Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1240979 > unrolled thread

[PATCH] nvme: fix 32-bit build warning

Back to article view | Back to linux.kernel

Contents

  [PATCH] nvme: fix 32-bit build warning Arnd Bergmann <arnd@arndb.de> - 2015-10-06 22:40 +0200
    Re: [PATCH] nvme: fix 32-bit build warning Christoph Hellwig <hch@infradead.org> - 2015-10-09 16:50 +0200
      [PATCH v2] nvme: fix 32-bit build warning Arnd Bergmann <arnd@arndb.de> - 2015-10-09 21:00 +0200
        Re: [PATCH v2] nvme: fix 32-bit build warning Christoph Hellwig <hch@lst.de> - 2015-10-12 21:10 +0200
          Re: [PATCH v2] nvme: fix 32-bit build warning Jens Axboe <axboe@fb.com> - 2015-10-12 21:20 +0200
            Re: [PATCH v2] nvme: fix 32-bit build warning Arnd Bergmann <arnd@arndb.de> - 2015-10-12 21:20 +0200
              Re: [PATCH v2] nvme: fix 32-bit build warning Jens Axboe <axboe@fb.com> - 2015-10-12 21:30 +0200
      Re: [PATCH] nvme: fix 32-bit build warning Arnd Bergmann <arnd@arndb.de> - 2015-10-09 21:00 +0200

#1240979 — [PATCH] nvme: fix 32-bit build warning

Compiling the nvme driver on 32-bit warns about a cast from a __u64
variable to a pointer:

drivers/block/nvme-core.c: In function 'nvme_submit_io':
drivers/block/nvme-core.c:1847:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    (void __user *)io.addr, length, NULL, 0);

The cast here is intentional and safe, so we can shut up the
gcc warning by adding an intermediate cast to 'unsigned long'.

I had previously submitted a patch to fix this problem in the
nvme driver, but it was accepted on the same day that two new
warnings got added.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: d29ec8241c10e ("nvme: submit internal commands through the block layer")

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index e917cf304ad0..f9faf276ce74 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1844,7 +1844,7 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 	c.rw.metadata = cpu_to_le64(meta_dma);
 
 	status = __nvme_submit_sync_cmd(ns->queue, &c, NULL,
-			(void __user *)io.addr, length, NULL, 0);
+			(void __user *)(unsigned long)io.addr, length, NULL, 0);
  unmap:
 	if (meta) {
 		if (status == NVME_SC_SUCCESS && !write) {
@@ -1886,7 +1886,7 @@ static int nvme_user_cmd(struct nvme_dev *dev, struct nvme_ns *ns,
 		timeout = msecs_to_jiffies(cmd.timeout_ms);
 
 	status = __nvme_submit_sync_cmd(ns ? ns->queue : dev->admin_q, &c,
-			NULL, (void __user *)cmd.addr, cmd.data_len,
+			NULL, (void __user *)(unsigned long)cmd.addr, cmd.data_len,
 			&cmd.result, timeout);
 	if (status >= 0) {
 		if (put_user(cmd.result, &ucmd->result))

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1243446

On Tue, Oct 06, 2015 at 10:37:11PM +0200, Arnd Bergmann wrote:
> Compiling the nvme driver on 32-bit warns about a cast from a __u64
> variable to a pointer:
> 
> drivers/block/nvme-core.c: In function 'nvme_submit_io':
> drivers/block/nvme-core.c:1847:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>     (void __user *)io.addr, length, NULL, 0);
> 
> The cast here is intentional and safe, so we can shut up the
> gcc warning by adding an intermediate cast to 'unsigned long'.

It really should be a uintptr_t, which would also avoid the > 80
character lines.  I wonder if we need a u64_to_ptr helper given these
ioctl ABIs that pass pointers as a u64 seems to be everywhere these
days.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1243610 — [PATCH v2] nvme: fix 32-bit build warning

From 877a323df080bda54a71e26ecf20b4244b31a180 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Tue, 6 Oct 2015 22:29:48 +0200
Subject: [PATCH] nvme: fix 32-bit build warning

Compiling the nvme driver on 32-bit warns about a cast from a __u64
variable to a pointer:

drivers/block/nvme-core.c: In function 'nvme_submit_io':
drivers/block/nvme-core.c:1847:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    (void __user *)io.addr, length, NULL, 0);

The cast here is intentional and safe, so we can shut up the
gcc warning by adding an intermediate cast to 'uintptr_t'.

I had previously submitted a patch to fix this problem in the
nvme driver, but it was accepted on the same day that two new
warnings got added.

