block: move dma drain handling to scsi

Don't burden the common block code with with specifics of the libata DMA
draining mechanism.  Instead move most of the code to the scsi midlayer.

That also means the nr_phys_segments adjustments in the blk-mq fast path
can go away entirely, given that SCSI never looks at nr_phys_segments
after mapping the request to a scatterlist.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig
2020-04-14 09:42:24 +02:00
committed by Jens Axboe
parent 0475bd6c65
commit cc97923a5b
9 changed files with 56 additions and 92 deletions

View File

@@ -1092,6 +1092,7 @@ extern int ata_scsi_ioctl(struct scsi_device *dev, unsigned int cmd,
#define ATA_SCSI_COMPAT_IOCTL /* empty */
#endif
extern int ata_scsi_queuecmd(struct Scsi_Host *h, struct scsi_cmnd *cmd);
bool ata_scsi_dma_need_drain(struct request *rq);
extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *dev,
unsigned int cmd, void __user *arg);
extern bool ata_link_online(struct ata_link *link);
@@ -1387,6 +1388,7 @@ extern struct device_attribute *ata_common_sdev_attrs[];
.ioctl = ata_scsi_ioctl, \
ATA_SCSI_COMPAT_IOCTL \
.queuecommand = ata_scsi_queuecmd, \
.dma_need_drain = ata_scsi_dma_need_drain, \
.can_queue = ATA_DEF_QUEUE, \
.tag_alloc_policy = BLK_TAG_ALLOC_RR, \
.this_id = ATA_SHT_THIS_ID, \