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authorJames Bottomley <James.Bottomley@HansenPartnership.com>2008-02-19 05:36:57 -0500
committerJens Axboe <jens.axboe@oracle.com>2008-02-19 05:36:57 -0500
commitfa2fc7f4813bfec1ae3232d49e3befbd601e8a6f (patch)
treef5598bd35f38812318da493cc027238a2256e036 /drivers/ata/libata-core.c
parentdde2020754aeb14e17052d61784dcb37f252aac2 (diff)
libata: implement drain buffers
This just updates the libata slave configure routine to take advantage of the block layer drain buffers. It also adjusts the size lengths in the atapi code to add the drain buffer to the DMA length so the driver knows it can rely on it. I suspect I should also be checking for AHCI as well as ATA_DEV_ATAPI, but I couldn't see how to do that easily. tj: * atapi_drain_needed() added such that draining is applied to only misc ATAPI commands. * q->bounce_gfp used when allocating drain buffer. * Now duplicate ATAPI PIO drain logic dropped. * ata_dev_printk() used instead of sdev_printk(). Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers/ata/libata-core.c')
-rw-r--r--drivers/ata/libata-core.c56
1 files changed, 4 insertions, 52 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 3587ac3fe3f3..def3682f416a 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4642,28 +4642,6 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc)
4642} 4642}
4643 4643
4644/** 4644/**
4645 * atapi_qc_may_overflow - Check whether data transfer may overflow
4646 * @qc: ATA command in question
4647 *
4648 * ATAPI commands which transfer variable length data to host
4649 * might overflow due to application error or hardare bug. This
4650 * function checks whether overflow should be drained and ignored
4651 * for @qc.
4652 *
4653 * LOCKING:
4654 * None.
4655 *
4656 * RETURNS:
4657 * 1 if @qc may overflow; otherwise, 0.
4658 */
4659static int atapi_qc_may_overflow(struct ata_queued_cmd *qc)
4660{
4661 return ata_is_atapi(qc->tf.protocol) && ata_is_data(qc->tf.protocol) &&
4662 atapi_cmd_type(qc->cdb[0]) == ATAPI_MISC &&
4663 !(qc->tf.flags & ATA_TFLAG_WRITE);
4664}
4665
4666/**
4667 * ata_std_qc_defer - Check whether a qc needs to be deferred 4645 * ata_std_qc_defer - Check whether a qc needs to be deferred
4668 * @qc: ATA command in question 4646 * @qc: ATA command in question
4669 * 4647 *
@@ -5026,36 +5004,10 @@ static int __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
5026next_sg: 5004next_sg:
5027 sg = qc->cursg; 5005 sg = qc->cursg;
5028 if (unlikely(!sg)) { 5006 if (unlikely(!sg)) {
5029 /* 5007 ata_ehi_push_desc(ehi, "unexpected or too much trailing data "
5030 * The end of qc->sg is reached and the device expects 5008 "buf=%u cur=%u bytes=%u",
5031 * more data to transfer. In order not to overrun qc->sg 5009 qc->nbytes, qc->curbytes, bytes);
5032 * and fulfill length specified in the byte count register, 5010 return -1;
5033 * - for read case, discard trailing data from the device
5034 * - for write case, padding zero data to the device
5035 */
5036 u16 pad_buf[1] = { 0 };
5037
5038 if (qc->curbytes + bytes > qc->nbytes + ATAPI_MAX_DRAIN) {
5039 ata_ehi_push_desc(ehi, "too much trailing data "
5040 "buf=%u cur=%u bytes=%u",
5041 qc->nbytes, qc->curbytes, bytes);
5042 return -1;
5043 }
5044
5045 /* allow overflow only for misc ATAPI commands */
5046 if (!atapi_qc_may_overflow(qc)) {
5047 ata_ehi_push_desc(ehi, "unexpected trailing data "
5048 "%u bytes", bytes);
5049 return -1;
5050 }
5051
5052 consumed = 0;
5053 while (consumed < bytes)
5054 consumed += ap->ops->data_xfer(dev,
5055 (unsigned char *)pad_buf, 2, rw);
5056
5057 qc->curbytes += bytes;
5058 return 0;
5059 } 5011 }
5060 5012
5061 page = sg_page(sg); 5013 page = sg_page(sg);