[PATCHv2] NVMe: compat SG_IO ioctl

[keith.busch@intel.com (Keith Busch)]

For 32-bit versions of sg3-utils running on a 64-bit system. This is
mostly a copy from the relevent portions of fs/compat_ioctl.c, with
slight modifications for going through block_device_operations.

Signed-off-by: Keith Busch <keith.busch at intel.com>
---
v1->v2:

Added the copying the status back into the 32-bit user structure at the
end. I missed this when copying from the original implmenetation.

 drivers/block/nvme-core.c |   14 ++++-
 drivers/block/nvme-scsi.c |  146 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/nvme.h      |    1 +
 3 files changed, 160 insertions(+), 1 deletion(-)

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index da52092..2cb41df 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -1569,10 +1569,22 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd,
 	}
 }
 
+static int nvme_compat_ioctl(struct block_device *bdev, fmode_t mode,
+					unsigned int cmd, unsigned long arg)
+{
+	struct nvme_ns *ns = bdev->bd_disk->private_data;
+
+	switch (cmd) {
+	case SG_IO:
+		return nvme_sg_io32(ns, arg);
+	}
+	return nvme_ioctl(bdev, mode, cmd, arg);
+}
+
 static const struct block_device_operations nvme_fops = {
 	.owner		= THIS_MODULE,
 	.ioctl		= nvme_ioctl,
-	.compat_ioctl	= nvme_ioctl,
+	.compat_ioctl	= nvme_compat_ioctl,
 };
 
 static void nvme_resubmit_bios(struct nvme_queue *nvmeq)
diff --git a/drivers/block/nvme-scsi.c b/drivers/block/nvme-scsi.c
index 4a4ff4e..be04c50 100644
--- a/drivers/block/nvme-scsi.c
+++ b/drivers/block/nvme-scsi.c
@@ -25,6 +25,7 @@
 #include <linux/bio.h>
 #include <linux/bitops.h>
 #include <linux/blkdev.h>
+#include <linux/compat.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
 #include <linux/fs.h>
@@ -46,6 +47,7 @@
 #include <linux/types.h>
 #include <scsi/sg.h>
 #include <scsi/scsi.h>
+#include <asm/compat.h>
 
 
 static int sg_version_num = 30534;	/* 2 digits for each component */
@@ -3038,6 +3040,150 @@ int nvme_sg_io(struct nvme_ns *ns, struct sg_io_hdr __user *u_hdr)
 	return retcode;
 }
 
