From: Matthew Wilcox <matthew@xxxxxx>
The sd_read_capacity() function was about 180 lines long and
included a backwards goto and a tricky state variable. Splitting out
read_capacity_10() and read_capacity_16() (about 50 lines each) reduces
sd_read_capacity to about 100 lines and gets rid of the backwards goto
and the state variable. I've tried to avoid any behaviour change with
this patch.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
drivers/scsi/sd.c | 247 ++++++++++++++++++++++++++++++++++-------------------
1 files changed, 158 insertions(+), 89 deletions(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 55310db..6cf0c25 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1277,42 +1277,61 @@ disable:
sdkp->capacity = 0;
}
-/*
- * read disk capacity
- */
-static void
-sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
+static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
+ struct scsi_sense_hdr *sshdr, int sense_valid,
+ int the_result)
+{
+ sd_print_result(sdkp, the_result);
+ if (driver_byte(the_result) & DRIVER_SENSE)
+ sd_print_sense_hdr(sdkp, sshdr);
+ else
+ sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");
+
+ /*
+ * Set dirty bit for removable devices if not ready -
+ * sometimes drives will not report this properly.
+ */
+ if (sdp->removable &&
+ sense_valid && sshdr->sense_key == NOT_READY)
+ sdp->changed = 1;
+
+ /*
+ * We used to set media_present to 0 here to indicate no media
+ * in the drive, but some drives fail read capacity even with
+ * media present, so we can't do that.
+ */
+ sdkp->capacity = 0; /* unknown mapped to zero - as usual */
+}
+
+#define RC16_LEN 13
+#if RC16_LEN > SD_BUF_SIZE
+#error RC16_LEN must not be more than SD_BUF_SIZE
+#endif
+
+static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
+ unsigned char *buffer)
{
unsigned char cmd[16];
- int the_result, retries;
- int sector_size = 0;
- /* Force READ CAPACITY(16) when PROTECT=1 */
- int longrc = scsi_device_protection(sdkp->device) ? 1 : 0;
struct scsi_sense_hdr sshdr;
int sense_valid = 0;
- struct scsi_device *sdp = sdkp->device;
+ int the_result;
+ int retries = 3;
+ unsigned long long lba;
+ unsigned sector_size;
-repeat:
- retries = 3;
do {
- if (longrc) {
- memset((void *) cmd, 0, 16);
- cmd[0] = SERVICE_ACTION_IN;
- cmd[1] = SAI_READ_CAPACITY_16;
- cmd[13] = 13;
- memset((void *) buffer, 0, 13);
- } else {
- cmd[0] = READ_CAPACITY;
- memset((void *) &cmd[1], 0, 9);
- memset((void *) buffer, 0, 8);
- }
-
+ memset(cmd, 0, 16);
+ cmd[0] = SERVICE_ACTION_IN;
+ cmd[1] = SAI_READ_CAPACITY_16;
+ cmd[13] = RC16_LEN;
+ memset(buffer, 0, RC16_LEN);
+
the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
- buffer, longrc ? 13 : 8, &sshdr,
- SD_TIMEOUT, SD_MAX_RETRIES, NULL);
+ buffer, RC16_LEN, &sshdr,
+ SD_TIMEOUT, SD_MAX_RETRIES, NULL);
if (media_not_present(sdkp, &sshdr))
- return;
+ return -ENODEV;
if (the_result)
sense_valid = scsi_sense_valid(&sshdr);
@@ -1320,72 +1339,122 @@ repeat:
} while (the_result && retries);
- if (the_result && !longrc) {
+ if (the_result) {
+ sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
+ read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
+ return -EINVAL;
+ }
+
+ sector_size = (buffer[8] << 24) | (buffer[9] << 16) |
+ (buffer[10] << 8) | buffer[11];
+ lba = (((u64)buffer[0] << 56) | ((u64)buffer[1] << 48) |
+ ((u64)buffer[2] << 40) | ((u64)buffer[3] << 32) |
+ ((u64)buffer[4] << 24) | ((u64)buffer[5] << 16) |
+ ((u64)buffer[6] << 8) | (u64)buffer[7]);
+
+ sd_read_protection_type(sdkp, buffer);
+
+ if ((sizeof(sdkp->capacity) == 4) && (lba >= 0xffffffffULL)) {
+ sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
+ "kernel compiled with support for large block "
+ "devices.\n");
+ sdkp->capacity = 0;
+ return -EOVERFLOW;
+ }
+
+ sdkp->capacity = lba + 1;
+ return sector_size;
+}
+
+static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
+ unsigned char *buffer)
+{
+ unsigned char cmd[16];
+ struct scsi_sense_hdr sshdr;
+ int sense_valid = 0;
+ int the_result;
+ int retries = 3;
+ sector_t lba;
+ unsigned sector_size;
+
+ do {
+ cmd[0] = READ_CAPACITY;
