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Subject[68/71] [SCSI] Revert "[SCSI] Retrieve the Caching mode page"
2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------

From: James Bottomley <James.Bottomley@suse.de>

commit 3dea642afd9187728d119fce5c82a7ed9faa9b6a upstream.

This reverts commit 24d720b726c1a85f1962831ac30ad4d2ef8276b1.

Previously we thought there was little possibility that devices would
crash with this, but some have been found.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/scsi/sd.c | 63 +++++++++++++-----------------------------------------
1 file changed, 16 insertions(+), 47 deletions(-)

--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1910,14 +1910,10 @@ sd_read_cache_type(struct scsi_disk *sdk
int old_rcd = sdkp->RCD;
int old_dpofua = sdkp->DPOFUA;

- if (sdp->skip_ms_page_8) {
- if (sdp->type == TYPE_RBC)
- goto defaults;
- else {
- modepage = 0x3F;
- dbd = 0;
- }
- } else if (sdp->type == TYPE_RBC) {
+ if (sdp->skip_ms_page_8)
+ goto defaults;
+
+ if (sdp->type == TYPE_RBC) {
modepage = 6;
dbd = 8;
} else {
@@ -1945,11 +1941,13 @@ sd_read_cache_type(struct scsi_disk *sdk
*/
if (len < 3)
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 (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;

/* Get the data */
res = sd_do_mode_sense(sdp, dbd, modepage, buffer, len, &data, &sshdr);
@@ -1957,45 +1955,16 @@ sd_read_cache_type(struct scsi_disk *sdk
if (scsi_status_is_good(res)) {
int offset = data.header_length + data.block_descriptor_length;

- 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 (offset >= SD_BUF_SIZE - 2) {
+ sd_printk(KERN_ERR, sdkp, "Malformed MODE SENSE response\n");
+ goto defaults;
}

- if (modepage == 0x3F) {
- sd_printk(KERN_ERR, sdkp, "No Caching mode page "
- "present\n");
- goto defaults;
- } else if ((buffer[offset] & 0x3f) != modepage) {
+ 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);



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