scsi: sg: disable SET_FORCE_LOW_DMA

The ioctl SET_FORCE_LOW_DMA has never worked since the initial git
check-in, and the respective setting is nowadays handled correctly. So
disable it entirely.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 29b86505f796d9fa57c19b958c1c7ae4ef31b298..11ca00d8b54cb451bc9771c313bf22e4b83b82e0 100644 (file)
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -149,7 +149,6 @@ typedef struct sg_fd {              /* holds the state of a file descriptor */
        Sg_request *headrp;     /* head of request slist, NULL->empty */
        struct fasync_struct *async_qp; /* used by asynchronous notification */
        Sg_request req_arr[SG_MAX_QUEUE];       /* used as singly-linked list */
-       char low_dma;           /* as in parent but possibly overridden to 1 */
        char force_packid;      /* 1 -> pack_id input to read(), 0 -> ignored */
        char cmd_q;             /* 1 -> allow command queuing, 0 -> don't */
        unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
@@ -885,24 +884,14 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
                                /* strange ..., for backward compatibility */
                return sfp->timeout_user;
        case SG_SET_FORCE_LOW_DMA:
-               result = get_user(val, ip);
-               if (result)
-                       return result;
-               if (val) {
-                       sfp->low_dma = 1;
-                       if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
-                               val = (int) sfp->reserve.bufflen;
-                               sg_remove_scat(sfp, &sfp->reserve);
-                               sg_build_reserve(sfp, val);
-                       }
-               } else {
-                       if (atomic_read(&sdp->detaching))
-                               return -ENODEV;
-                       sfp->low_dma = sdp->device->host->unchecked_isa_dma;
-               }
+               /*
+                * N.B. This ioctl never worked properly, but failed to
+                * return an error value. So returning '0' to keep compability
+                * with legacy applications.
+                */
                return 0;
        case SG_GET_LOW_DMA:
-               return put_user((int) sfp->low_dma, ip);
+               return put_user((int) sdp->device->host->unchecked_isa_dma, ip);
        case SG_GET_SCSI_ID:
                if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
                        return -EFAULT;
@@ -1829,6 +1818,7 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
        int sg_tablesize = sfp->parentdp->sg_tablesize;
        int blk_size = buff_size, order;
        gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
+       struct sg_device *sdp = sfp->parentdp;
 
        if (blk_size < 0)
                return -EFAULT;
@@ -1854,7 +1844,7 @@ sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
                        scatter_elem_sz_prev = num;
        }
 
-       if (sfp->low_dma)
+       if (sdp->device->host->unchecked_isa_dma)
                gfp_mask |= GFP_DMA;
 
        if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
@@ -2140,8 +2130,6 @@ sg_add_sfp(Sg_device * sdp)
        sfp->timeout = SG_DEFAULT_TIMEOUT;
        sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
        sfp->force_packid = SG_DEF_FORCE_PACK_ID;
-       sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
-           sdp->device->host->unchecked_isa_dma : 1;
        sfp->cmd_q = SG_DEF_COMMAND_Q;
        sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
        sfp->parentdp = sdp;
@@ -2611,7 +2599,7 @@ static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
                           jiffies_to_msecs(fp->timeout),
                           fp->reserve.bufflen,
                           (int) fp->reserve.k_use_sg,
-                          (int) fp->low_dma);
+                          (int) sdp->device->host->unchecked_isa_dma);
                seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
                           (int) fp->cmd_q, (int) fp->force_packid,
                           (int) fp->keep_orphan);

diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index 3afec7032448c8927d2cd134111606ee0206ca3d..20bc71c3e0b81acf07af84fea30d6b530427bb70 100644 (file)
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -197,7 +197,6 @@ typedef struct sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
 #define SG_DEFAULT_RETRIES 0
 
 /* Defaults, commented if they differ from original sg driver */
-#define SG_DEF_FORCE_LOW_DMA 0  /* was 1 -> memory below 16MB on i386 */
 #define SG_DEF_FORCE_PACK_ID 0
 #define SG_DEF_KEEP_ORPHAN 0
 #define SG_DEF_RESERVED_SIZE SG_SCATTER_SZ /* load time option */