	Max Staudt

Up until now, the pata_buddha driver would only check for cards on
initcall time. Now, the kernel will call its probe function as soon
as a compatible card is detected.

v4: Cleap up pata_buddha_probe() by using ent->driver_data,
    Support X-Surf via late_initcall()

v3: Clean up devm_*, implement device removal.

v2: Rename 'zdev' to 'z' to make the patch easy to analyse with
    git diff --ignore-space-change

Tested-by: Max Staudt <max@enpas.org>
Signed-off-by: Max Staudt <max@enpas.org>
---
 drivers/ata/pata_buddha.c | 243 ++++++++++++++++++++++++++++------------------
 1 file changed, 150 insertions(+), 93 deletions(-)

diff --git a/drivers/ata/pata_buddha.c b/drivers/ata/pata_buddha.c
index 11a8044ff..25d03b595 100644
--- a/drivers/ata/pata_buddha.c
+++ b/drivers/ata/pata_buddha.c
@@ -18,7 +18,9 @@
 #include <linux/kernel.h>
 #include <linux/libata.h>
 #include <linux/mm.h>
+#include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/types.h>
 #include <linux/zorro.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_host.h>
@@ -29,7 +31,7 @@
 #include <asm/setup.h>
 
 #define DRV_NAME "pata_buddha"
-#define DRV_VERSION "0.1.0"
+#define DRV_VERSION "0.1.1"
 
 #define BUDDHA_BASE1	0x800
 #define BUDDHA_BASE2	0xa00
@@ -47,11 +49,11 @@ enum {
 	BOARD_XSURF
 };
 
-static unsigned int buddha_bases[3] __initdata = {
+static unsigned int buddha_bases[3] = {
 	BUDDHA_BASE1, BUDDHA_BASE2, BUDDHA_BASE3
 };
 
-static unsigned int xsurf_bases[2] __initdata = {
+static unsigned int xsurf_bases[2] = {
 	XSURF_BASE1, XSURF_BASE2
 };
 
@@ -145,111 +147,166 @@ static struct ata_port_operations pata_xsurf_ops = {
 	.set_mode	= pata_buddha_set_mode,
 };
 
-static int __init pata_buddha_init_one(void)
+static int pata_buddha_probe(struct zorro_dev *z,
+			     const struct zorro_device_id *ent)
 {
-	struct zorro_dev *z = NULL;
+	static const char * const board_name[]
+		= { "Buddha", "Catweasel", "X-Surf" };
+	struct ata_host *host;
+	void __iomem *buddha_board;
+	unsigned long board;
+	unsigned int type = ent->driver_data;
+	unsigned int nr_ports = (type == BOARD_CATWEASEL) ? 3 : 2;
+	int i;
+
+	dev_info(&z->dev, "%s IDE controller\n", board_name[type]);
+
+	board = z->resource.start;
+
+	if (type != BOARD_XSURF) {
+		if (!devm_request_mem_region(&z->dev,
+					     board + BUDDHA_BASE1,
+					     0x800, DRV_NAME))
+			return -ENXIO;
+	} else {
+		if (!devm_request_mem_region(&z->dev,
+					     board + XSURF_BASE1,
+					     0x1000, DRV_NAME))
+			return -ENXIO;
+		if (!devm_request_mem_region(&z->dev,
+					     board + XSURF_BASE2,
+					     0x1000, DRV_NAME)) {
+		}
+	}
+
+	/* allocate host */
+	host = ata_host_alloc(&z->dev, nr_ports);
+	if (!host)
+		return -ENXIO;
+
+	buddha_board = ZTWO_VADDR(board);
 
