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Revert "[SCSI] extend the last_sector_bug flag to cover more sectors"

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This reverts commit 2b14290078, since it
seems to break some other USB storage devices (at least a JMicron USB to
ATA bridge).  As such, while it apparently fixes some cardreaders, it
would need to be made conditional on the exact reader it fixes in order
to avoid causing regressions.

Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
2008-08-04 16:36:20 -07:00
parent 8f616cd524
commit fca082c9f1
3 changed files with 7 additions and 23 deletions
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21
drivers/scsi/sd.c
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@@ -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));