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344 lines
8 KiB
C
344 lines
8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* HMC Drive FTP Services
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*
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* Copyright IBM Corp. 2013
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* Author(s): Ralf Hoppe (rhoppe@de.ibm.com)
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*/
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#define KMSG_COMPONENT "hmcdrv"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/export.h>
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#include <linux/ctype.h>
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#include <linux/crc16.h>
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#include "hmcdrv_ftp.h"
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#include "hmcdrv_cache.h"
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#include "sclp_ftp.h"
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#include "diag_ftp.h"
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/**
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* struct hmcdrv_ftp_ops - HMC drive FTP operations
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* @startup: startup function
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* @shutdown: shutdown function
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* @transfer: FTP transfer function
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*/
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struct hmcdrv_ftp_ops {
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int (*startup)(void);
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void (*shutdown)(void);
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ssize_t (*transfer)(const struct hmcdrv_ftp_cmdspec *ftp,
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size_t *fsize);
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};
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static enum hmcdrv_ftp_cmdid hmcdrv_ftp_cmd_getid(const char *cmd, int len);
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static int hmcdrv_ftp_parse(char *cmd, struct hmcdrv_ftp_cmdspec *ftp);
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static const struct hmcdrv_ftp_ops *hmcdrv_ftp_funcs; /* current operations */
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static DEFINE_MUTEX(hmcdrv_ftp_mutex); /* mutex for hmcdrv_ftp_funcs */
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static unsigned hmcdrv_ftp_refcnt; /* start/shutdown reference counter */
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/**
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* hmcdrv_ftp_cmd_getid() - determine FTP command ID from a command string
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* @cmd: FTP command string (NOT zero-terminated)
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* @len: length of FTP command string in @cmd
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*/
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static enum hmcdrv_ftp_cmdid hmcdrv_ftp_cmd_getid(const char *cmd, int len)
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{
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/* HMC FTP command descriptor */
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struct hmcdrv_ftp_cmd_desc {
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const char *str; /* command string */
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enum hmcdrv_ftp_cmdid cmd; /* associated command as enum */
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};
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/* Description of all HMC drive FTP commands
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*
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* Notes:
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* 1. Array size should be a prime number.
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* 2. Do not change the order of commands in table (because the
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* index is determined by CRC % ARRAY_SIZE).
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* 3. Original command 'nlist' was renamed, else the CRC would
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* collide with 'append' (see point 2).
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*/
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static const struct hmcdrv_ftp_cmd_desc ftpcmds[7] = {
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{.str = "get", /* [0] get (CRC = 0x68eb) */
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.cmd = HMCDRV_FTP_GET},
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{.str = "dir", /* [1] dir (CRC = 0x6a9e) */
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.cmd = HMCDRV_FTP_DIR},
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{.str = "delete", /* [2] delete (CRC = 0x53ae) */
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.cmd = HMCDRV_FTP_DELETE},
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{.str = "nls", /* [3] nls (CRC = 0xf87c) */
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.cmd = HMCDRV_FTP_NLIST},
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{.str = "put", /* [4] put (CRC = 0xac56) */
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.cmd = HMCDRV_FTP_PUT},
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{.str = "append", /* [5] append (CRC = 0xf56e) */
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.cmd = HMCDRV_FTP_APPEND},
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{.str = NULL} /* [6] unused */
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};
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const struct hmcdrv_ftp_cmd_desc *pdesc;
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u16 crc = 0xffffU;
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if (len == 0)
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return HMCDRV_FTP_NOOP; /* error indiactor */
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crc = crc16(crc, cmd, len);
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pdesc = ftpcmds + (crc % ARRAY_SIZE(ftpcmds));
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pr_debug("FTP command '%s' has CRC 0x%04x, at table pos. %lu\n",
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cmd, crc, (crc % ARRAY_SIZE(ftpcmds)));
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if (!pdesc->str || strncmp(pdesc->str, cmd, len))
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return HMCDRV_FTP_NOOP;
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pr_debug("FTP command '%s' found, with ID %d\n",
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pdesc->str, pdesc->cmd);
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return pdesc->cmd;
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}
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/**
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* hmcdrv_ftp_parse() - HMC drive FTP command parser
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* @cmd: FTP command string "<cmd> <filename>"
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* @ftp: Pointer to FTP command specification buffer (output)
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*
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* Return: 0 on success, else a (negative) error code
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*/
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static int hmcdrv_ftp_parse(char *cmd, struct hmcdrv_ftp_cmdspec *ftp)
