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![Jayachandran C](/assets/img/avatar_default.png)
This patch attempts to fix an issue found in drivers/scsi/scsi_ioctl.c by Coverity. Error reported: CID: 3437 Checker: FORWARD_NULL (help) File: /export2/p4-coverity/mc2/linux26/drivers/scsi/scsi_ioctl.c Function: scsi_ioctl_send_command Description: Variable "buf" tracked as NULL was passed to a function that dereferences it. Patch description: buf can be NULL if inlen and outlen are both 0. This patch adds check if the length is non-zero before calling copy from/to user. Signed-off-by: Jayachandran C. <c.jayachandran@gmail.com> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
490 lines
13 KiB
C
490 lines
13 KiB
C
/*
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* Changes:
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br> 08/23/2000
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* - get rid of some verify_areas and use __copy*user and __get/put_user
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* for the ones that remain
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*/
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#include <linux/module.h>
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#include <linux/blkdev.h>
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#include <linux/interrupt.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <asm/uaccess.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_eh.h>
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#include <scsi/scsi_host.h>
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#include <scsi/scsi_ioctl.h>
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#include <scsi/scsi_request.h>
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#include <scsi/sg.h>
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#include <scsi/scsi_dbg.h>
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#include "scsi_logging.h"
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#define NORMAL_RETRIES 5
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#define IOCTL_NORMAL_TIMEOUT (10 * HZ)
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#define MAX_BUF PAGE_SIZE
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/**
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* ioctl_probe -- return host identification
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* @host: host to identify
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* @buffer: userspace buffer for identification
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*
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* Return an identifying string at @buffer, if @buffer is non-NULL, filling
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* to the length stored at * (int *) @buffer.
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*/
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static int ioctl_probe(struct Scsi_Host *host, void __user *buffer)
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{
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unsigned int len, slen;
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const char *string;
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if (buffer) {
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if (get_user(len, (unsigned int __user *) buffer))
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return -EFAULT;
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if (host->hostt->info)
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string = host->hostt->info(host);
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else
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string = host->hostt->name;
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if (string) {
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slen = strlen(string);
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if (len > slen)
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len = slen + 1;
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if (copy_to_user(buffer, string, len))
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return -EFAULT;
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}
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}
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return 1;
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}
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/*
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* The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
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* The IOCTL_NORMAL_TIMEOUT and NORMAL_RETRIES variables are used.
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*
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* dev is the SCSI device struct ptr, *(int *) arg is the length of the
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* input data, if any, not including the command string & counts,
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* *((int *)arg + 1) is the output buffer size in bytes.
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*
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* *(char *) ((int *) arg)[2] the actual command byte.
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*
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* Note that if more than MAX_BUF bytes are requested to be transferred,
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* the ioctl will fail with error EINVAL.
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*
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* This size *does not* include the initial lengths that were passed.
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*
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* The SCSI command is read from the memory location immediately after the
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* length words, and the input data is right after the command. The SCSI
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* routines know the command size based on the opcode decode.
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*
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* The output area is then filled in starting from the command byte.
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*/
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static int ioctl_internal_command(struct scsi_device *sdev, char *cmd,
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int timeout, int retries)
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{
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int result;
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struct scsi_sense_hdr sshdr;
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SCSI_LOG_IOCTL(1, printk("Trying ioctl with scsi command %d\n", *cmd));
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result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0,
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&sshdr, timeout, retries);
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SCSI_LOG_IOCTL(2, printk("Ioctl returned 0x%x\n", result));
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if ((driver_byte(result) & DRIVER_SENSE) &&
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(scsi_sense_valid(&sshdr))) {
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switch (sshdr.sense_key) {
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case ILLEGAL_REQUEST:
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if (cmd[0] == ALLOW_MEDIUM_REMOVAL)
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sdev->lockable = 0;
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else
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printk(KERN_INFO "ioctl_internal_command: "
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"ILLEGAL REQUEST asc=0x%x ascq=0x%x\n",
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sshdr.asc, sshdr.ascq);
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break;
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case NOT_READY: /* This happens if there is no disc in drive */
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if (sdev->removable && (cmd[0] != TEST_UNIT_READY)) {
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printk(KERN_INFO "Device not ready. Make sure"
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" there is a disc in the drive.\n");
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break;
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}
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case UNIT_ATTENTION:
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if (sdev->removable) {
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sdev->changed = 1;
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result = 0; /* This is no longer considered an error */
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break;
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}
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default: /* Fall through for non-removable media */
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sdev_printk(KERN_INFO, sdev,
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"ioctl_internal_command return code = %x\n",
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result);
