scsi: cxlflash: Introduce host ioctl support
As staging for supporting various host management functions, add a host
ioctl infrastructure to filter ioctl commands and perform operations that
are common for all host ioctls. Also update the cxlflash documentation to
create a new section for documenting host ioctls.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 7732dfc..be468ed1 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -2693,7 +2693,14 @@ static ssize_t lun_mode_store(struct device *dev,
static ssize_t ioctl_version_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- return scnprintf(buf, PAGE_SIZE, "%u\n", DK_CXLFLASH_VERSION_0);
+ ssize_t bytes = 0;
+
+ bytes = scnprintf(buf, PAGE_SIZE,
+ "disk: %u\n", DK_CXLFLASH_VERSION_0);
+ bytes += scnprintf(buf + bytes, PAGE_SIZE - bytes,
+ "host: %u\n", HT_CXLFLASH_VERSION_0);
+
+ return bytes;
}
/**
@@ -3211,12 +3218,124 @@ static int cxlflash_chr_open(struct inode *inode, struct file *file)
return 0;
}
+/**
+ * decode_hioctl() - translates encoded host ioctl to easily identifiable string
+ * @cmd: The host ioctl command to decode.
+ *
+ * Return: A string identifying the decoded host ioctl.
+ */
+static char *decode_hioctl(int cmd)
+{
+ switch (cmd) {
+ default:
+ return "UNKNOWN";
+ }
+
+ return "UNKNOWN";
+}
+
+/**
+ * cxlflash_chr_ioctl() - character device IOCTL handler
+ * @file: File pointer for this device.
+ * @cmd: IOCTL command.
+ * @arg: Userspace ioctl data structure.
+ *
+ * A read/write semaphore is used to implement a 'drain' of currently
+ * running ioctls. The read semaphore is taken at the beginning of each
+ * ioctl thread and released upon concluding execution. Additionally the
+ * semaphore should be released and then reacquired in any ioctl execution
+ * path which will wait for an event to occur that is outside the scope of
+ * the ioctl (i.e. an adapter reset). To drain the ioctls currently running,
+ * a thread simply needs to acquire the write semaphore.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static long cxlflash_chr_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ typedef int (*hioctl) (struct cxlflash_cfg *, void *);
+
+ struct cxlflash_cfg *cfg = file->private_data;
+ struct device *dev = &cfg->dev->dev;
+ char buf[sizeof(union cxlflash_ht_ioctls)];
+ void __user *uarg = (void __user *)arg;
+ struct ht_cxlflash_hdr *hdr;
+ size_t size = 0;
+ bool known_ioctl = false;
+ int idx = 0;
+ int rc = 0;
+ hioctl do_ioctl = NULL;
+
+ static const struct {
+ size_t size;
+ hioctl ioctl;
+ } ioctl_tbl[] = { /* NOTE: order matters here */
+ };
+
+ /* Hold read semaphore so we can drain if needed */
+ down_read(&cfg->ioctl_rwsem);
+
+ dev_dbg(dev, "%s: cmd=%u idx=%d tbl_size=%lu\n",
+ __func__, cmd, idx, sizeof(ioctl_tbl));
+
+ switch (cmd) {
+ default:
+ rc = -EINVAL;
+ goto out;
+ }
+
+ if (unlikely(copy_from_user(&buf, uarg, size))) {
+ dev_err(dev, "%s: copy_from_user() fail "
+ "size=%lu cmd=%d (%s) uarg=%p\n",
+ __func__, size, cmd, decode_hioctl(cmd), uarg);
+ rc = -EFAULT;
+ goto out;
+ }
+
+ hdr = (struct ht_cxlflash_hdr *)&buf;
+ if (hdr->version != HT_CXLFLASH_VERSION_0) {
+ dev_dbg(dev, "%s: Version %u not supported for %s\n",
+ __func__, hdr->version, decode_hioctl(cmd));
+ rc = -EINVAL;
+ goto out;
+ }
+
+ if (hdr->rsvd[0] || hdr->rsvd[1] || hdr->return_flags) {
+ dev_dbg(dev, "%s: Reserved/rflags populated\n", __func__);
+ rc = -EINVAL;
+ goto out;
+ }
+
+ rc = do_ioctl(cfg, (void *)&buf);
+ if (likely(!rc))
+ if (unlikely(copy_to_user(uarg, &buf, size))) {
+ dev_err(dev, "%s: copy_to_user() fail "
+ "size=%lu cmd=%d (%s) uarg=%p\n",
+ __func__, size, cmd, decode_hioctl(cmd), uarg);
+ rc = -EFAULT;
+ }
+
+ /* fall through to exit */
+
+out:
+ up_read(&cfg->ioctl_rwsem);
+ if (unlikely(rc && known_ioctl))
+ dev_err(dev, "%s: ioctl %s (%08X) returned rc=%d\n",
+ __func__, decode_hioctl(cmd), cmd, rc);
+ else
+ dev_dbg(dev, "%s: ioctl %s (%08X) returned rc=%d\n",
+ __func__, decode_hioctl(cmd), cmd, rc);
+ return rc;
+}
+
/*
* Character device file operations
*/
static const struct file_operations cxlflash_chr_fops = {
.owner = THIS_MODULE,
.open = cxlflash_chr_open,
+ .unlocked_ioctl = cxlflash_chr_ioctl,
+ .compat_ioctl = cxlflash_chr_ioctl,
};
/**