[PATCH] mtd: m25p80: Make the name of mtd_info fixed

To give spi flash layout using "mtdparts=..." in cmdline, we must
give mtd_info a fixed name,because the cmdlinepart's parser will
match the name given in cmdline with the mtd_info.

Now, if use OF node, mtd_info's name will be spi->dev->name. It
consists of spi_master->bus_num, and the spi_master->bus_num maybe
dynamically fetched.
So, give the mtd_info a new fiexd name "name.cs", "name" is name of
spi_device_id and "cs" is chip-select in spi_dev.

Signed-off-by: Hou Zhiqiang <redacted>
---
 drivers/mtd/devices/m25p80.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index eb558e8..d1ed480 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c

@@ -1012,7 +1012,8 @@ static int m25p_probe(struct spi_device *spi)
 	if (data && data->name)
 		flash->mtd.name = data->name;
 	else
-		flash->mtd.name = dev_name(&spi->dev);
+		flash->mtd.name = kasprintf(GFP_KERNEL, "%s.%d",
+				id->name, spi->chip_select);
 
 	flash->mtd.type = MTD_NORFLASH;
 	flash->mtd.writesize = 1;

-- 
1.8.4.1

Hi Hou,

On Mon, Jan 06, 2014 at 02:34:29PM +0800, Hou Zhiqiang wrote:

Changing the mtd.name may have far-reaching consequences for users who
already have mtdparts= command lines. But your concern is probably valid
for dynamically-determined bus numbers. Perhaps you can edit this patch
to only change the name when the busnum is dynamically-allocated?

This also needs a NULL check (for OOM), and you leak memory on device
removal.

 
 	flash->mtd.type = MTD_NORFLASH;
 	flash->mtd.writesize = 1;

Brian

Hi Brian,
Thanks for your comments!

-----Original Message-----
From: Brian Norris [mailto:computersforpeace@gmail.com]
Sent: Thursday, January 23, 2014 10:12 AM
To: Hou Zhiqiang-B48286
Cc: linux-mtd@lists.infradead.org; linuxppc-dev@ozlabs.org; Wood Scott-
B07421; Hu Mingkai-B21284; Ezequiel Garcia
Subject: Re: [PATCH] mtd: m25p80: Make the name of mtd_info fixed
=20
Hi Hou,
=20
On Mon, Jan 06, 2014 at 02:34:29PM +0800, Hou Zhiqiang wrote:

quoted

To give spi flash layout using "mtdparts=3D..." in cmdline, we must giv=

e

quoted

mtd_info a fixed name,because the cmdlinepart's parser will match the
name given in cmdline with the mtd_info.

Now, if use OF node, mtd_info's name will be spi->dev->name. It
consists of spi_master->bus_num, and the spi_master->bus_num maybe
dynamically fetched.
So, give the mtd_info a new fiexd name "name.cs", "name" is name of
spi_device_id and "cs" is chip-select in spi_dev.

Signed-off-by: Hou Zhiqiang <redacted>
---
 drivers/mtd/devices/m25p80.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/m25p80.c

b/drivers/mtd/devices/m25p80.c index eb558e8..d1ed480 100644

--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c

@@ -1012,7 +1012,8 @@ static int m25p_probe(struct spi_device *spi)
 	if (data && data->name)
 		flash->mtd.name =3D data->name;
 	else
-		flash->mtd.name =3D dev_name(&spi->dev);
+		flash->mtd.name =3D kasprintf(GFP_KERNEL, "%s.%d",
+				id->name, spi->chip_select);

=20
Changing the mtd.name may have far-reaching consequences for users who
already have mtdparts=3D command lines. But your concern is probably vali=

d

for dynamically-determined bus numbers. Perhaps you can edit this patch
to only change the name when the busnum is dynamically-allocated?

It's a good idea, but in the case of mtd_info's name dynamically-allocated
using "mtdparts=3D..." in command lines is illegal obviously. Would you tel=
l
me what side-effect will be brought by the change of mtd_info's name.
Thanks=20
=20

This also needs a NULL check (for OOM), and you leak memory on device
removal.
=20

Yes, it's necessary to check the return value of function kasprintf.

quoted

 	flash->mtd.type =3D MTD_NORFLASH;
 	flash->mtd.writesize =3D 1;

=20
Brian
=20

Thanks,
Hou Zhiqiang

Hi Hou,

On Thu, Jan 23, 2014 at 03:29:41AM +0000, B48286@freescale.com wrote:

quoted

-----Original Message-----
From: Brian Norris [mailto:computersforpeace@gmail.com]
Sent: Thursday, January 23, 2014 10:12 AM
To: Hou Zhiqiang-B48286
Cc: linux-mtd@lists.infradead.org; linuxppc-dev@ozlabs.org; Wood Scott-
B07421; Hu Mingkai-B21284; Ezequiel Garcia
Subject: Re: [PATCH] mtd: m25p80: Make the name of mtd_info fixed

On Mon, Jan 06, 2014 at 02:34:29PM +0800, Hou Zhiqiang wrote:

quoted

--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c

@@ -1012,7 +1012,8 @@ static int m25p_probe(struct spi_device *spi)
 	if (data && data->name)
 		flash->mtd.name = data->name;
 	else
-		flash->mtd.name = dev_name(&spi->dev);
+		flash->mtd.name = kasprintf(GFP_KERNEL, "%s.%d",
+				id->name, spi->chip_select);

Changing the mtd.name may have far-reaching consequences for users who
already have mtdparts= command lines. But your concern is probably valid
for dynamically-determined bus numbers. Perhaps you can edit this patch
to only change the name when the busnum is dynamically-allocated?

It's a good idea, but in the case of mtd_info's name dynamically-allocated
using "mtdparts=..." in command lines is illegal obviously.

I agree that users should never have relied on the dynamically-allocated
name. But changing the name for non-dynamic schemes (e.g., where the SPI
busnum is a fixed value) is not pleasant for users.

Would you tell
me what side-effect will be brought by the change of mtd_info's name.

I can only think of the mtdparts= command line. Otherwise, I don't think
the name is very important.

Brian