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scsi_print_sense_hdr(" ", &sshdr);
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break;
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}
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}
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SCSI_LOG_IOCTL(2, printk("IOCTL Releasing command\n"));
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return result;
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}
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int scsi_set_medium_removal(struct scsi_device *sdev, char state)
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{
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char scsi_cmd[MAX_COMMAND_SIZE];
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int ret;
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if (!sdev->removable || !sdev->lockable)
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return 0;
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scsi_cmd[0] = ALLOW_MEDIUM_REMOVAL;
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scsi_cmd[1] = 0;
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scsi_cmd[2] = 0;
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scsi_cmd[3] = 0;
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scsi_cmd[4] = state;
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scsi_cmd[5] = 0;
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ret = ioctl_internal_command(sdev, scsi_cmd,
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IOCTL_NORMAL_TIMEOUT, NORMAL_RETRIES);
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if (ret == 0)
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sdev->locked = (state == SCSI_REMOVAL_PREVENT);
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return ret;
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}
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EXPORT_SYMBOL(scsi_set_medium_removal);
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/*
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* This interface is deprecated - users should use the scsi generic (sg)
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* interface instead, as this is a more flexible approach to performing
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* generic SCSI commands on a device.
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*
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* The structure that we are passed should look like:
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*
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* struct sdata {
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* unsigned int inlen; [i] Length of data to be written to device
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* unsigned int outlen; [i] Length of data to be read from device
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* unsigned char cmd[x]; [i] SCSI command (6 <= x <= 12).
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* [o] Data read from device starts here.
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* [o] On error, sense buffer starts here.
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* unsigned char wdata[y]; [i] Data written to device starts here.
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* };
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* Notes:
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* - The SCSI command length is determined by examining the 1st byte
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* of the given command. There is no way to override this.
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* - Data transfers are limited to PAGE_SIZE (4K on i386, 8K on alpha).
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* - The length (x + y) must be at least OMAX_SB_LEN bytes long to
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* accommodate the sense buffer when an error occurs.
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* The sense buffer is truncated to OMAX_SB_LEN (16) bytes so that
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* old code will not be surprised.
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* - If a Unix error occurs (e.g. ENOMEM) then the user will receive
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* a negative return and the Unix error code in 'errno'.
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* If the SCSI command succeeds then 0 is returned.
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* Positive numbers returned are the compacted SCSI error codes (4
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* bytes in one int) where the lowest byte is the SCSI status.
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* See the drivers/scsi/scsi.h file for more information on this.
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*
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*/
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#define OMAX_SB_LEN 16 /* Old sense buffer length */
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int scsi_ioctl_send_command(struct scsi_device *sdev,
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struct scsi_ioctl_command __user *sic)
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{
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char *buf;
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unsigned char cmd[MAX_COMMAND_SIZE];
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unsigned char sense[SCSI_SENSE_BUFFERSIZE];
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char __user *cmd_in;
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unsigned char opcode;
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unsigned int inlen, outlen, cmdlen;
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unsigned int needed, buf_needed;
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int timeout, retries, result;
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int data_direction;
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gfp_t gfp_mask = GFP_KERNEL;
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if (!sic)
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return -EINVAL;
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if (sdev->host->unchecked_isa_dma)
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gfp_mask |= GFP_DMA;
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/*
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* Verify that we can read at least this much.
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*/
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if (!access_ok(VERIFY_READ, sic, sizeof(Scsi_Ioctl_Command)))
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return -EFAULT;
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if(__get_user(inlen, &sic->inlen))
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return -EFAULT;
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if(__get_user(outlen, &sic->outlen))
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return -EFAULT;
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/*
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* We do not transfer more than MAX_BUF with this interface.
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* If the user needs to transfer more data than this, they
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* should use scsi_generics (sg) instead.
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*/
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if (inlen > MAX_BUF)
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return -EINVAL;
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if (outlen > MAX_BUF)
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return -EINVAL;
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cmd_in = sic->data;
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if(get_user(opcode, cmd_in))
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return -EFAULT;
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needed = buf_needed = (inlen > outlen ? inlen : outlen);
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if (buf_needed) {
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buf_needed = (buf_needed + 511) & ~511;
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if (buf_needed > MAX_BUF)
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buf_needed = MAX_BUF;
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buf = kmalloc(buf_needed, gfp_mask);
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if (!buf)
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return -ENOMEM;
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memset(buf, 0, buf_needed);
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if (inlen == 0) {
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data_direction = DMA_FROM_DEVICE;
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} else if (outlen == 0 ) {
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data_direction = DMA_TO_DEVICE;
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} else {
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/*
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* Can this ever happen?
