nvme: Add compat_ioctl handler for NVME_IOCTL_SUBMIT_IO

Currently 32 bit application gets ENOTTY when it calls
compat_ioctl with NVME_IOCTL_SUBMIT_IO in 64 bit kernel.

The cause is that the results of sizeof(struct nvme_user_io),
which is used to define NVME_IOCTL_SUBMIT_IO,
are not same between 32 bit compiler and 64 bit compiler.

* 32 bit: the result of sizeof nvme_user_io is 44.
* 64 bit: the result of sizeof nvme_user_io is 48.

64 bit compiler seems to add 32 bit padding for multiple of 8 bytes.

This patch adds a compat_ioctl handler.
The handler replaces NVME_IOCTL_SUBMIT_IO32 with NVME_IOCTL_SUBMIT_IO
in case 32 bit application calls compat_ioctl for submit in 64 bit kernel.
Then, it calls nvme_ioctl as usual.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Masahiro Yamada (KIOXIA) <masahiro31.yamada@kioxia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index fde4b3a..3c1c826 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1585,6 +1585,47 @@ static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
        return ret;
 }
 
+#ifdef CONFIG_COMPAT
+struct nvme_user_io32 {
+       __u8    opcode;
+       __u8    flags;
+       __u16   control;
+       __u16   nblocks;
+       __u16   rsvd;
+       __u64   metadata;
+       __u64   addr;
+       __u64   slba;
+       __u32   dsmgmt;
+       __u32   reftag;
+       __u16   apptag;
+       __u16   appmask;
+} __attribute__((__packed__));
+
+#define NVME_IOCTL_SUBMIT_IO32 _IOW('N', 0x42, struct nvme_user_io32)
+
+static int nvme_compat_ioctl(struct block_device *bdev, fmode_t mode,
+               unsigned int cmd, unsigned long arg)
+{
+       /*
+        * Corresponds to the difference of NVME_IOCTL_SUBMIT_IO
+        * between 32 bit programs and 64 bit kernel.
+        * The cause is that the results of sizeof(struct nvme_user_io),
+        * which is used to define NVME_IOCTL_SUBMIT_IO,
+        * are not same between 32 bit compiler and 64 bit compiler.
+        * NVME_IOCTL_SUBMIT_IO32 is for 64 bit kernel handling
+        * NVME_IOCTL_SUBMIT_IO issued from 32 bit programs.
+        * Other IOCTL numbers are same between 32 bit and 64 bit.
+        * So there is nothing to do regarding to other IOCTL numbers.
+        */
+       if (cmd == NVME_IOCTL_SUBMIT_IO32)
+               return nvme_ioctl(bdev, mode, NVME_IOCTL_SUBMIT_IO, arg);
+
+       return nvme_ioctl(bdev, mode, cmd, arg);
+}
+#else
+#define nvme_compat_ioctl      NULL
+#endif /* CONFIG_COMPAT */
+
 static int nvme_open(struct block_device *bdev, fmode_t mode)
 {
        struct nvme_ns *ns = bdev->bd_disk->private_data;
@@ -2028,7 +2069,7 @@ EXPORT_SYMBOL_GPL(nvme_sec_submit);
 static const struct block_device_operations nvme_fops = {
        .owner          = THIS_MODULE,
        .ioctl          = nvme_ioctl,
-       .compat_ioctl   = nvme_ioctl,
+       .compat_ioctl   = nvme_compat_ioctl,
        .open           = nvme_open,
        .release        = nvme_release,
        .getgeo         = nvme_getgeo,
@@ -2056,7 +2097,7 @@ const struct block_device_operations nvme_ns_head_ops = {
        .open           = nvme_ns_head_open,
        .release        = nvme_ns_head_release,
        .ioctl          = nvme_ioctl,
-       .compat_ioctl   = nvme_ioctl,
+       .compat_ioctl   = nvme_compat_ioctl,
        .getgeo         = nvme_getgeo,
        .pr_ops         = &nvme_pr_ops,
 };