-	while ((z = zorro_find_device(ZORRO_WILDCARD, z))) {
-		static const char *board_name[]
-			= { "Buddha", "Catweasel", "X-Surf" };
-		struct ata_host *host;
-		void __iomem *buddha_board;
-		unsigned long board;
-		unsigned int type, nr_ports = 2;
-		int i;
-
-		if (z->id == ZORRO_PROD_INDIVIDUAL_COMPUTERS_BUDDHA) {
-			type = BOARD_BUDDHA;
-		} else if (z->id == ZORRO_PROD_INDIVIDUAL_COMPUTERS_CATWEASEL) {
-			type = BOARD_CATWEASEL;
-			nr_ports++;
-		} else if (z->id == ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF) {
-			type = BOARD_XSURF;
-		} else
-			continue;
-
-		dev_info(&z->dev, "%s IDE controller\n", board_name[type]);
-
-		board = z->resource.start;
+	/* enable the board IRQ on Buddha/Catweasel */
+	if (type != BOARD_XSURF)
+		z_writeb(0, buddha_board + BUDDHA_IRQ_MR);
+
+	for (i = 0; i < nr_ports; i++) {
+		struct ata_port *ap = host->ports[i];
+		void __iomem *base, *irqport;
+		unsigned long ctl = 0;
 
 		if (type != BOARD_XSURF) {
-			if (!devm_request_mem_region(&z->dev,
-						     board + BUDDHA_BASE1,
-						     0x800, DRV_NAME))
-				continue;
+			ap->ops = &pata_buddha_ops;
+			base = buddha_board + buddha_bases[i];
+			ctl = BUDDHA_CONTROL;
+			irqport = buddha_board + BUDDHA_IRQ + i * 0x40;
 		} else {
-			if (!devm_request_mem_region(&z->dev,
-						     board + XSURF_BASE1,
-						     0x1000, DRV_NAME))
-				continue;
-			if (!devm_request_mem_region(&z->dev,
-						     board + XSURF_BASE2,
-						     0x1000, DRV_NAME))
-				continue;
+			ap->ops = &pata_xsurf_ops;
+			base = buddha_board + xsurf_bases[i];
+			/* X-Surf has no CS1* (Control/AltStat) */
+			irqport = buddha_board + XSURF_IRQ;
 		}
 
-		/* allocate host */
-		host = ata_host_alloc(&z->dev, nr_ports);
-		if (!host)
-			continue;
-
-		buddha_board = ZTWO_VADDR(board);
-
-		/* enable the board IRQ on Buddha/Catweasel */
-		if (type != BOARD_XSURF)
-			z_writeb(0, buddha_board + BUDDHA_IRQ_MR);
-
-		for (i = 0; i < nr_ports; i++) {
-			struct ata_port *ap = host->ports[i];
-			void __iomem *base, *irqport;
-			unsigned long ctl = 0;
-
-			if (type != BOARD_XSURF) {
-				ap->ops = &pata_buddha_ops;
-				base = buddha_board + buddha_bases[i];
-				ctl = BUDDHA_CONTROL;
-				irqport = buddha_board + BUDDHA_IRQ + i * 0x40;
-			} else {
-				ap->ops = &pata_xsurf_ops;
-				base = buddha_board + xsurf_bases[i];
-				/* X-Surf has no CS1* (Control/AltStat) */
-				irqport = buddha_board + XSURF_IRQ;
-			}
-
-			ap->pio_mask = ATA_PIO4;
-			ap->flags |= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_IORDY;
-
-			ap->ioaddr.data_addr		= base;
-			ap->ioaddr.error_addr		= base + 2 + 1 * 4;
-			ap->ioaddr.feature_addr		= base + 2 + 1 * 4;
-			ap->ioaddr.nsect_addr		= base + 2 + 2 * 4;
-			ap->ioaddr.lbal_addr		= base + 2 + 3 * 4;
-			ap->ioaddr.lbam_addr		= base + 2 + 4 * 4;
-			ap->ioaddr.lbah_addr		= base + 2 + 5 * 4;
-			ap->ioaddr.device_addr		= base + 2 + 6 * 4;
-			ap->ioaddr.status_addr		= base + 2 + 7 * 4;
-			ap->ioaddr.command_addr		= base + 2 + 7 * 4;
-
-			if (ctl) {
-				ap->ioaddr.altstatus_addr = base + ctl;
-				ap->ioaddr.ctl_addr	  = base + ctl;
-			}
-
-			ap->private_data = (void *)irqport;
-
-			ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx", board,
-				      ctl ? board + buddha_bases[i] + ctl : 0);
+		ap->pio_mask = ATA_PIO4;
+		ap->flags |= ATA_FLAG_SLAVE_POSS | ATA_FLAG_NO_IORDY;
+
+		ap->ioaddr.data_addr		= base;
+		ap->ioaddr.error_addr		= base + 2 + 1 * 4;
+		ap->ioaddr.feature_addr		= base + 2 + 1 * 4;
+		ap->ioaddr.nsect_addr		= base + 2 + 2 * 4;
+		ap->ioaddr.lbal_addr		= base + 2 + 3 * 4;
+		ap->ioaddr.lbam_addr		= base + 2 + 4 * 4;
+		ap->ioaddr.lbah_addr		= base + 2 + 5 * 4;
+		ap->ioaddr.device_addr		= base + 2 + 6 * 4;
+		ap->ioaddr.status_addr		= base + 2 + 7 * 4;
+		ap->ioaddr.command_addr		= base + 2 + 7 * 4;
+
+		if (ctl) {
+			ap->ioaddr.altstatus_addr = base + ctl;
+			ap->ioaddr.ctl_addr	  = base + ctl;
 		}
 