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*/
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data_direction = DMA_BIDIRECTIONAL;
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}
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} else {
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buf = NULL;
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data_direction = DMA_NONE;
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}
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/*
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* Obtain the command from the user's address space.
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*/
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cmdlen = COMMAND_SIZE(opcode);
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result = -EFAULT;
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if (!access_ok(VERIFY_READ, cmd_in, cmdlen + inlen))
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goto error;
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if(__copy_from_user(cmd, cmd_in, cmdlen))
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goto error;
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/*
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* Obtain the data to be sent to the device (if any).
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*/
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if(inlen && copy_from_user(buf, cmd_in + cmdlen, inlen))
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goto error;
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switch (opcode) {
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case SEND_DIAGNOSTIC:
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case FORMAT_UNIT:
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timeout = FORMAT_UNIT_TIMEOUT;
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retries = 1;
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break;
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case START_STOP:
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timeout = START_STOP_TIMEOUT;
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retries = NORMAL_RETRIES;
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break;
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case MOVE_MEDIUM:
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timeout = MOVE_MEDIUM_TIMEOUT;
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retries = NORMAL_RETRIES;
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break;
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case READ_ELEMENT_STATUS:
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timeout = READ_ELEMENT_STATUS_TIMEOUT;
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retries = NORMAL_RETRIES;
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break;
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case READ_DEFECT_DATA:
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timeout = READ_DEFECT_DATA_TIMEOUT;
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retries = 1;
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break;
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default:
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timeout = IOCTL_NORMAL_TIMEOUT;
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retries = NORMAL_RETRIES;
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break;
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}
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result = scsi_execute(sdev, cmd, data_direction, buf, needed,
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sense, timeout, retries, 0);
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/*
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* If there was an error condition, pass the info back to the user.
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*/
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if (result) {
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int sb_len = sizeof(*sense);
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sb_len = (sb_len > OMAX_SB_LEN) ? OMAX_SB_LEN : sb_len;
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if (copy_to_user(cmd_in, sense, sb_len))
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result = -EFAULT;
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} else {
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if (outlen && copy_to_user(cmd_in, buf, outlen))
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result = -EFAULT;
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}
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error:
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kfree(buf);
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return result;
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}
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EXPORT_SYMBOL(scsi_ioctl_send_command);
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/*
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* The scsi_ioctl_get_pci() function places into arg the value
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* pci_dev::slot_name (8 characters) for the PCI device (if any).
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* Returns: 0 on success
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* -ENXIO if there isn't a PCI device pointer
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* (could be because the SCSI driver hasn't been
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* updated yet, or because it isn't a SCSI
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* device)
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* any copy_to_user() error on failure there
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*/
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static int scsi_ioctl_get_pci(struct scsi_device *sdev, void __user *arg)
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{
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struct device *dev = scsi_get_device(sdev->host);
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if (!dev)
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return -ENXIO;
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return copy_to_user(arg, dev->bus_id, sizeof(dev->bus_id))? -EFAULT: 0;
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}
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/*
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* the scsi_ioctl() function differs from most ioctls in that it does
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* not take a major/minor number as the dev field. Rather, it takes
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* a pointer to a scsi_devices[] element, a structure.
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*/
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int scsi_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
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{
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char scsi_cmd[MAX_COMMAND_SIZE];
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/* No idea how this happens.... */
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if (!sdev)
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return -ENXIO;
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/*
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* If we are in the middle of error recovery, don't let anyone
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* else try and use this device. Also, if error recovery fails, it
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* may try and take the device offline, in which case all further
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* access to the device is prohibited.
