[PATCH] sd.c

The below does two things:
(i) do not try to spin up a CF reader without media
(ii) be careful when asking for the cache parameters mode page

[do not ask for this page when no media are present:
it is meaningless, and some devices react badly if we do;
check the reply so that we do not read past the end of the reply;
first give a small transport length - some USB devices are unhappy
if we ask for more than they provide]

Andries

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 2ce2cb32ee76a522347465ac25f14815b0d01f9d..13aa0d8b8280bc2430e47366c640139d7d6ab625 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -79,7 +79,7 @@ struct scsi_disk {
        u8              media_present;
        u8              write_prot;
        unsigned        WCE : 1;        /* state of disk WCE bit */
-       unsigned        RCD : 1;        /* state of disk RCD bit */
+       unsigned        RCD : 1;        /* state of disk RCD bit, unused */
 };
 
 static LIST_HEAD(sd_devlist);
@@ -217,7 +217,7 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
        block = SCpnt->request->sector;
        this_count = SCpnt->request_bufflen >> 9;
 
-       SCSI_LOG_HLQUEUE(1, printk("sd_command_init: disk=%s, block=%llu, "
+       SCSI_LOG_HLQUEUE(1, printk("sd_init_command: disk=%s, block=%llu, "
                            "count=%d\n", disk->disk_name, (unsigned long long)block, this_count));
 
        if (!sdp || !sdp->online ||
@@ -809,9 +809,22 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
                if (media_not_present(sdkp, SRpnt))
                        return;
 
-               /* Look for devices that return NOT_READY.
-                * Issue command to spin up drive for these cases. */
-               if (the_result && SRpnt->sr_sense_buffer[2] == NOT_READY) {
+               if (the_result == 0)
+                       break;          /* all is well now */
+
+               /*
+                * If manual intervention is required, or this is an
+                * absent USB storage device, a spinup is meaningless.
+                */
+               if (SRpnt->sr_sense_buffer[2] == NOT_READY &&
+                   SRpnt->sr_sense_buffer[12] == 4 /* not ready */ &&
+                   SRpnt->sr_sense_buffer[13] == 3)
+                       break;          /* manual intervention required */
+
+               /*
+                * Issue command to spin up drive when not ready
+                */
+               if (SRpnt->sr_sense_buffer[2] == NOT_READY) {
                        unsigned long time1;
                        if (!spintime) {
                                printk(KERN_NOTICE "%s: Spinning up disk...",
@@ -839,7 +852,7 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
                        } while(time1);
                        printk(".");
                }
-       } while (the_result && spintime &&
+       } while (spintime &&
                 time_after(spintime_value + 100 * HZ, jiffies));
 
        if (spintime) {
@@ -850,80 +863,6 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
        }
 }
 
-/*
- * sd_read_cache_type - called only from sd_init_onedisk()
- */
-static void
-sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
-                  struct scsi_request *SRpnt, unsigned char *buffer) {
-
-       unsigned char cmd[10];
-       int the_result, retries;
-
-       retries = 3;
-       do {
-
-               memset((void *) &cmd[0], 0, 10);
-               cmd[0] = MODE_SENSE;
-               cmd[1] = 0x08;  /* DBD */
-               cmd[2] = 0x08;  /* current values, cache page */
-               cmd[4] = 128;   /* allocation length */
-
-
-               memset((void *) buffer, 0, 24);
-               SRpnt->sr_cmd_len = 0;
-               SRpnt->sr_sense_buffer[0] = 0;
-               SRpnt->sr_sense_buffer[2] = 0;
-
-               SRpnt->sr_data_direction = SCSI_DATA_READ;
-               scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
-                           128, SD_TIMEOUT, SD_MAX_RETRIES);
-
-               the_result = SRpnt->sr_result;
-               retries--;
-
-       } while (the_result && retries);
-
-       if (the_result) {
-               if(status_byte(the_result) == CHECK_CONDITION
-                  && (SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
-                  && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
-                  /* The next are ASC 0x24 ASCQ 0x00: Invalid field in CDB */
-                  && SRpnt->sr_sense_buffer[12] == 0x24
-                  && SRpnt->sr_sense_buffer[13] == 0x00) {
-                       printk(KERN_NOTICE "SCSI device %s: cache data unavailable\n", diskname);
-               } else {
-                       printk(KERN_ERR "%s : MODE SENSE failed.\n"
-                              "%s : status = %x, message = %02x, host = %d, driver = %02x \n",
-                              diskname, diskname,
-                              status_byte(the_result),
-                              msg_byte(the_result),
-                              host_byte(the_result),
-                              driver_byte(the_result)
-                              );
-                       if (driver_byte(the_result) & DRIVER_SENSE)
-                               print_req_sense("sd", SRpnt);
-                       else
-                               printk(KERN_ERR "%s : sense not available. \n", diskname);
-                       
-                       printk(KERN_ERR "%s : assuming drive cache: write through\n", diskname);
-               }
-               sdkp->WCE = 0;
-               sdkp->RCD = 0;
-       } else {
-               const char *types[] = { "write through", "none", "write back", "write back, no read (daft)" };
-               int ct = 0;
-               int offset = buffer[3] + 4; /* offset to start of mode page */
-
-               sdkp->WCE = (buffer[offset + 2] & 0x04) == 0x04;
-               sdkp->RCD = (buffer[offset + 2] & 0x01) == 0x01;
-
-               ct =  sdkp->RCD + 2*sdkp->WCE;
-
-               printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n", diskname, types[ct]);
-       }
-}
-
 /*
  * read disk capacity - called only in sd_init_onedisk()
  */
@@ -1102,11 +1041,12 @@ got_data:
 
 static int
 sd_do_mode_sense6(struct scsi_device *sdp, struct scsi_request *SRpnt,
-                 int modepage, unsigned char *buffer, int len) {
+                 int dbd, int modepage, unsigned char *buffer, int len) {
        unsigned char cmd[8];
 
        memset((void *) &cmd[0], 0, 8);
        cmd[0] = MODE_SENSE;
+       cmd[1] = dbd;
        cmd[2] = modepage;
        cmd[4] = len;
 
