Hello.
On 03-02-2012 16:59, Amit Sahrawat wrote:
It has been observed that a number of USB HDD's do not respond correctly
Why are you working around this in libata-scsi.c then if it's USB HDD?
to SCSI mode sense command(retrieve caching pages) which results in their
Write Cache being discarded by queue requests i.e., WCE if left set to
'0'(disabled).
This results in a number of Filesystem corruptions, when the device
is unplugged abruptly.
So, in order to identify the devices correctly - give it
a last try using ATA_16 after failure from normal routine.
Shouldn't this be done in drivers/usb/storage somewhere?
Signed-off-by: Amit Sahrawat<a.sahrawat@xxxxxxxxxxx>
Signed-off-by: Namjae Jeon<namjae.jeon@xxxxxxxxxxx>
[...]
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 508a60b..d5b00e6 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -562,6 +562,57 @@ error:
}
/**
+ * ata_get_cachestatus - Handler for to get WriteCache Status
+ * using ATA_16 scsi command
+ * @scsidev: Device to which we are issuing command
+ *
+ * LOCKING:
+ * Defined by the SCSI layer. We don't really care.
+ *
+ * RETURNS:
+ * '0' for Write Cache Disabled and on any error.
+ * '1' for Write Cache enabled
+ */
+int ata_get_cachestatus(struct scsi_device *scsidev)
+{
+ int rc = 0;
+ u8 scsi_cmd[MAX_COMMAND_SIZE] = {0};
+ u8 *sensebuf = NULL, *argbuf = NULL;
No need to initialize them.
+ enum dma_data_direction data_dir;
+
+ sensebuf = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
+ if (!sensebuf)
+ return rc;
+
+ argbuf = kmalloc(ATA_SECT_SIZE, GFP_KERNEL);
+ if (argbuf == NULL)
Could you use an uniform NULL-check, either '!x' or 'x == NULL'?
+ goto error;
+
+ scsi_cmd[0] = ATA_16;
+ scsi_cmd[1] = (4<< 1); /* PIO Data-in */
+ scsi_cmd[2] = 0x0e; /* no off.line or cc, read from dev,
+ block count in sector count field */
+ data_dir = DMA_FROM_DEVICE;
+ scsi_cmd[14] = ATA_IDENTIFY_DEV;
+
+ if (!scsi_execute(scsidev, scsi_cmd, data_dir, argbuf, ATA_SECT_SIZE,
+ sensebuf, (10*HZ), 5, 0, NULL)) {
+ /*
+ * '6th' Bit in Word 85 Corresponds to Write Cache
No need for apostrophes here.
+ * being Enabled/disabled, Word 85 represnets the
+ * features supported
+ */
+ if (le16_to_cpu(((unsigned short *)argbuf)[85])& 0x20)
+ rc = 1;
+ }
+
+error:
+ kfree(sensebuf);
+ kfree(argbuf);
+ return rc;
+}
+
+/**
* ata_task_ioctl - Handler for HDIO_DRIVE_TASK ioctl
* @scsidev: Device to which we are issuing command
* @arg: User provided data for issuing command
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c691fb5..a6b887d 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -50,6 +50,11 @@
#include<linux/string_helpers.h>
#include<linux/async.h>
#include<linux/slab.h>
+
+#ifdef CONFIG_ATA
#ifdef not necessary here.
+#include<linux/libata.h>
+#endif
+
#include<linux/pm_runtime.h>
#include<asm/uaccess.h>
#include<asm/unaligned.h>
@@ -2129,7 +2134,11 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
if (modepage == 0x3F) {
sd_printk(KERN_ERR, sdkp, "No Caching mode page "
"present\n");
+#ifdef CONFIG_ATA
+ goto WCE_USING_ATA;
Yikes.
+#else
goto defaults;
+#endif
} else if ((buffer[offset]& 0x3f) != modepage) {
sd_printk(KERN_ERR, sdkp, "Got wrong page\n");
goto defaults;
@@ -2149,6 +2158,14 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
"Uses READ/WRITE(6), disabling FUA\n");
sdkp->DPOFUA = 0;
}
+#ifdef CONFIG_ATA
+WCE_USING_ATA:
+ if (!sdp->removable && !sdkp->WCE) {
+ sd_printk(KERN_NOTICE, sdkp, "Try to check write cache "
+ "enable/disable using ATA command\n");
+ sdkp->WCE = ata_get_cachestatus(sdp);
+ }
+#endif
if (sdkp->first_scan || old_wce != sdkp->WCE ||
old_rcd != sdkp->RCD || old_dpofua != sdkp->DPOFUA)
diff --git a/include/linux/libata.h b/include/linux/libata.h
index cafc09a..33fc73f 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -84,6 +84,8 @@
} \
})
+#define ATA_IDENTIFY_DEV 0xEC
+
This is alerady #defined in <linux/ata.h> as ATA_CMD_ID_ATA.
MBR, Sergei
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