+ memset(&cmd[1], 0, 9);
+ memset(buffer, 0, 8);
+
+ the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
+ buffer, 8, &sshdr,
+ SD_TIMEOUT, SD_MAX_RETRIES, NULL);
+
+ if (media_not_present(sdkp, &sshdr))
+ return -ENODEV;
+
+ if (the_result)
+ sense_valid = scsi_sense_valid(&sshdr);
+ retries--;
+
+ } while (the_result && retries);
+
+ if (the_result) {
sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY failed\n");
- sd_print_result(sdkp, the_result);
- if (driver_byte(the_result) & DRIVER_SENSE)
- sd_print_sense_hdr(sdkp, &sshdr);
- else
- sd_printk(KERN_NOTICE, sdkp, "Sense not available.\n");
+ read_capacity_error(sdkp, sdp, &sshdr, sense_valid, the_result);
+ return -EINVAL;
+ }
- /* Set dirty bit for removable devices if not ready -
- * sometimes drives will not report this properly. */
- if (sdp->removable &&
- sense_valid && sshdr.sense_key == NOT_READY)
- sdp->changed = 1;
+ sector_size = (buffer[4] << 24) | (buffer[5] << 16) |
+ (buffer[6] << 8) | buffer[7];
+ lba = (buffer[0] << 24) | (buffer[1] << 16) |
+ (buffer[2] << 8) | buffer[3];
- /* Either no media are present but the drive didn't tell us,
- or they are present but the read capacity command fails */
- /* sdkp->media_present = 0; -- not always correct */
- sdkp->capacity = 0; /* unknown mapped to zero - as usual */
+ if ((sizeof(sdkp->capacity) == 4) && (lba == 0xffffffff)) {
+ sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use a "
+ "kernel compiled with support for large block "
+ "devices.\n");
+ sdkp->capacity = 0;
+ return -EOVERFLOW;
+ }
- return;
- } else if (the_result && longrc) {
- /* READ CAPACITY(16) has been failed */
- sd_printk(KERN_NOTICE, sdkp, "READ CAPACITY(16) failed\n");
- sd_print_result(sdkp, the_result);
- sd_printk(KERN_NOTICE, sdkp, "Use 0xffffffff as device size\n");
+ sdkp->capacity = lba + 1;
+ return sector_size;
+}
- sdkp->capacity = 1 + (sector_t) 0xffffffff;
- goto got_data;
- }
-
- if (!longrc) {
- sector_size = (buffer[4] << 24) |
- (buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
- if (buffer[0] == 0xff && buffer[1] == 0xff &&
- buffer[2] == 0xff && buffer[3] == 0xff) {
- if(sizeof(sdkp->capacity) > 4) {
- sd_printk(KERN_NOTICE, sdkp, "Very big device. "
- "Trying to use READ CAPACITY(16).\n");
- longrc = 1;
- goto repeat;
- }
- sd_printk(KERN_ERR, sdkp, "Too big for this kernel. Use "
- "a kernel compiled with support for large "
- "block devices.\n");
- sdkp->capacity = 0;
+/*
+ * read disk capacity
+ */
+static void
+sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
+{
+ int sector_size;
+ struct scsi_device *sdp = sdkp->device;
+
+ /* Force READ CAPACITY(16) when PROTECT=1 */
+ if (scsi_device_protection(sdp)) {
+ sector_size = read_capacity_16(sdkp, sdp, buffer);
+ if (sector_size == -EOVERFLOW)
goto got_data;
- }
- sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
- (buffer[1] << 16) |
- (buffer[2] << 8) |
- buffer[3]);
+ if (sector_size < 0)
+ return;
} else {
- sdkp->capacity = 1 + (((u64)buffer[0] << 56) |
- ((u64)buffer[1] << 48) |
- ((u64)buffer[2] << 40) |
- ((u64)buffer[3] << 32) |
- ((sector_t)buffer[4] << 24) |
- ((sector_t)buffer[5] << 16) |
- ((sector_t)buffer[6] << 8) |
- (sector_t)buffer[7]);
-
- sector_size = (buffer[8] << 24) |
- (buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
-
- sd_read_protection_type(sdkp, buffer);
- }
+ sector_size = read_capacity_10(sdkp, sdp, buffer);
+ if (sector_size == -EOVERFLOW)
+ goto got_data;
+ if (sector_size < 0)
+ return;
+ if ((sizeof(sdkp->capacity) > 4) &&
+ (sdkp->capacity > 0xffffffffULL)) {
+ int old_sector_size = sector_size;
+ sd_printk(KERN_NOTICE, sdkp, "Very big device. "
+ "Trying to use READ CAPACITY(16).\n");
+ sector_size = read_capacity_16(sdkp, sdp, buffer);
+ if (sector_size < 0) {
+ sd_printk(KERN_NOTICE, sdkp,
+ "Using 0xffffffff as device size\n");
+ sdkp->capacity = 1 + (sector_t) 0xffffffff;
+ sector_size = old_sector_size;
+ goto got_data;
+ }
+ }
+ }
/* Some devices return the total number of sectors, not the
* highest sector number. Make the necessary adjustment. */
--
1.6.1.3
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