@@ -1115,6 +1055,8 @@ sd_do_mode_sense6(struct scsi_device *sdp, struct scsi_request *SRpnt,
        SRpnt->sr_sense_buffer[2] = 0;
        SRpnt->sr_data_direction = SCSI_DATA_READ;
 
+       memset((void *) buffer, 0, len);
+
        scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
                      len, SD_TIMEOUT, SD_MAX_RETRIES);
 
@@ -1135,7 +1077,7 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
         * We have to start carefully: some devices hang if we ask
         * for more than is available.
         */
-       res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 4);
+       res = sd_do_mode_sense6(sdp, SRpnt, 0, 0x3F, buffer, 4);
 
        /*
         * Second attempt: ask for page 0
@@ -1143,13 +1085,13 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
         * Sense Key 5: Illegal Request, Sense Code 24: Invalid field in CDB.
         */
        if (res)
-               res = sd_do_mode_sense6(sdp, SRpnt, 0, buffer, 4);
+               res = sd_do_mode_sense6(sdp, SRpnt, 0, 0, buffer, 4);
 
        /*
         * Third attempt: ask 255 bytes, as we did earlier.
         */
        if (res)
-               res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 255);
+               res = sd_do_mode_sense6(sdp, SRpnt, 0, 0x3F, buffer, 255);
 
        if (res) {
                printk(KERN_WARNING
@@ -1163,6 +1105,65 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, char *diskname,
        }
 }
 
+/*
+ * sd_read_cache_type - called only from sd_init_onedisk()
+ */
+static void
+sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
+                  struct scsi_request *SRpnt, unsigned char *buffer) {
+       struct scsi_device *sdp = sdkp->device;
+       int len = 0, res;
+
+       const int dbd = 0x08;      /* DBD */
+       const int modepage = 0x08; /* current values, cache page */
+
+       /* cautiously ask */
+       res = sd_do_mode_sense6(sdp, SRpnt, dbd, modepage, buffer, 4);
+
+       if (res == 0) {
+               /* that went OK, now ask for the proper length */
+               len = buffer[0] + 1;
+               if (len > 128)
+                       len = 128;
+               res = sd_do_mode_sense6(sdp, SRpnt, dbd, modepage, buffer, len);
+       }
+
+       if (res == 0 && buffer[3] + 6 < len) {
+               const char *types[] = {
+                       "write through", "none", "write back",
+                       "write back, no read (daft)"
+               };
+               int ct = 0;
+               int offset = buffer[3] + 4; /* start of mode page */
+
+               sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
+               sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);
+
+               ct =  sdkp->RCD + 2*sdkp->WCE;
+
+               printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
+                      diskname, types[ct]);
+       } else {
+               if (res == 0 ||
+                   (status_byte(res) == CHECK_CONDITION
+                    && (SRpnt->sr_sense_buffer[0] & 0x70) == 0x70
+                    && (SRpnt->sr_sense_buffer[2] & 0x0f) == ILLEGAL_REQUEST
+                    /* ASC 0x24 ASCQ 0x00: Invalid field in CDB */
+                    && SRpnt->sr_sense_buffer[12] == 0x24
+                    && SRpnt->sr_sense_buffer[13] == 0x00)) {
+                       printk(KERN_NOTICE "%s: cache data unavailable\n",
+                              diskname);
+               } else {
+                       printk(KERN_ERR "%s: asking for cache data failed\n",
+                              diskname);
+               }
+               printk(KERN_ERR "%s: assuming drive cache: write through\n",
+                      diskname);
+               sdkp->WCE = 0;
+               sdkp->RCD = 0;
+       }
+}
+
 /**
  *     sd_init_onedisk - called the first time a new disk is seen,
  *     performs disk spin up, read_capacity, etc.
@@ -1208,15 +1209,20 @@ sd_init_onedisk(struct scsi_disk * sdkp, struct gendisk *disk)
        sdkp->device->sector_size = 512;
        sdkp->media_present = 1;
        sdkp->write_prot = 0;
+       sdkp->WCE = 0;
+       sdkp->RCD = 0;
 
        sd_spinup_disk(sdkp, disk->disk_name, SRpnt, buffer);
-       sd_read_cache_type(sdkp, disk->disk_name, SRpnt, buffer);
 
        if (sdkp->media_present)
                sd_read_capacity(sdkp, disk->disk_name, SRpnt, buffer);
        
        if (sdp->removable && sdkp->media_present)
                sd_read_write_protect_flag(sdkp, disk->disk_name, SRpnt, buffer);
+       /* without media there is no reason to ask;
+          moreover, some devices react badly if we do */
+       if (sdkp->media_present)
+               sd_read_cache_type(sdkp, disk->disk_name, SRpnt, buffer);
                
        SRpnt->sr_device->ten = 1;
        SRpnt->sr_device->remap = 1;