[PATCH 1/4] scsi: pmcraid: use __iomem pointers for ioctl argument

Arnd Bergmann
2017-04-20T17:56:05Z

kernelci.org reports a new compile warning for old code in the pmcraid
driver:

arch/mips/include/asm/uaccess.h:138:21: warning: passing argument 1 of '__access_ok' makes pointer from integer without a cast [-Wint-conversion]

The warning got introduced by a cleanup to the access_ok() helper
that requires the argument to be a pointer, where the old version
silently accepts 'unsigned long' arguments as it still does on most
other architectures.

The new behavior in MIPS however seems absolutely sensible, and so far I
could only find one other file with the same issue, so the best solution
seems to be to clean up the pmcraid driver.

This makes the driver consistently use 'void __iomem *' pointers for
passing around the address of the user space ioctl arguments, which gets
rid of the kernelci warning as well as several sparse warnings.

Fixes: f0a955f4eeec ("mips: sanitize __access_ok()")
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I wanted to be sure that I get all the __iomem annotations right, so
I ended up fixing all other sparse warnings as well, see the three
follow-up patches.
---
drivers/scsi/pmcraid.c | 44 ++++++++++++++++----------------------------
1 file changed, 16 insertions(+), 28 deletions(-)

diff --git a/drivers/scsi/pmcraid.c b/drivers/scsi/pmcraid.c
index 49e70a383afa..096c704ca39a 100644
--- a/drivers/scsi/pmcraid.c
+++ b/drivers/scsi/pmcraid.c
@@ -3325,7 +3325,7 @@ static struct pmcraid_sglist *pmcraid_alloc_sglist(int buflen)
*/
static int pmcraid_copy_sglist(
struct pmcraid_sglist *sglist,
- unsigned long buffer,
+ void __user *buffer,
u32 len,
int direction
)
@@ -3346,11 +3346,9 @@ static int pmcraid_copy_sglist(

kaddr = kmap(page);
if (direction == DMA_TO_DEVICE)
- rc = __copy_from_user(kaddr,
- (void *)buffer,
- bsize_elem);
+ rc = __copy_from_user(kaddr, buffer, bsize_elem);
else
- rc = __copy_to_user((void *)buffer, kaddr, bsize_elem);
+ rc = __copy_to_user(buffer, kaddr, bsize_elem);

kunmap(page);

@@ -3368,13 +3366,9 @@ static int pmcraid_copy_sglist(
kaddr = kmap(page);

if (direction == DMA_TO_DEVICE)
- rc = __copy_from_user(kaddr,
- (void *)buffer,
- len % bsize_elem);
+ rc = __copy_from_user(kaddr, buffer, len % bsize_elem);
else
- rc = __copy_to_user((void *)buffer,
- kaddr,
- len % bsize_elem);
+ rc = __copy_to_user(buffer, kaddr, len % bsize_elem);

kunmap(page);

@@ -3652,17 +3646,17 @@ static long pmcraid_ioctl_passthrough(
struct pmcraid_instance *pinstance,
unsigned int ioctl_cmd,
unsigned int buflen,
- unsigned long arg
+ void __user *arg
)
{
struct pmcraid_passthrough_ioctl_buffer *buffer;
struct pmcraid_ioarcb *ioarcb;
struct pmcraid_cmd *cmd;
struct pmcraid_cmd *cancel_cmd;
- unsigned long request_buffer;
+ void __user *request_buffer;
unsigned long request_offset;
unsigned long lock_flags;
- void *ioasa;
+ void __user *ioasa;
u32 ioasc;
int request_size;
int buffer_size;
@@ -3701,13 +3695,10 @@ static long pmcraid_ioctl_passthrough(

request_buffer = arg + request_offset;

- rc = __copy_from_user(buffer,
- (struct pmcraid_passthrough_ioctl_buffer *) arg,
+ rc = __copy_from_user(buffer, arg,
sizeof(struct pmcraid_passthrough_ioctl_buffer));

- ioasa =
- (void *)(arg +
- offsetof(struct pmcraid_passthrough_ioctl_buffer, ioasa));
+ ioasa = arg + offsetof(struct pmcraid_passthrough_ioctl_buffer, ioasa);

if (rc) {
pmcraid_err("ioctl: can't copy passthrough buffer\n");
@@ -4021,6 +4012,7 @@ static long pmcraid_chr_ioctl(
{
struct pmcraid_instance *pinstance = NULL;
struct pmcraid_ioctl_header *hdr = NULL;
+ void __user *argp = (void __user *)arg;
int retval = -ENOTTY;

hdr = kmalloc(sizeof(struct pmcraid_ioctl_header), GFP_KERNEL);
@@ -4030,7 +4022,7 @@ static long pmcraid_chr_ioctl(
return -ENOMEM;
}

- retval = pmcraid_check_ioctl_buffer(cmd, (void *)arg, hdr);
+ retval = pmcraid_check_ioctl_buffer(cmd, argp, hdr);

if (retval) {
pmcraid_info("chr_ioctl: header check failed\n");
@@ -4055,10 +4047,8 @@ static long pmcraid_chr_ioctl(
if (cmd == PMCRAID_IOCTL_DOWNLOAD_MICROCODE)
scsi_block_requests(pinstance->host);

- retval = pmcraid_ioctl_passthrough(pinstance,
- cmd,
- hdr->buffer_length,
- arg);
+ retval = pmcraid_ioctl_passthrough(pinstance, cmd,
+ hdr->buffer_length, argp);

if (cmd == PMCRAID_IOCTL_DOWNLOAD_MICROCODE)
scsi_unblock_requests(pinstance->host);
@@ -4066,10 +4056,8 @@ static long pmcraid_chr_ioctl(

case PMCRAID_DRIVER_IOCTL:
arg += sizeof(struct pmcraid_ioctl_header);
- retval = pmcraid_ioctl_driver(pinstance,
- cmd,
- hdr->buffer_length,
- (void __user *)arg);
+ retval = pmcraid_ioctl_driver(pinstance, cmd,
+ hdr->buffer_length, argp);
break;

default:
--
2.9.0