[Zesty][PATCH 35/44] scsi: cxlflash: Introduce host ioctl support
Victor Aoqui
victora at br.ibm.com
Fri Jul 7 16:05:49 UTC 2017
From: "Matthew R. Ochs" <mrochs at linux.vnet.ibm.com>
BugLink: http://bugs.launchpad.net/bugs/1702521
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 at linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn at linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen at oracle.com>
(cherry picked from commit d6e32f530df9827070c45b55a6c67dfa8562184c)
Signed-off-by: Victor Aoqui <victora at linux.vnet.ibm.com>
---
Documentation/ioctl/ioctl-number.txt | 2 +-
Documentation/powerpc/cxlflash.txt | 19 +++++-
drivers/scsi/cxlflash/main.c | 121 ++++++++++++++++++++++++++++++++++-
include/uapi/scsi/cxlflash_ioctl.h | 31 ++++++++-
4 files changed, 168 insertions(+), 5 deletions(-)
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 81c7f2bb7daf..6678f0e12422 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -323,7 +323,7 @@ Code Seq#(hex) Include File Comments
0xB4 00-0F linux/gpio.h <mailto:linux-gpio at vger.kernel.org>
0xC0 00-0F linux/usb/iowarrior.h
0xCA 00-0F uapi/misc/cxl.h
-0xCA 80-8F uapi/scsi/cxlflash_ioctl.h
+0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
0xCB 00-1F CBM serial IEC bus in development:
<mailto:michael.klein at puffin.lb.shuttle.de>
0xCD 01 linux/reiserfs_fs.h
diff --git a/Documentation/powerpc/cxlflash.txt b/Documentation/powerpc/cxlflash.txt
index f9036cb0170d..ee67021bbfe4 100644
--- a/Documentation/powerpc/cxlflash.txt
+++ b/Documentation/powerpc/cxlflash.txt
@@ -124,8 +124,8 @@ Block library API
http://github.com/open-power/capiflash
-CXL Flash Driver IOCTLs
-=======================
+CXL Flash Driver LUN IOCTLs
+===========================
Users, such as the block library, that wish to interface with a flash
device (LUN) via user space access need to use the services provided
@@ -367,3 +367,18 @@ DK_CXLFLASH_MANAGE_LUN
exclusive user space access (superpipe). In case a LUN is visible
across multiple ports and adapters, this ioctl is used to uniquely
identify each LUN by its World Wide Node Name (WWNN).
+
+
+CXL Flash Driver Host IOCTLs
+============================
+
+ Each host adapter instance that is supported by the cxlflash driver
+ has a special character device associated with it to enable a set of
+ host management function. These character devices are hosted in a
+ class dedicated for cxlflash and can be accessed via /dev/cxlflash/*.
+
+ Applications can be written to perform various functions using the
+ host ioctl APIs below.
+
+ The structure definitions for these IOCTLs are available in:
+ uapi/scsi/cxlflash_ioctl.h
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 7732dfc099c4..be468ed1d884 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,
};
/**
diff --git a/include/uapi/scsi/cxlflash_ioctl.h b/include/uapi/scsi/cxlflash_ioctl.h
index e9fdc12ad984..87e1f63029bf 100644
--- a/include/uapi/scsi/cxlflash_ioctl.h
+++ b/include/uapi/scsi/cxlflash_ioctl.h
@@ -31,7 +31,7 @@ struct dk_cxlflash_hdr {
};
/*
- * Return flag definitions available to all ioctls
+ * Return flag definitions available to all superpipe ioctls
*
* Similar to the input flags, these are grown from the bottom-up with the
* intention that ioctl-specific return flag definitions would grow from the
@@ -180,6 +180,10 @@ union cxlflash_ioctls {
#define CXL_MAGIC 0xCA
#define CXL_IOWR(_n, _s) _IOWR(CXL_MAGIC, _n, struct _s)
+/*
+ * CXL Flash superpipe ioctls start at base of the reserved CXL_MAGIC
+ * region (0x80) and grow upwards.
+ */
#define DK_CXLFLASH_ATTACH CXL_IOWR(0x80, dk_cxlflash_attach)
#define DK_CXLFLASH_USER_DIRECT CXL_IOWR(0x81, dk_cxlflash_udirect)
#define DK_CXLFLASH_RELEASE CXL_IOWR(0x82, dk_cxlflash_release)
@@ -191,4 +195,29 @@ union cxlflash_ioctls {
#define DK_CXLFLASH_VLUN_RESIZE CXL_IOWR(0x88, dk_cxlflash_resize)
#define DK_CXLFLASH_VLUN_CLONE CXL_IOWR(0x89, dk_cxlflash_clone)
+/*
+ * Structure and flag definitions CXL Flash host ioctls
+ */
+
+#define HT_CXLFLASH_VERSION_0 0
+
+struct ht_cxlflash_hdr {
+ __u16 version; /* Version data */
+ __u16 subcmd; /* Sub-command */
+ __u16 rsvd[2]; /* Reserved for future use */
+ __u64 flags; /* Input flags */
+ __u64 return_flags; /* Returned flags */
+};
+
+union cxlflash_ht_ioctls {
+};
+
+#define MAX_HT_CXLFLASH_IOCTL_SZ (sizeof(union cxlflash_ht_ioctls))
+
+/*
+ * CXL Flash host ioctls start at the top of the reserved CXL_MAGIC
+ * region (0xBF) and grow downwards.
+ */
+
+
#endif /* ifndef _CXLFLASH_IOCTL_H */
--
2.11.0
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