-		ata_host_activate(host, IRQ_AMIGA_PORTS, ata_sff_interrupt,
-				  IRQF_SHARED, &pata_buddha_sht);
+		ap->private_data = (void *)irqport;
 
+		ata_port_desc(ap, "cmd 0x%lx ctl 0x%lx", board,
+			      ctl ? board + buddha_bases[i] + ctl : 0);
 	}
 
+	ata_host_activate(host, IRQ_AMIGA_PORTS, ata_sff_interrupt,
+			  IRQF_SHARED, &pata_buddha_sht);
+
+
 	return 0;
 }
 
-module_init(pata_buddha_init_one);
+static void pata_buddha_remove(struct zorro_dev *z)
+{
+	struct ata_host *host = dev_get_drvdata(&z->dev);
+
+	ata_host_detach(host);
+}
+
+static const struct zorro_device_id pata_buddha_zorro_tbl[] = {
+	{ ZORRO_PROD_INDIVIDUAL_COMPUTERS_BUDDHA, BOARD_BUDDHA},
+	{ ZORRO_PROD_INDIVIDUAL_COMPUTERS_CATWEASEL, BOARD_CATWEASEL},
+	/* { ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, BOARD_XSURF}, */
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(zorro, pata_buddha_zorro_tbl);
+
+static struct zorro_driver pata_buddha_driver = {
+	.name           = "pata_buddha",
+	.id_table       = pata_buddha_zorro_tbl,
+	.probe          = pata_buddha_probe,
+	.remove         = pata_buddha_remove,
+};
+
+
+
+/*
+ * We cannot have a modalias for X-Surf boards, as it competes with the
+ * zorro8390 network driver. As a stopgap measure until we have proper
+ * MFC support for this board, we manually attach to it late after Zorro
+ * has enumerated its boards.
+ */
+static int __init pata_buddha_late_init(void)
+{
+        struct zorro_dev *z = NULL;
+
+	pr_info("pata_buddha: Scanning for stand-alone IDE controllers...\n");
+	zorro_register_driver(&pata_buddha_driver);
+
+	pr_info("pata_buddha: Scanning for X-Surf boards...\n");
+        while ((z = zorro_find_device(ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, z))) {
+		static struct zorro_device_id xsurf_ent =
+			{ ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, BOARD_XSURF};
+
+		pata_buddha_probe(z, &xsurf_ent);
+        }
+
+        return 0;
+}
+
+static void __exit pata_buddha_exit(void)
+{
+	struct zorro_dev *z = NULL;
+
+	pr_info("pata_buddha: Releasing X-Surf boards...\n");
+        while ((z = zorro_find_device(ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, z))) {
+		struct ata_host *host = dev_get_drvdata(&z->dev);
+
+		if (host)
+			ata_host_detach(host);
+        }
+
+	pr_info("pata_buddha: Releasing stand-alone IDE controllers...\n");
+        zorro_unregister_driver(&pata_buddha_driver);
+}
+
+late_initcall(pata_buddha_late_init);
+module_exit(pata_buddha_exit);
+
 
 MODULE_AUTHOR("Bartlomiej Zolnierkiewicz");
 MODULE_DESCRIPTION("low-level driver for Buddha/Catweasel/X-Surf PATA");
-- 
2.11.0


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-11 15:36 [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall Max Staudt
@ 2019-08-11 15:40 ` Max Staudt
  2019-08-11 19:28 ` Max Staudt
  1 sibling, 0 replies; 9+ messages in thread
From: Max Staudt @ 2019-08-11 15:40 UTC (permalink / raw)
  To: b.zolnierkie, axboe
  Cc: linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert

Hi all,

Thank you for your reviews. I hope this patch fixes all issues that have been raised. In case I've missed something, please let me know.