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{
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char *start;
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int argc = 0;
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ftp->id = HMCDRV_FTP_NOOP;
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ftp->fname = NULL;
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while (*cmd != '\0') {
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while (isspace(*cmd))
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++cmd;
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if (*cmd == '\0')
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break;
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start = cmd;
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switch (argc) {
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case 0: /* 1st argument (FTP command) */
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while ((*cmd != '\0') && !isspace(*cmd))
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++cmd;
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ftp->id = hmcdrv_ftp_cmd_getid(start, cmd - start);
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break;
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case 1: /* 2nd / last argument (rest of line) */
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while ((*cmd != '\0') && !iscntrl(*cmd))
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++cmd;
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ftp->fname = start;
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fallthrough;
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default:
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*cmd = '\0';
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break;
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} /* switch */
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++argc;
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} /* while */
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if (!ftp->fname || (ftp->id == HMCDRV_FTP_NOOP))
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return -EINVAL;
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return 0;
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}
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/**
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* hmcdrv_ftp_do() - perform a HMC drive FTP, with data from kernel-space
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* @ftp: pointer to FTP command specification
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*
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* Return: number of bytes read/written or a negative error code
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*/
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ssize_t hmcdrv_ftp_do(const struct hmcdrv_ftp_cmdspec *ftp)
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{
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ssize_t len;
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mutex_lock(&hmcdrv_ftp_mutex);
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if (hmcdrv_ftp_funcs && hmcdrv_ftp_refcnt) {
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pr_debug("starting transfer, cmd %d for '%s' at %lld with %zd bytes\n",
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ftp->id, ftp->fname, (long long) ftp->ofs, ftp->len);
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len = hmcdrv_cache_cmd(ftp, hmcdrv_ftp_funcs->transfer);
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} else {
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len = -ENXIO;
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}
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mutex_unlock(&hmcdrv_ftp_mutex);
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return len;
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}
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EXPORT_SYMBOL(hmcdrv_ftp_do);
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/**
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* hmcdrv_ftp_probe() - probe for the HMC drive FTP service
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*
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* Return: 0 if service is available, else an (negative) error code
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*/
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int hmcdrv_ftp_probe(void)
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{
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int rc;
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struct hmcdrv_ftp_cmdspec ftp = {
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.id = HMCDRV_FTP_NOOP,
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.ofs = 0,
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.fname = "",
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.len = PAGE_SIZE
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};
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ftp.buf = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
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if (!ftp.buf)
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return -ENOMEM;
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rc = hmcdrv_ftp_startup();
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if (rc)
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goto out;
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rc = hmcdrv_ftp_do(&ftp);
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hmcdrv_ftp_shutdown();
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switch (rc) {
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case -ENOENT: /* no such file/media or currently busy, */
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case -EBUSY: /* but service seems to be available */
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rc = 0;
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break;
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default: /* leave 'rc' as it is for [0, -EPERM, -E...] */
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if (rc > 0)
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rc = 0; /* clear length (success) */
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break;
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} /* switch */
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out:
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free_page((unsigned long) ftp.buf);
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return rc;
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}
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EXPORT_SYMBOL(hmcdrv_ftp_probe);
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/**
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* hmcdrv_ftp_cmd() - Perform a HMC drive FTP, with data from user-space
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*
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* @cmd: FTP command string "<cmd> <filename>"
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* @offset: file position to read/write
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* @buf: user-space buffer for read/written directory/file
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* @len: size of @buf (read/dir) or number of bytes to write
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*
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* This function must not be called before hmcdrv_ftp_startup() was called.
