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Subject[PATCH 3/4] hpsa: get rid of compat_alloc_user_space()
Date
From: Al Viro <viro@zeniv.linux.org.uk>

no need for building a native struct on kernel stack, copying
it to userland one, then calling hpsa_ioctl() which copies it
back into _another_ instance of the same struct.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
drivers/scsi/hpsa.c | 80 ++++++++++++++++++++++++-----------------------------
1 file changed, 36 insertions(+), 44 deletions(-)

diff --git a/drivers/scsi/hpsa.c b/drivers/scsi/hpsa.c
index 64fd97272109..c7fbe56891ef 100644
--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -254,6 +254,10 @@ static irqreturn_t do_hpsa_intr_intx(int irq, void *dev_id);
static irqreturn_t do_hpsa_intr_msi(int irq, void *dev_id);
static int hpsa_ioctl(struct scsi_device *dev, unsigned int cmd,
void __user *arg);
+static int hpsa_passthru_ioctl(struct ctlr_info *h,
+ IOCTL_Command_struct *iocommand);
+static int hpsa_big_passthru_ioctl(struct ctlr_info *h,
+ BIG_IOCTL_Command_struct *ioc);

#ifdef CONFIG_COMPAT
static int hpsa_compat_ioctl(struct scsi_device *dev, unsigned int cmd,
@@ -6217,75 +6221,63 @@ static void cmd_free(struct ctlr_info *h, struct CommandList *c)
static int hpsa_ioctl32_passthru(struct scsi_device *dev, unsigned int cmd,
void __user *arg)
{
- IOCTL32_Command_struct __user *arg32 =
- (IOCTL32_Command_struct __user *) arg;
+ struct ctlr_info *h = sdev_to_hba(dev);
+ IOCTL32_Command_struct __user *arg32 = arg;
IOCTL_Command_struct arg64;
- IOCTL_Command_struct __user *p = compat_alloc_user_space(sizeof(arg64));
int err;
u32 cp;

- memset(&arg64, 0, sizeof(arg64));
- err = 0;
- err |= copy_from_user(&arg64.LUN_info, &arg32->LUN_info,
- sizeof(arg64.LUN_info));
- err |= copy_from_user(&arg64.Request, &arg32->Request,
- sizeof(arg64.Request));
- err |= copy_from_user(&arg64.error_info, &arg32->error_info,
- sizeof(arg64.error_info));
- err |= get_user(arg64.buf_size, &arg32->buf_size);
- err |= get_user(cp, &arg32->buf);
- arg64.buf = compat_ptr(cp);
- err |= copy_to_user(p, &arg64, sizeof(arg64));
+ if (!arg)
+ return -EINVAL;

- if (err)
+ memset(&arg64, 0, sizeof(arg64));
+ if (copy_from_user(&arg64, arg32, offsetof(IOCTL_Command_struct, buf)))
+ return -EFAULT;
+ if (get_user(cp, &arg32->buf))
return -EFAULT;
+ arg64.buf = compat_ptr(cp);

- err = hpsa_ioctl(dev, CCISS_PASSTHRU, p);
+ if (atomic_dec_if_positive(&h->passthru_cmds_avail) < 0)
+ return -EAGAIN;
+ err = hpsa_passthru_ioctl(h, &arg64);
+ atomic_inc(&h->passthru_cmds_avail);
if (err)
return err;
- err |= copy_in_user(&arg32->error_info, &p->error_info,
- sizeof(arg32->error_info));
- if (err)
+ if (copy_to_user(&arg32->error_info, &arg64.error_info,
+ sizeof(arg32->error_info)))
return -EFAULT;
- return err;
+ return 0;
}

static int hpsa_ioctl32_big_passthru(struct scsi_device *dev,
unsigned int cmd, void __user *arg)
{
- BIG_IOCTL32_Command_struct __user *arg32 =
- (BIG_IOCTL32_Command_struct __user *) arg;
+ struct ctlr_info *h = sdev_to_hba(dev);
+ BIG_IOCTL32_Command_struct __user *arg32 = arg;
BIG_IOCTL_Command_struct arg64;
- BIG_IOCTL_Command_struct __user *p =
- compat_alloc_user_space(sizeof(arg64));
int err;
u32 cp;

+ if (!arg)
+ return -EINVAL;
memset(&arg64, 0, sizeof(arg64));
- err = 0;
- err |= copy_from_user(&arg64.LUN_info, &arg32->LUN_info,
- sizeof(arg64.LUN_info));
- err |= copy_from_user(&arg64.Request, &arg32->Request,
- sizeof(arg64.Request));
- err |= copy_from_user(&arg64.error_info, &arg32->error_info,
- sizeof(arg64.error_info));
- err |= get_user(arg64.buf_size, &arg32->buf_size);
- err |= get_user(arg64.malloc_size, &arg32->malloc_size);
- err |= get_user(cp, &arg32->buf);
- arg64.buf = compat_ptr(cp);
- err |= copy_to_user(p, &arg64, sizeof(arg64));
-
- if (err)
+ if (copy_from_user(&arg64, arg32,
+ offsetof(BIG_IOCTL32_Command_struct, buf)))
return -EFAULT;
+ if (get_user(cp, &arg32->buf))
+ return -EFAULT;
+ arg64.buf = compat_ptr(cp);

- err = hpsa_ioctl(dev, CCISS_BIG_PASSTHRU, p);
+ if (atomic_dec_if_positive(&h->passthru_cmds_avail) < 0)
+ return -EAGAIN;
+ err = hpsa_big_passthru_ioctl(h, &arg64);
+ atomic_inc(&h->passthru_cmds_avail);
if (err)
return err;
- err |= copy_in_user(&arg32->error_info, &p->error_info,
- sizeof(arg32->error_info));
- if (err)
+ if (copy_to_user(&arg32->error_info, &arg64.error_info,
+ sizeof(arg32->error_info)))
return -EFAULT;
- return err;
+ return 0;
}

static int hpsa_compat_ioctl(struct scsi_device *dev, unsigned int cmd,
--
2.11.0
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