Unfortunately I can't test the X-Surf part, as I don't own that board. I would be grateful for extra careful review of that part.


Max


^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-11 15:36 [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall Max Staudt
  2019-08-11 15:40 ` Max Staudt
@ 2019-08-11 19:28 ` Max Staudt
  2019-08-12 10:42   ` Bartlomiej Zolnierkiewicz
  1 sibling, 1 reply; 9+ messages in thread
From: Max Staudt @ 2019-08-11 19:28 UTC (permalink / raw)
  To: b.zolnierkie, axboe
  Cc: linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert

Replying to my own patch with two more questions:


On 08/11/2019 05:36 PM, Max Staudt wrote:
> -		/* allocate host */
> -		host = ata_host_alloc(&z->dev, nr_ports);

Actually, this is an issue even the existing pata_buddha has: ata_host_alloc() will dev_set_drvdata(dev, host) which is fine on Buddha and Catweasel, but conflicts with zorro8390's own dev_set_drvdata() on an X-Surf board. Thus, if both pata_buddha and zorro8390 are active, only one can be unloaded. The original ide/buddha driver does not have this problem as far as I can see.

This should be resolved once we get around to MFD support, as Geert suggested.

Shall we leave this as-is, as it's not really a change from the status quo in pata_buddha?


> +static int __init pata_buddha_late_init(void)
> +{
> +        struct zorro_dev *z = NULL;
> +
> +	pr_info("pata_buddha: Scanning for stand-alone IDE controllers...\n");
> +	zorro_register_driver(&pata_buddha_driver);
> +
> +	pr_info("pata_buddha: Scanning for X-Surf boards...\n");
> +        while ((z = zorro_find_device(ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, z))) {
> +		static struct zorro_device_id xsurf_ent =
> +			{ ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, BOARD_XSURF};
> +
> +		pata_buddha_probe(z, &xsurf_ent);
> +        }
> +
> +        return 0;
> +}

This is suboptimal, as we don't release memory in case pata_buddha_probe() fails. Any suggestions?


> +static void __exit pata_buddha_exit(void)
> +{
> +	struct zorro_dev *z = NULL;
> +
> +	pr_info("pata_buddha: Releasing X-Surf boards...\n");
> +        while ((z = zorro_find_device(ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, z))) {
> +		struct ata_host *host = dev_get_drvdata(&z->dev);
> +
> +		if (host)
> +			ata_host_detach(host);
> +        }

I guess that here we also need to manually release the resources we allocated with devm_* above. Any ideas?


Thanks

Max

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-11 19:28 ` Max Staudt
@ 2019-08-12 10:42   ` Bartlomiej Zolnierkiewicz
  2019-08-12 10:55     ` Max Staudt
  0 siblings, 1 reply; 9+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2019-08-12 10:42 UTC (permalink / raw)
  To: Max Staudt
  Cc: axboe, linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert


On 8/11/19 9:28 PM, Max Staudt wrote:
> Replying to my own patch with two more questions:
> 
> 
> On 08/11/2019 05:36 PM, Max Staudt wrote:
>> -		/* allocate host */
>> -		host = ata_host_alloc(&z->dev, nr_ports);
> 
> Actually, this is an issue even the existing pata_buddha has: ata_host_alloc()> will dev_set_drvdata(dev, host) which is fine on Buddha and Catweasel, bu> conflicts with zorro8390's own dev_set_drvdata() on an X-Surf board. Thus,
> if both pata_buddha and zorro8390 are active, only one can be unloaded. The
> original ide/buddha driver does not have this problem as far as I can see.

ide/buddha driver cannot be unloaded currently (it lacks module_exit()).