For clarification, I also change the third instance of this cast
to use uintptr_t instead of unsigned long now.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: d29ec8241c10e ("nvme: submit internal commands through the block layer")
---
v2: use uintptr_t for intermediate cast

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index e917cf304ad0..e8ff16c63977 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1804,7 +1804,7 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 
 	length = (io.nblocks + 1) << ns->lba_shift;
 	meta_len = (io.nblocks + 1) * ns->ms;
-	metadata = (void __user *)(unsigned long)io.metadata;
+	metadata = (void __user *)(uintptr_t)io.metadata;
 	write = io.opcode & 1;
 
 	if (ns->ext) {
@@ -1844,7 +1844,7 @@ static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
 	c.rw.metadata = cpu_to_le64(meta_dma);
 
 	status = __nvme_submit_sync_cmd(ns->queue, &c, NULL,
-			(void __user *)io.addr, length, NULL, 0);
+			(void __user *)(uintptr_t)io.addr, length, NULL, 0);
  unmap:
 	if (meta) {
 		if (status == NVME_SC_SUCCESS && !write) {
@@ -1886,7 +1886,7 @@ static int nvme_user_cmd(struct nvme_dev *dev, struct nvme_ns *ns,
 		timeout = msecs_to_jiffies(cmd.timeout_ms);
 
 	status = __nvme_submit_sync_cmd(ns ? ns->queue : dev->admin_q, &c,
-			NULL, (void __user *)cmd.addr, cmd.data_len,
+			NULL, (void __user *)(uintptr_t)cmd.addr, cmd.data_len,
 			&cmd.result, timeout);
 	if (status >= 0) {
 		if (put_user(cmd.result, &ucmd->result))

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1245039 — Re: [PATCH v2] nvme: fix 32-bit build warning

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

Note that we're moved the nvme driver to a new directory in the
block tree, but I can rebase it for you if you want.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1245044 — Re: [PATCH v2] nvme: fix 32-bit build warning

On 10/12/2015 01:03 PM, Christoph Hellwig wrote:
> Looks good,
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
>
> Note that we're moved the nvme driver to a new directory in the
> block tree, but I can rebase it for you if you want.

I man handled it on both branches, so we should be good.


-- 
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1245052 — Re: [PATCH v2] nvme: fix 32-bit build warning

On Monday 12 October 2015 13:10:17 Jens Axboe wrote:
> On 10/12/2015 01:03 PM, Christoph Hellwig wrote:
> > Looks good,
> >
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> >
> > Note that we're moved the nvme driver to a new directory in the
> > block tree, but I can rebase it for you if you want.
> 
> I man handled it on both branches, so we should be good.

Thanks! I already saw the move, and it caused another build error
when CONFIG_BLOCK is disabled. Do you have this one?

	Arnd

diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
index 0089f78b4071..002a94abdbc4 100644
--- a/drivers/nvme/host/Kconfig
+++ b/drivers/nvme/host/Kconfig
@@ -1,6 +1,6 @@
 config BLK_DEV_NVME
 	tristate "NVM Express block device"
-	depends on PCI
+	depends on PCI && BLOCK
 	---help---
 	  The NVM Express driver is for solid state drives directly
 	  connected to the PCI or PCI Express bus.  If you know you

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1245059 — Re: [PATCH v2] nvme: fix 32-bit build warning

On 10/12/2015 01:14 PM, Arnd Bergmann wrote:
> On Monday 12 October 2015 13:10:17 Jens Axboe wrote:
>> On 10/12/2015 01:03 PM, Christoph Hellwig wrote:
>>> Looks good,
>>>
>>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>>>
>>> Note that we're moved the nvme driver to a new directory in the
>>> block tree, but I can rebase it for you if you want.
>>
>> I man handled it on both branches, so we should be good.
>
> Thanks! I already saw the move, and it caused another build error
> when CONFIG_BLOCK is disabled. Do you have this one?

I do, Keith sent that one in earlier today, it's in the 4.4 branch.

-- 
Jens Axboe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1243613

On Friday 09 October 2015 07:42:21 Christoph Hellwig wrote:
> On Tue, Oct 06, 2015 at 10:37:11PM +0200, Arnd Bergmann wrote:
> > Compiling the nvme driver on 32-bit warns about a cast from a __u64
> > variable to a pointer:
> > 
> > drivers/block/nvme-core.c: In function 'nvme_submit_io':
> > drivers/block/nvme-core.c:1847:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
> >     (void __user *)io.addr, length, NULL, 0);
> > 
> > The cast here is intentional and safe, so we can shut up the
> > gcc warning by adding an intermediate cast to 'unsigned long'.
> 
> It really should be a uintptr_t, which would also avoid the > 80
> character lines.  I wonder if we need a u64_to_ptr helper given these
> ioctl ABIs that pass pointers as a u64 seems to be everywhere these
> days.

I'll send a new version with uintptr_t for now, but having a proper
interface for this sounds like a good idea.

I've seen a couple of cases like this, and most but not
all actually want a __user pointer like this one. That seems
similar to the common ioctl use case where we want a user pointer
from an 'unsigned long', so we could use the same function for both,
like

static inline void __user *get_uptr(unsigned long arg)
{
	return (void __user *)arg;
}

With this definition, you can pass any scalar type (u64 or
unsigned long normally) and get the pointer, and we can
put that into include/linux/uaccess.h.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web