NVMe: compat SG_IO ioctl

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@intel.com>
Reviewed-by: Vishal Verma <vishal.l.verma@linux.intel.com>
[fixed up CONFIG_COMPAT=n build problems]
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 147 insertions, 0 deletions

diff --git a/drivers/block/nvme-scsi.c b/drivers/block/nvme-scsi.c
index 4a4ff4eb8e23..4a0ceb64e269 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>
@@ -3038,6 +3039,152 @@ int nvme_sg_io(struct nvme_ns *ns, struct sg_io_hdr __user *u_hdr)
         return retcode;
 }
 
+#ifdef CONFIG_COMPAT
+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;
+}
+#endif
+
 int nvme_sg_get_version_num(int __user *ip)
 {
         return put_user(sg_version_num, ip);