> This should be resolved once we get around to MFD support, as Geert suggested.
> 
> Shall we leave this as-is, as it's not really a change from the status quo in
> pata_buddha?
pata_buddha also cannot be unloaded currently (also lacks module_exit()),
I think that we should leave it as it is until MFD support is added.

>> +static int __init pata_buddha_late_init(void)
>> +{
>> +        struct zorro_dev *z = NULL;
>> +
>> +	pr_info("pata_buddha: Scanning for stand-alone IDE controllers...\n");
>> +	zorro_register_driver(&pata_buddha_driver);
>> +
>> +	pr_info("pata_buddha: Scanning for X-Surf boards...\n");
>> +        while ((z = zorro_find_device(ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, z))) {
>> +		static struct zorro_device_id xsurf_ent =
>> +			{ ZORRO_PROD_INDIVIDUAL_COMPUTERS_X_SURF, BOARD_XSURF};
>> +
>> +		pata_buddha_probe(z, &xsurf_ent);
>> +        }
>> +
>> +        return 0;
>> +}
> 
> This is suboptimal, as we don't release memory in case pata_buddha_probe()
> fails. Any suggestions?

It should work exactly like the old code in case of X-Surf,
what do we need to release?

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-12 10:42   ` Bartlomiej Zolnierkiewicz
@ 2019-08-12 10:55     ` Max Staudt
  2019-08-12 12:15       ` Bartlomiej Zolnierkiewicz
  0 siblings, 1 reply; 9+ messages in thread
From: Max Staudt @ 2019-08-12 10:55 UTC (permalink / raw)
  To: Bartlomiej Zolnierkiewicz
  Cc: axboe, linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert

Hi Bartlomiej,

Thanks for your feedback!


On 08/12/2019 12:42 PM, Bartlomiej Zolnierkiewicz wrote:
> 
> ide/buddha driver cannot be unloaded currently (it lacks module_exit()).
> 
> [... snip ...]
> 
> It should work exactly like the old code in case of X-Surf,
> what do we need to release?


So what shall I do? Once an X-Surf has been detected, we refuse to unload, and therefore we never have to release X-Surf resources? That would simplify things a lot.

What's a good way to do that, given that we now have module_exit() defined and an exit function is void?


Thanks,
Max

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-12 10:55     ` Max Staudt
@ 2019-08-12 12:15       ` Bartlomiej Zolnierkiewicz
  2019-08-12 14:26         ` Max Staudt
  0 siblings, 1 reply; 9+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2019-08-12 12:15 UTC (permalink / raw)
  To: Max Staudt
  Cc: axboe, linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert


On 8/12/19 12:55 PM, Max Staudt wrote:
> Hi Bartlomiej,
> 
> Thanks for your feedback!

Hi Max,

> On 08/12/2019 12:42 PM, Bartlomiej Zolnierkiewicz wrote:
>>
>> ide/buddha driver cannot be unloaded currently (it lacks module_exit()).
>>
>> [... snip ...]
>>
>> It should work exactly like the old code in case of X-Surf,
>> what do we need to release?
> 
> 
> So what shall I do? Once an X-Surf has been detected, we refuse to
> unload, and therefore we never have to release X-Surf resources?
> That would simplify things a lot.

Yes, it seems to be a simplest solution.

> What's a good way to do that, given that we now have module_exit()> defined and an exit function is void?

What about something like this:

static bool xsurf_present;
...
static int __init pata_buddha_late_init(void)
...
		if (pata_buddha_probe(z, &xsurf_ent) == 0 &&
		    xsurf_present == false)
			xsurf_present = true;
...
static void __exit pata_buddha_exit(void)
...
	if (xsurf_present)
		return -EBUSY;
...

?

