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From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: linux-mtd@lists.infradead.org, kbuild-all@lists.01.org,
	kernel test robot <lkp@intel.com>,
	Serge Semin <fancer.lancer@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast removes address space '__iomem' of expression
Date: Thu, 12 Nov 2020 09:27:15 +0100	[thread overview]
Message-ID: <20201112092715.7e466405@xps13> (raw)
In-Reply-To: <20201111192259.ovdyjcuue7fx2bqa@mobilestation>

Hi Sergey,

Serge Semin <Sergey.Semin@baikalelectronics.ru> wrote on Wed, 11 Nov
2020 22:22:59 +0300:

> On Tue, Nov 10, 2020 at 04:35:56PM +0100, Miquel Raynal wrote:
> > Hi Serge,
> > 
> > Serge Semin <Sergey.Semin@baikalelectronics.ru> wrote on Tue, 10 Nov
> > 2020 14:38:27 +0300:
> >   
> > > Hello Miquel,
> > > 
> > > A situation noted by the warning below won't cause any problem because
> > > the casting is done to a non-dereferenced variable. It is utilized
> > > as a pointer bias later in that function. Shall we just ignore the
> > > warning or still fix it somehow?  
> >   
> 
> > Do you think the cast to a !__iomem value is mandatory here?  
> 
> It's not mandatory to have the casting with no __iomem, but wouldn't
> doing like this:
> + 	shift = (ssize_t __iomem)src & 0x3;
> be looking weird? Really, is there a good way to somehow extract the first
> two bits of a __iomem pointer without getting the sparse warning?

I asked around me, what about trying uintptr_t?

Thanks,
Miquèl

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

WARNING: multiple messages have this Message-ID (diff)
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: kbuild-all@lists.01.org
Subject: Re: drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast removes address space '__iomem' of expression
Date: Thu, 12 Nov 2020 09:27:15 +0100	[thread overview]
Message-ID: <20201112092715.7e466405@xps13> (raw)
In-Reply-To: <20201111192259.ovdyjcuue7fx2bqa@mobilestation>

[-- Attachment #1: Type: text/plain, Size: 1034 bytes --]

Hi Sergey,

Serge Semin <Sergey.Semin@baikalelectronics.ru> wrote on Wed, 11 Nov
2020 22:22:59 +0300:

> On Tue, Nov 10, 2020 at 04:35:56PM +0100, Miquel Raynal wrote:
> > Hi Serge,
> > 
> > Serge Semin <Sergey.Semin@baikalelectronics.ru> wrote on Tue, 10 Nov
> > 2020 14:38:27 +0300:
> >   
> > > Hello Miquel,
> > > 
> > > A situation noted by the warning below won't cause any problem because
> > > the casting is done to a non-dereferenced variable. It is utilized
> > > as a pointer bias later in that function. Shall we just ignore the
> > > warning or still fix it somehow?  
> >   
> 
> > Do you think the cast to a !__iomem value is mandatory here?  
> 
> It's not mandatory to have the casting with no __iomem, but wouldn't
> doing like this:
> + 	shift = (ssize_t __iomem)src & 0x3;
> be looking weird? Really, is there a good way to somehow extract the first
> two bits of a __iomem pointer without getting the sparse warning?

I asked around me, what about trying uintptr_t?

Thanks,
Miquèl

WARNING: multiple messages have this Message-ID (diff)
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Serge Semin <fancer.lancer@gmail.com>,
	kernel test robot <lkp@intel.com>, <kbuild-all@lists.01.org>,
	<linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>
Subject: Re: drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast removes address space '__iomem' of expression
Date: Thu, 12 Nov 2020 09:27:15 +0100	[thread overview]
Message-ID: <20201112092715.7e466405@xps13> (raw)
In-Reply-To: <20201111192259.ovdyjcuue7fx2bqa@mobilestation>

Hi Sergey,

Serge Semin <Sergey.Semin@baikalelectronics.ru> wrote on Wed, 11 Nov
2020 22:22:59 +0300:

> On Tue, Nov 10, 2020 at 04:35:56PM +0100, Miquel Raynal wrote:
> > Hi Serge,
> > 
> > Serge Semin <Sergey.Semin@baikalelectronics.ru> wrote on Tue, 10 Nov
> > 2020 14:38:27 +0300:
> >   
> > > Hello Miquel,
> > > 
> > > A situation noted by the warning below won't cause any problem because
> > > the casting is done to a non-dereferenced variable. It is utilized
> > > as a pointer bias later in that function. Shall we just ignore the
> > > warning or still fix it somehow?  
> >   
> 
> > Do you think the cast to a !__iomem value is mandatory here?  
> 
> It's not mandatory to have the casting with no __iomem, but wouldn't
> doing like this:
> + 	shift = (ssize_t __iomem)src & 0x3;
> be looking weird? Really, is there a good way to somehow extract the first
> two bits of a __iomem pointer without getting the sparse warning?

I asked around me, what about trying uintptr_t?

Thanks,
Miquèl

  reply	other threads:[~2020-11-12  8:28 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-02  4:42 drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast removes address space '__iomem' of expression kernel test robot
2020-11-02  4:42 ` kernel test robot
2020-11-10 11:38 ` Serge Semin
2020-11-10 11:38   ` Serge Semin
2020-11-10 11:38   ` Serge Semin
2020-11-10 15:35   ` Miquel Raynal
2020-11-10 15:35     ` Miquel Raynal
2020-11-10 15:35     ` Miquel Raynal
2020-11-11 19:22     ` Serge Semin
2020-11-11 19:22       ` Serge Semin
2020-11-11 19:22       ` Serge Semin
2020-11-12  8:27       ` Miquel Raynal [this message]
2020-11-12  8:27         ` Miquel Raynal
2020-11-12  8:27         ` Miquel Raynal
2020-11-12 11:20         ` Serge Semin
2020-11-12 11:20           ` Serge Semin
2020-11-12 11:20           ` Serge Semin
2020-11-12 15:00         ` Vignesh Raghavendra
2020-11-12 15:00           ` Vignesh Raghavendra
2020-11-12 15:00           ` Vignesh Raghavendra
2020-11-12 15:27           ` Serge Semin
2020-11-12 15:27             ` Serge Semin
2020-11-12 15:27             ` Serge Semin
2020-11-12 15:43             ` Miquel Raynal
2020-11-12 15:43               ` Miquel Raynal
2020-11-12 15:43               ` Miquel Raynal
2020-11-12 16:10               ` Serge Semin
2020-11-12 16:10                 ` Serge Semin
2020-11-12 16:10                 ` Serge Semin
2020-11-12 16:15                 ` Miquel Raynal
2020-11-12 16:15                   ` Miquel Raynal
2020-11-12 16:15                   ` Miquel Raynal
2020-11-12 16:21                   ` Serge Semin
2020-11-12 16:21                     ` Serge Semin
2020-11-12 16:21                     ` Serge Semin

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