From: "Matthew R. Ochs" <mro...@linux.vnet.ibm.com> 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 <mro...@linux.vnet.ibm.com> Signed-off-by: Uma Krishnan <ukri...@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 08244be..6b6cc4c 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -324,7 +324,7 @@ Code Seq#(hex) Include File Comments 0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remotep...@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.kl...@puffin.lb.shuttle.de> 0xCD 01 linux/reiserfs_fs.h diff --git a/Documentation/powerpc/cxlflash.txt b/Documentation/powerpc/cxlflash.txt index f9036cb..ee67021 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 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, }; /** diff --git a/include/uapi/scsi/cxlflash_ioctl.h b/include/uapi/scsi/cxlflash_ioctl.h index e9fdc12..87e1f63 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 */ -- 2.1.0