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-12 12:15       ` Bartlomiej Zolnierkiewicz
@ 2019-08-12 14:26         ` Max Staudt
  2019-08-12 15:01           ` Bartlomiej Zolnierkiewicz
  0 siblings, 1 reply; 9+ messages in thread
From: Max Staudt @ 2019-08-12 14:26 UTC (permalink / raw)
  To: Bartlomiej Zolnierkiewicz
  Cc: axboe, linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert

On 08/12/2019 02:15 PM, Bartlomiej Zolnierkiewicz wrote:
>> What's a good way to do that, given that we now have module_exit()> defined and an exit function is void?
> 
> What about something like this:
> 
> static bool xsurf_present;
> ...
> static int __init pata_buddha_late_init(void)
> ...
> 		if (pata_buddha_probe(z, &xsurf_ent) == 0 &&
> 		    xsurf_present == false)
> 			xsurf_present = true;
> ...
> static void __exit pata_buddha_exit(void)
> ...
> 	if (xsurf_present)
> 		return -EBUSY;
> ...
> 
> ?

Okay, so we're talking about the same idea. Great!

Unfortunately, pata_buddha_exit() is void, and thus can't fail. According to Documentation/kernel-hacking/hacking.rst this is by design.

Any other ideas? We could also continue to disallow unloading completely until MFD support comes along.


Max

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-12 14:26         ` Max Staudt
@ 2019-08-12 15:01           ` Bartlomiej Zolnierkiewicz
  2019-08-12 15:39             ` Max Staudt
  0 siblings, 1 reply; 9+ messages in thread
From: Bartlomiej Zolnierkiewicz @ 2019-08-12 15:01 UTC (permalink / raw)
  To: Max Staudt
  Cc: axboe, linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert


On 8/12/19 4:26 PM, Max Staudt wrote:
> On 08/12/2019 02:15 PM, Bartlomiej Zolnierkiewicz wrote:
>>> What's a good way to do that, given that we now have module_exit()> defined and an exit function is void?
>>
>> What about something like this:
>>
>> static bool xsurf_present;
>> ...
>> static int __init pata_buddha_late_init(void)
>> ...
>> 		if (pata_buddha_probe(z, &xsurf_ent) == 0 &&
>> 		    xsurf_present == false)
>> 			xsurf_present = true;
>> ...
>> static void __exit pata_buddha_exit(void)
>> ...
>> 	if (xsurf_present)
>> 		return -EBUSY;
>> ...
>>
>> ?
> 
> Okay, so we're talking about the same idea. Great!
> 
> Unfortunately, pata_buddha_exit() is void, and thus can't fail. According to Documentation/kernel-hacking/hacking.rst this is by design.

You are of course right and the example code is broken
(+ I need more caffeine).

> Any other ideas? We could also continue to disallow unloading completely until MFD support comes along.
Yes, this would also be OK.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall
  2019-08-12 15:01           ` Bartlomiej Zolnierkiewicz
@ 2019-08-12 15:39             ` Max Staudt
  0 siblings, 0 replies; 9+ messages in thread
From: Max Staudt @ 2019-08-12 15:39 UTC (permalink / raw)
  To: Bartlomiej Zolnierkiewicz
  Cc: axboe, linux-ide, linux-m68k, linux-kernel, glaubitz, schmitzmic, geert

On 08/12/2019 05:01 PM, Bartlomiej Zolnierkiewicz wrote:
>> Unfortunately, pata_buddha_exit() is void, and thus can't fail. According to Documentation/kernel-hacking/hacking.rst this is by design.
> 
> You are of course right and the example code is broken
> (+ I need more caffeine).

Hey! That's usually my line to say!

I'm just glad I didn't miss something obvious here...


>> Any other ideas? We could also continue to disallow unloading completely until MFD support comes along.
> Yes, this would also be OK.

Okay, I will refresh the patch accordingly.

Thanks for your help!
Max

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, back to index

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-11 15:36 [PATCH v4] ata/pata_buddha: Probe via modalias instead of initcall Max Staudt
2019-08-11 15:40 ` Max Staudt
2019-08-11 19:28 ` Max Staudt
2019-08-12 10:42   ` Bartlomiej Zolnierkiewicz
2019-08-12 10:55     ` Max Staudt
2019-08-12 12:15       ` Bartlomiej Zolnierkiewicz
2019-08-12 14:26         ` Max Staudt
2019-08-12 15:01           ` Bartlomiej Zolnierkiewicz
2019-08-12 15:39             ` Max Staudt

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