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*
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* Return: number of bytes read/written or a negative error code
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*/
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ssize_t hmcdrv_ftp_cmd(char __kernel *cmd, loff_t offset,
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char __user *buf, size_t len)
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{
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int order;
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struct hmcdrv_ftp_cmdspec ftp = {.len = len, .ofs = offset};
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ssize_t retlen = hmcdrv_ftp_parse(cmd, &ftp);
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if (retlen)
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return retlen;
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order = get_order(ftp.len);
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ftp.buf = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, order);
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if (!ftp.buf)
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return -ENOMEM;
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switch (ftp.id) {
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case HMCDRV_FTP_DIR:
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case HMCDRV_FTP_NLIST:
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case HMCDRV_FTP_GET:
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retlen = hmcdrv_ftp_do(&ftp);
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if ((retlen >= 0) &&
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copy_to_user(buf, ftp.buf, retlen))
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retlen = -EFAULT;
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break;
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case HMCDRV_FTP_PUT:
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case HMCDRV_FTP_APPEND:
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if (!copy_from_user(ftp.buf, buf, ftp.len))
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retlen = hmcdrv_ftp_do(&ftp);
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else
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retlen = -EFAULT;
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break;
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case HMCDRV_FTP_DELETE:
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retlen = hmcdrv_ftp_do(&ftp);
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break;
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default:
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retlen = -EOPNOTSUPP;
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break;
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}
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free_pages((unsigned long) ftp.buf, order);
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return retlen;
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}
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/**
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* hmcdrv_ftp_startup() - startup of HMC drive FTP functionality for a
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* dedicated (owner) instance
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*
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* Return: 0 on success, else an (negative) error code
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*/
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int hmcdrv_ftp_startup(void)
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{
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static const struct hmcdrv_ftp_ops hmcdrv_ftp_zvm = {
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.startup = diag_ftp_startup,
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.shutdown = diag_ftp_shutdown,
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.transfer = diag_ftp_cmd
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};
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static const struct hmcdrv_ftp_ops hmcdrv_ftp_lpar = {
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.startup = sclp_ftp_startup,
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.shutdown = sclp_ftp_shutdown,
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.transfer = sclp_ftp_cmd
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};
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int rc = 0;
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mutex_lock(&hmcdrv_ftp_mutex); /* block transfers while start-up */
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if (hmcdrv_ftp_refcnt == 0) {
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if (MACHINE_IS_VM)
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hmcdrv_ftp_funcs = &hmcdrv_ftp_zvm;
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else if (MACHINE_IS_LPAR || MACHINE_IS_KVM)
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hmcdrv_ftp_funcs = &hmcdrv_ftp_lpar;
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else
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rc = -EOPNOTSUPP;
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if (hmcdrv_ftp_funcs)
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rc = hmcdrv_ftp_funcs->startup();
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}
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if (!rc)
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++hmcdrv_ftp_refcnt;
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mutex_unlock(&hmcdrv_ftp_mutex);
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return rc;
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}
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EXPORT_SYMBOL(hmcdrv_ftp_startup);
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/**
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* hmcdrv_ftp_shutdown() - shutdown of HMC drive FTP functionality for a
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* dedicated (owner) instance
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*/
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void hmcdrv_ftp_shutdown(void)
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{
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mutex_lock(&hmcdrv_ftp_mutex);
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--hmcdrv_ftp_refcnt;
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if ((hmcdrv_ftp_refcnt == 0) && hmcdrv_ftp_funcs)
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hmcdrv_ftp_funcs->shutdown();
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mutex_unlock(&hmcdrv_ftp_mutex);
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}
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EXPORT_SYMBOL(hmcdrv_ftp_shutdown);
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