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-rw-r--r--drivers/scsi/sd.c21
-rw-r--r--drivers/scsi/sd.h6
-rw-r--r--include/scsi/scsi_device.h3
3 files changed, 7 insertions, 23 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index e5e7d7856454..8e08d51a0f05 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -375,7 +375,6 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
struct gendisk *disk = rq->rq_disk;
struct scsi_disk *sdkp;
sector_t block = rq->sector;
- sector_t threshold;
unsigned int this_count = rq->nr_sectors;
unsigned int timeout = sdp->timeout;
int ret;
@@ -423,21 +422,13 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
}
/*
- * Some SD card readers can't handle multi-sector accesses which touch
- * the last one or two hardware sectors. Split accesses as needed.
+ * Some devices (some sdcards for one) don't like it if the
+ * last sector gets read in a larger then 1 sector read.
*/
- threshold = get_capacity(disk) - SD_LAST_BUGGY_SECTORS *
- (sdp->sector_size / 512);
-
- if (unlikely(sdp->last_sector_bug && block + this_count > threshold)) {
- if (block < threshold) {
- /* Access up to the threshold but not beyond */
- this_count = threshold - block;
- } else {
- /* Access only a single hardware sector */
- this_count = sdp->sector_size / 512;
- }
- }
+ if (unlikely(sdp->last_sector_bug &&
+ rq->nr_sectors > sdp->sector_size / 512 &&
+ block + this_count == get_capacity(disk)))
+ this_count -= sdp->sector_size / 512;
SCSI_LOG_HLQUEUE(2, scmd_printk(KERN_INFO, SCpnt, "block=%llu\n",
(unsigned long long)block));
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 95b9f06534d5..550b2f70a1f8 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -31,12 +31,6 @@
*/
#define SD_BUF_SIZE 512
-/*
- * Number of sectors at the end of the device to avoid multi-sector
- * accesses to in the case of last_sector_bug
- */
-#define SD_LAST_BUGGY_SECTORS 8
-
struct scsi_disk {
struct scsi_driver *driver; /* always &sd_template */
struct scsi_device *device;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 291d56a19167..9cecc409f0f8 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -140,8 +140,7 @@ struct scsi_device {
unsigned fix_capacity:1; /* READ_CAPACITY is too high by 1 */
unsigned guess_capacity:1; /* READ_CAPACITY might be too high by 1 */
unsigned retry_hwerror:1; /* Retry HARDWARE_ERROR */
- unsigned last_sector_bug:1; /* do not use multisector accesses on
- SD_LAST_BUGGY_SECTORS */
+ unsigned last_sector_bug:1; /* Always read last sector in a 1 sector read */
DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
struct list_head event_list; /* asserted events */