1 files changed, 61 insertions, 18 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 1c69c14be0cd..953773cb26d9 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2022,16 +2022,26 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 
         int dbd;
         int modepage;
+        int first_len;
         struct scsi_mode_data data;
         struct scsi_sense_hdr sshdr;
         int old_wce = sdkp->WCE;
         int old_rcd = sdkp->RCD;
         int old_dpofua = sdkp->DPOFUA;
 
-        if (sdp->skip_ms_page_8)
-                goto defaults;
-
-        if (sdp->type == TYPE_RBC) {
+        first_len = 4;
+        if (sdp->skip_ms_page_8) {
+                if (sdp->type == TYPE_RBC)
+                        goto defaults;
+                else {
+                        if (sdp->skip_ms_page_3f)
+                                goto defaults;
+                        modepage = 0x3F;
+                        if (sdp->use_192_bytes_for_3f)
+                                first_len = 192;
+                        dbd = 0;
+                }
+        } else if (sdp->type == TYPE_RBC) {
                 modepage = 6;
                 dbd = 8;
         } else {
@@ -2040,13 +2050,15 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
         }
 
         /* cautiously ask */
-        res = sd_do_mode_sense(sdp, dbd, modepage, buffer, 4, &data, &sshdr);
+        res = sd_do_mode_sense(sdp, dbd, modepage, buffer, first_len,
+                        &data, &sshdr);
 
         if (!scsi_status_is_good(res))
                 goto bad_sense;
 
         if (!data.header_length) {
                 modepage = 6;
+                first_len = 0;
                 sd_printk(KERN_ERR, sdkp, "Missing header in MODE_SENSE response\n");
         }
 
@@ -2059,30 +2071,61 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
          */
         if (len < 3)
                 goto bad_sense;
-        if (len > 20)
-                len = 20;
-
-        /* Take headers and block descriptors into account */
-        len += data.header_length + data.block_descriptor_length;
-        if (len > SD_BUF_SIZE)
-                goto bad_sense;
+        else if (len > SD_BUF_SIZE) {
+                sd_printk(KERN_NOTICE, sdkp, "Truncating mode parameter "
+                          "data from %d to %d bytes\n", len, SD_BUF_SIZE);
+                len = SD_BUF_SIZE;
+        }
+        if (modepage == 0x3F && sdp->use_192_bytes_for_3f)
+                len = 192;
 
         /* Get the data */
-        res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
+        if (len > first_len)
+                res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len,
+                                &data, &sshdr);
 
         if (scsi_status_is_good(res)) {
                 int offset = data.header_length + data.block_descriptor_length;
 
-                if (offset >= SD_BUF_SIZE - 2) {
-                        sd_printk(KERN_ERR, sdkp, "Malformed MODE SENSE response\n");
-                        goto defaults;
+                while (offset < len) {
+                        u8 page_code = buffer[offset] & 0x3F;
+                        u8 spf       = buffer[offset] & 0x40;
+
+                        if (page_code == 8 || page_code == 6) {
+                                /* We're interested only in the first 3 bytes.
+                                 */
+                                if (len - offset <= 2) {
+                                        sd_printk(KERN_ERR, sdkp, "Incomplete "
+                                                  "mode parameter data\n");
+                                        goto defaults;
+                                } else {
+                                        modepage = page_code;
+                                        goto Page_found;
+                                }
+                        } else {
+                                /* Go to the next page */
+                                if (spf && len - offset > 3)
+                                        offset += 4 + (buffer[offset+2] << 8) +
+                                                buffer[offset+3];
+                                else if (!spf && len - offset > 1)
+                                        offset += 2 + buffer[offset+1];
+                                else {
+                                        sd_printk(KERN_ERR, sdkp, "Incomplete "
+                                                  "mode parameter data\n");
+                                        goto defaults;
+                                }
+                        }
                 }
 
-                if ((buffer[offset] & 0x3f) != modepage) {
+                if (modepage == 0x3F) {
+                        sd_printk(KERN_ERR, sdkp, "No Caching mode page "
+                                  "present\n");
+                        goto defaults;
+                } else if ((buffer[offset] & 0x3f) != modepage) {
                         sd_printk(KERN_ERR, sdkp, "Got wrong page\n");
                         goto defaults;
                 }
-
+        Page_found:
                 if (modepage == 8) {
                         sdkp->WCE = ((buffer[offset + 2] & 0x04) != 0);
                         sdkp->RCD = ((buffer[offset + 2] & 0x01) != 0);