+typedef struct sg_io_hdr32 {
+	compat_int_t interface_id;	/* [i] 'S' for SCSI generic (required) */
+	compat_int_t dxfer_direction;	/* [i] data transfer direction  */
+	unsigned char cmd_len;		/* [i] SCSI command length ( <= 16 bytes) */
+	unsigned char mx_sb_len;		/* [i] max length to write to sbp */
+	unsigned short iovec_count;	/* [i] 0 implies no scatter gather */
+	compat_uint_t dxfer_len;		/* [i] byte count of data transfer */
+	compat_uint_t dxferp;		/* [i], [*io] points to data transfer memory
+					      or scatter gather list */
+	compat_uptr_t cmdp;		/* [i], [*i] points to command to perform */
+	compat_uptr_t sbp;		/* [i], [*o] points to sense_buffer memory */
+	compat_uint_t timeout;		/* [i] MAX_UINT->no timeout (unit: millisec) */
+	compat_uint_t flags;		/* [i] 0 -> default, see SG_FLAG... */
+	compat_int_t pack_id;		/* [i->o] unused internally (normally) */
+	compat_uptr_t usr_ptr;		/* [i->o] unused internally */
+	unsigned char status;		/* [o] scsi status */
+	unsigned char masked_status;	/* [o] shifted, masked scsi status */
+	unsigned char msg_status;		/* [o] messaging level data (optional) */
+	unsigned char sb_len_wr;		/* [o] byte count actually written to sbp */
+	unsigned short host_status;	/* [o] errors from host adapter */
+	unsigned short driver_status;	/* [o] errors from software driver */
+	compat_int_t resid;		/* [o] dxfer_len - actual_transferred */
+	compat_uint_t duration;		/* [o] time taken by cmd (unit: millisec) */
+	compat_uint_t info;		/* [o] auxiliary information */
+} sg_io_hdr32_t;  /* 64 bytes long (on sparc32) */
+
+typedef struct sg_iovec32 {
+	compat_uint_t iov_base;
+	compat_uint_t iov_len;
+} sg_iovec32_t;
+
+static int sg_build_iovec(sg_io_hdr_t __user *sgio, void __user *dxferp, u16 iovec_count)
+{
+	sg_iovec_t __user *iov = (sg_iovec_t __user *) (sgio + 1);
+	sg_iovec32_t __user *iov32 = dxferp;
+	int i;
+
+	for (i = 0; i < iovec_count; i++) {
+		u32 base, len;
+
+		if (get_user(base, &iov32[i].iov_base) ||
+		    get_user(len, &iov32[i].iov_len) ||
+		    put_user(compat_ptr(base), &iov[i].iov_base) ||
+		    put_user(len, &iov[i].iov_len))
+			return -EFAULT;
+	}
+
+	if (put_user(iov, &sgio->dxferp))
+		return -EFAULT;
+	return 0;
+}
+
+int nvme_sg_io32(struct nvme_ns *ns, unsigned long arg)
+{
+	sg_io_hdr32_t __user *sgio32 = (sg_io_hdr32_t __user *)arg;
+	sg_io_hdr_t __user *sgio;
+	u16 iovec_count;
+	u32 data;
+	void __user *dxferp;
+	int err;
+	int interface_id;
+
+	if (get_user(interface_id, &sgio32->interface_id))
+		return -EFAULT;
+	if (interface_id != 'S')
+		return -EINVAL;
+
+	if (get_user(iovec_count, &sgio32->iovec_count))
+		return -EFAULT;
+
+	{
+		void __user *top = compat_alloc_user_space(0);
+		void __user *new = compat_alloc_user_space(sizeof(sg_io_hdr_t) +
+				       (iovec_count * sizeof(sg_iovec_t)));
+		if (new > top)
+			return -EINVAL;
+
+		sgio = new;
+	}
+
+	/* Ok, now construct.  */
+	if (copy_in_user(&sgio->interface_id, &sgio32->interface_id,
+			 (2 * sizeof(int)) +
+			 (2 * sizeof(unsigned char)) +
+			 (1 * sizeof(unsigned short)) +
+			 (1 * sizeof(unsigned int))))
+		return -EFAULT;
+
+	if (get_user(data, &sgio32->dxferp))
+		return -EFAULT;
+	dxferp = compat_ptr(data);
+	if (iovec_count) {
+		if (sg_build_iovec(sgio, dxferp, iovec_count))
+			return -EFAULT;
+	} else {
+		if (put_user(dxferp, &sgio->dxferp))
+			return -EFAULT;
+	}
+
+	{
+		unsigned char __user *cmdp;
+		unsigned char __user *sbp;
+
+		if (get_user(data, &sgio32->cmdp))
+			return -EFAULT;
+		cmdp = compat_ptr(data);
+
+		if (get_user(data, &sgio32->sbp))
+			return -EFAULT;
+		sbp = compat_ptr(data);
+
+		if (put_user(cmdp, &sgio->cmdp) ||
+		    put_user(sbp, &sgio->sbp))
+			return -EFAULT;
+	}
+
+	if (copy_in_user(&sgio->timeout, &sgio32->timeout,
+			 3 * sizeof(int)))
+		return -EFAULT;
+
+	if (get_user(data, &sgio32->usr_ptr))
+		return -EFAULT;
+	if (put_user(compat_ptr(data), &sgio->usr_ptr))
+		return -EFAULT;
+
+	err = nvme_sg_io(ns, sgio);
+	if (err >= 0) {
+		void __user *datap;
+
+		if (copy_in_user(&sgio32->pack_id, &sgio->pack_id,
+				 sizeof(int)) ||
+		    get_user(datap, &sgio->usr_ptr) ||
+		    put_user((u32)(unsigned long)datap,
+			     &sgio32->usr_ptr) ||
+		    copy_in_user(&sgio32->status, &sgio->status,
+				 (4 * sizeof(unsigned char)) +
+				 (2 * sizeof(unsigned short)) +
+				 (3 * sizeof(int))))
+			err = -EFAULT;
+	}
+
+	return err;
+}
+
 int nvme_sg_get_version_num(int __user *ip)
 {
 	return put_user(sg_version_num, ip);
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 26ebcf4..6867de6 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -165,6 +165,7 @@ int nvme_set_features(struct nvme_dev *dev, unsigned fid, unsigned dword11,
 struct sg_io_hdr;
 
 int nvme_sg_io(struct nvme_ns *ns, struct sg_io_hdr __user *u_hdr);
+int nvme_sg_io32(struct nvme_ns *ns, unsigned long arg);
 int nvme_sg_get_version_num(int __user *ip);
 
 #endif /* _LINUX_NVME_H */
-- 
1.7.10.4