Jens Axboe wrote:
On Thu, Apr 23 2009, Jeff Garzik wrote:
Jens Axboe wrote:
+static void sd_read_block_characteristics(struct scsi_disk *sdkp)
+{
+ char *buffer;
+ u16 rot;
+
+ /* Block Device Characteristics VPD */
+ buffer = scsi_get_vpd_page(sdkp->device, 0xb1);
+
+ if (buffer == NULL)
+ return;
+
+ rot = get_unaligned_be16(&buffer[4]);
+
+ if (rot == 1)
+ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, sdkp->disk->queue);
+
+ kfree(buffer);
+}
+
+/**
* sd_revalidate_disk - called the first time a new disk is seen,
* performs disk spin up, read_capacity, etc.
* @disk: struct gendisk we care about
@@ -1836,6 +1860,7 @@ static int sd_revalidate_disk(struct gen
*/
if (sdkp->media_present) {
sd_read_capacity(sdkp, buffer);
+ sd_read_block_characteristics(sdkp);
sd_read_write_protect_flag(sdkp, buffer);
sd_read_cache_type(sdkp, buffer);
sd_read_app_tag_own(sdkp, buffer);
@@ -1976,6 +2001,8 @@ static void sd_probe_async(void *data, a
add_disk(gd);
sd_dif_config_host(sdkp);
+ sd_revalidate_disk(gd);
+
sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
sdp->removable ? "removable " : "");
Make sure this works for libata as well, and then kill the rotational
check in there instead.
Yep. libata-scsi.c would need to simulate that VPD page.
Exactly
Also (to mkp or whoever does the work) -- note Linus's comment, and my
provisional patch[1], about libata potentially wanting to detect NONROT
by looking for "*SSD" from IDENTIFY DEVICE'S model string.
I think that's an entirely orthogonal issue.
Yes.
If somebody is going to be essentially rewriting the libata SSD
detection logic, that area will get stirred _anyway_.
So I hope it is not out of bounds to point out additional areas where a
developer could serve a legitimate need of Linux users, particularly
when doing so is easy and a provisional patch already exists.
Jeff
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