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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>
zero-colors
Matthew R. Ochs 2017-06-21 21:15:42 -05:00 committed by Martin K. Petersen
parent cf24302790
commit d6e32f530d
4 changed files with 168 additions and 5 deletions
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2
Documentation/ioctl/ioctl-number.txt
View File

@ -326,7 +326,7 @@ Code Seq#(hex) Include File Comments
0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@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@puffin.lb.shuttle.de>
0xCD 01 linux/reiserfs_fs.h

19
Documentation/powerpc/cxlflash.txt
View File

@ -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

121
drivers/scsi/cxlflash/main.c
View File

@ -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,
};
/**

31
include/uapi/scsi/cxlflash_ioctl.h
View File

@ -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 */