block: restore the meaning of rq->data_len to the true data length

The meaning of rq->data_len was changed to the length of an allocated
buffer from the true data length. It breaks SG_IO friends and
bsg. This patch restores the meaning of rq->data_len to the true data
length and adds rq->extra_len to store an extended length (due to
drain buffer and padding).

This patch also removes the code to update bio in blk_rq_map_user
introduced by the commit 40b01b9bbdf51ae543a04744283bf2d56c4a6afa.
The commit adjusts bio according to memory alignment
(queue_dma_alignment). However, memory alignment is NOT padding
alignment. This adjustment also breaks SG_IO friends and bsg. Padding
alignment needs to be fixed in a proper way (by a separate patch).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>

diff --git a/block/blk-core.c b/block/blk-core.c
index 2d7e3a2..a248cf1 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -127,7 +127,6 @@ void rq_init(struct request_queue *q, struct request *rq)
        rq->nr_hw_segments = 0;
        rq->ioprio = 0;
        rq->special = NULL;
-       rq->raw_data_len = 0;
        rq->buffer = NULL;
        rq->tag = -1;
        rq->errors = 0;
@@ -135,6 +134,7 @@ void rq_init(struct request_queue *q, struct request *rq)
        rq->cmd_len = 0;
        memset(rq->cmd, 0, sizeof(rq->cmd));
        rq->data_len = 0;
+       rq->extra_len = 0;
        rq->sense_len = 0;
        rq->data = NULL;
        rq->sense = NULL;
@@ -2018,7 +2018,6 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
        rq->hard_cur_sectors = rq->current_nr_sectors;
        rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio);
        rq->buffer = bio_data(bio);
-       rq->raw_data_len = bio->bi_size;
        rq->data_len = bio->bi_size;
 
        rq->bio = rq->biotail = bio;

diff --git a/block/blk-map.c b/block/blk-map.c
index 09f7fd0..f559832 100644 (file)
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -19,7 +19,6 @@ int blk_rq_append_bio(struct request_queue *q, struct request *rq,
                rq->biotail->bi_next = bio;
                rq->biotail = bio;
 
-               rq->raw_data_len += bio->bi_size;
                rq->data_len += bio->bi_size;
        }
        return 0;
@@ -151,11 +150,8 @@ int blk_rq_map_user(struct request_queue *q, struct request *rq,
         */
        if (len & queue_dma_alignment(q)) {
                unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1;
-               struct bio *bio = rq->biotail;
 
-               bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
-               bio->bi_size += pad_len;
-               rq->data_len += pad_len;
+               rq->extra_len += pad_len;
        }
 
        rq->buffer = rq->data = NULL;

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 7506c4f..0f58616 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -231,7 +231,7 @@ new_segment:
                            ((unsigned long)q->dma_drain_buffer) &
                            (PAGE_SIZE - 1));
                nsegs++;
-               rq->data_len += q->dma_drain_size;
+               rq->extra_len += q->dma_drain_size;
        }
 
        if (sg)

diff --git a/block/bsg.c b/block/bsg.c
index 7f3c095..8917c51 100644 (file)
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -437,14 +437,14 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
        }
 
        if (rq->next_rq) {
-               hdr->dout_resid = rq->raw_data_len;
-               hdr->din_resid = rq->next_rq->raw_data_len;
+               hdr->dout_resid = rq->data_len;
+               hdr->din_resid = rq->next_rq->data_len;
                blk_rq_unmap_user(bidi_bio);
                blk_put_request(rq->next_rq);
        } else if (rq_data_dir(rq) == READ)
-               hdr->din_resid = rq->raw_data_len;
+               hdr->din_resid = rq->data_len;
        else
-               hdr->dout_resid = rq->raw_data_len;
+               hdr->dout_resid = rq->data_len;
 
        /*
         * If the request generated a negative error number, return it

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index e993cac..a2c3a93 100644 (file)
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -266,7 +266,7 @@ static int blk_complete_sghdr_rq(struct request *rq, struct sg_io_hdr *hdr,
        hdr->info = 0;
        if (hdr->masked_status || hdr->host_status || hdr->driver_status)
                hdr->info |= SG_INFO_CHECK;
-       hdr->resid = rq->raw_data_len;
+       hdr->resid = rq->data_len;
        hdr->sb_len_wr = 0;
 
        if (rq->sense_len && hdr->sbp) {
@@ -528,8 +528,8 @@ static int __blk_send_generic(struct request_queue *q, struct gendisk *bd_disk,
        rq = blk_get_request(q, WRITE, __GFP_WAIT);
        rq->cmd_type = REQ_TYPE_BLOCK_PC;
        rq->data = NULL;
-       rq->raw_data_len = 0;
        rq->data_len = 0;
+       rq->extra_len = 0;
        rq->timeout = BLK_DEFAULT_SG_TIMEOUT;
        memset(rq->cmd, 0, sizeof(rq->cmd));
        rq->cmd[0] = cmd;

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7b1f1ee..fe47922 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2538,7 +2538,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
        }
 
        qc->tf.command = ATA_CMD_PACKET;
-       qc->nbytes = scsi_bufflen(scmd);
+       qc->nbytes = scsi_bufflen(scmd) + scmd->request->extra_len;
 
        /* check whether ATAPI DMA is safe */
        if (!using_pio && ata_check_atapi_dma(qc))
@@ -2549,7 +2549,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
         * want to set it properly, and for DMA where it is
         * effectively meaningless.
         */
-       nbytes = min(scmd->request->raw_data_len, (unsigned int)63 * 1024);
+       nbytes = min(scmd->request->data_len, (unsigned int)63 * 1024);
 
        /* Most ATAPI devices which honor transfer chunk size don't
         * behave according to the spec when odd chunk size which
@@ -2875,7 +2875,7 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
         * TODO: find out if we need to do more here to
         *       cover scatter/gather case.
         */
-       qc->nbytes = scsi_bufflen(scmd);
+       qc->nbytes = scsi_bufflen(scmd) + scmd->request->extra_len;
 
        /* request result TF and be quiet about device error */
        qc->flags |= ATA_QCFLAG_RESULT_TF | ATA_QCFLAG_QUIET;

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6fe67d1..b72526c 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -216,8 +216,8 @@ struct request {
        unsigned int cmd_len;
        unsigned char cmd[BLK_MAX_CDB];
 
-       unsigned int raw_data_len;
        unsigned int data_len;
+       unsigned int extra_len; /* length of alignment and padding */
        unsigned int sense_len;
        void *data;
        void *sense;