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*/
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if (!scsi_block_when_processing_errors(sdev))
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return -ENODEV;
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/* Check for deprecated ioctls ... all the ioctls which don't
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* follow the new unique numbering scheme are deprecated */
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switch (cmd) {
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case SCSI_IOCTL_SEND_COMMAND:
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case SCSI_IOCTL_TEST_UNIT_READY:
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case SCSI_IOCTL_BENCHMARK_COMMAND:
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case SCSI_IOCTL_SYNC:
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case SCSI_IOCTL_START_UNIT:
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case SCSI_IOCTL_STOP_UNIT:
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printk(KERN_WARNING "program %s is using a deprecated SCSI "
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"ioctl, please convert it to SG_IO\n", current->comm);
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break;
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default:
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break;
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}
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switch (cmd) {
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case SCSI_IOCTL_GET_IDLUN:
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if (!access_ok(VERIFY_WRITE, arg, sizeof(struct scsi_idlun)))
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return -EFAULT;
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__put_user((sdev->id & 0xff)
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+ ((sdev->lun & 0xff) << 8)
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+ ((sdev->channel & 0xff) << 16)
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+ ((sdev->host->host_no & 0xff) << 24),
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&((struct scsi_idlun __user *)arg)->dev_id);
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__put_user(sdev->host->unique_id,
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&((struct scsi_idlun __user *)arg)->host_unique_id);
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return 0;
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case SCSI_IOCTL_GET_BUS_NUMBER:
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return put_user(sdev->host->host_no, (int __user *)arg);
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case SCSI_IOCTL_PROBE_HOST:
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return ioctl_probe(sdev->host, arg);
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case SCSI_IOCTL_SEND_COMMAND:
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if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
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return -EACCES;
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return scsi_ioctl_send_command(sdev, arg);
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case SCSI_IOCTL_DOORLOCK:
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return scsi_set_medium_removal(sdev, SCSI_REMOVAL_PREVENT);
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case SCSI_IOCTL_DOORUNLOCK:
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return scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW);
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case SCSI_IOCTL_TEST_UNIT_READY:
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return scsi_test_unit_ready(sdev, IOCTL_NORMAL_TIMEOUT,
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NORMAL_RETRIES);
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case SCSI_IOCTL_START_UNIT:
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scsi_cmd[0] = START_STOP;
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scsi_cmd[1] = 0;
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scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
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scsi_cmd[4] = 1;
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return ioctl_internal_command(sdev, scsi_cmd,
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START_STOP_TIMEOUT, NORMAL_RETRIES);
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case SCSI_IOCTL_STOP_UNIT:
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scsi_cmd[0] = START_STOP;
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scsi_cmd[1] = 0;
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scsi_cmd[2] = scsi_cmd[3] = scsi_cmd[5] = 0;
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scsi_cmd[4] = 0;
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return ioctl_internal_command(sdev, scsi_cmd,
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START_STOP_TIMEOUT, NORMAL_RETRIES);
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case SCSI_IOCTL_GET_PCI:
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return scsi_ioctl_get_pci(sdev, arg);
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default:
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if (sdev->host->hostt->ioctl)
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return sdev->host->hostt->ioctl(sdev, cmd, arg);
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}
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return -EINVAL;
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}
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EXPORT_SYMBOL(scsi_ioctl);
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/*
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* the scsi_nonblock_ioctl() function is designed for ioctls which may
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* be executed even if the device is in recovery.
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*/
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int scsi_nonblockable_ioctl(struct scsi_device *sdev, int cmd,
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void __user *arg, struct file *filp)
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{
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int val, result;
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/* The first set of iocts may be executed even if we're doing
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* error processing, as long as the device was opened
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* non-blocking */
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if (filp && filp->f_flags & O_NONBLOCK) {
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if (scsi_host_in_recovery(sdev->host))
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return -ENODEV;
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} else if (!scsi_block_when_processing_errors(sdev))
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return -ENODEV;
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switch (cmd) {
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case SG_SCSI_RESET:
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result = get_user(val, (int __user *)arg);
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if (result)
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return result;
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if (val == SG_SCSI_RESET_NOTHING)
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return 0;
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switch (val) {
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case SG_SCSI_RESET_DEVICE:
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val = SCSI_TRY_RESET_DEVICE;
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break;
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case SG_SCSI_RESET_BUS:
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val = SCSI_TRY_RESET_BUS;
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break;
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case SG_SCSI_RESET_HOST:
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val = SCSI_TRY_RESET_HOST;
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break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
|
|
return -EACCES;
|
|
return (scsi_reset_provider(sdev, val) ==
|
|
SUCCESS) ? 0 : -EIO;
|
|
}
|
|
return -ENODEV;
|
|
}
|
|
EXPORT_SYMBOL(scsi_nonblockable_ioctl);
|