This patch slightly increases the size of struct scsi_cmnd if data protection is disabled, decreases the size of the data appended at the end of struct scsi_cmnd if data protection is enabled and simplifies the SCSI core.
Cc: Douglas Gilbert <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Christoph Hellwig <[email protected]> Signed-off-by: Bart Van Assche <[email protected]> --- drivers/scsi/scsi_lib.c | 33 ++++++++++++--------------------- include/scsi/scsi_cmnd.h | 8 ++++---- 2 files changed, 16 insertions(+), 25 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 94842b104bcc..6bfbe50ef38e 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -566,7 +566,7 @@ static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd) sg_free_table_chained(&sdb->table, true); } if (scsi_prot_sg_count(cmd)) - sg_free_table_chained(&cmd->prot_sdb->table, true); + sg_free_table_chained(&cmd->prot_sdb.table, true); } static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) @@ -1065,10 +1065,10 @@ blk_status_t scsi_init_io(struct scsi_cmnd *cmd) } if (blk_integrity_rq(rq)) { - struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; + struct scsi_data_buffer *prot_sdb = &cmd->prot_sdb; int ivecs, count; - if (WARN_ON_ONCE(!prot_sdb)) { + if (WARN_ON_ONCE(!scsi_host_get_prot(cmd->device->host))) { /* * This can happen if someone (e.g. multipath) * queues a command to a device on an adapter @@ -1091,8 +1091,7 @@ blk_status_t scsi_init_io(struct scsi_cmnd *cmd) BUG_ON(count > ivecs); BUG_ON(count > queue_max_integrity_segments(rq->q)); - cmd->prot_sdb = prot_sdb; - cmd->prot_sdb->table.nents = count; + prot_sdb->table.nents = count; } return BLK_STS_OK; @@ -1156,7 +1155,6 @@ void scsi_del_cmd_from_list(struct scsi_cmnd *cmd) void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) { void *buf = cmd->sense_buffer; - void *prot = cmd->prot_sdb; struct request *rq = blk_mq_rq_from_pdu(cmd); unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS; unsigned long jiffies_at_alloc; @@ -1175,7 +1173,6 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) cmd->device = dev; cmd->sense_buffer = buf; - cmd->prot_sdb = prot; cmd->flags = flags; INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); cmd->jiffies_at_alloc = jiffies_at_alloc; @@ -1617,12 +1614,13 @@ static blk_status_t scsi_mq_prep_fn(struct request *req) sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; cmd->sdb.table.sgl = sg; - if (scsi_host_get_prot(shost)) { - memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); - - cmd->prot_sdb->table.sgl = - (struct scatterlist *)(cmd->prot_sdb + 1); - } + /* + * Always initialize cmd->prot_sdb.nents such that + * scsi_prot_sg_count() does not have to call scsi_host_get_prot(). + */ + memset(&cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); + if (scsi_host_get_prot(shost)) + cmd->prot_sdb.table.sgl = (void *)&sg + scsi_mq_sgl_size(shost); if (blk_bidi_rq(req)) { struct request *next_rq = req->next_rq; @@ -1781,7 +1779,6 @@ static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, struct Scsi_Host *shost = set->driver_data; const bool unchecked_isa_dma = shost->unchecked_isa_dma; struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); - struct scatterlist *sg; if (unchecked_isa_dma) cmd->flags |= SCMD_UNCHECKED_ISA_DMA; @@ -1791,12 +1788,6 @@ static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, return -ENOMEM; cmd->req.sense = cmd->sense_buffer; - if (scsi_host_get_prot(shost)) { - sg = (void *)cmd + sizeof(struct scsi_cmnd) + - shost->hostt->cmd_size; - cmd->prot_sdb = (void *)sg + scsi_mq_sgl_size(shost); - } - return 0; } @@ -1893,7 +1884,7 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) sgl_size = scsi_mq_sgl_size(shost); cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; if (scsi_host_get_prot(shost)) - cmd_size += sizeof(struct scsi_data_buffer) + sgl_size; + cmd_size += sgl_size; memset(&shost->tag_set, 0, sizeof(shost->tag_set)); shost->tag_set.ops = &scsi_mq_ops; diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index d85e6befa26b..0406c0fbee3e 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -108,7 +108,7 @@ struct scsi_cmnd { /* These elements define the operation we ultimately want to perform */ struct scsi_data_buffer sdb; - struct scsi_data_buffer *prot_sdb; + struct scsi_data_buffer prot_sdb; unsigned underflow; /* Return error if less than this amount is transferred */ @@ -318,17 +318,17 @@ static inline unsigned int scsi_prot_interval(struct scsi_cmnd *scmd) static inline unsigned scsi_prot_sg_count(struct scsi_cmnd *cmd) { - return cmd->prot_sdb ? cmd->prot_sdb->table.nents : 0; + return cmd->prot_sdb.table.nents; } static inline struct scatterlist *scsi_prot_sglist(struct scsi_cmnd *cmd) { - return cmd->prot_sdb ? cmd->prot_sdb->table.sgl : NULL; + return cmd->prot_sdb.table.sgl; } static inline struct scsi_data_buffer *scsi_prot(struct scsi_cmnd *cmd) { - return cmd->prot_sdb; + return &cmd->prot_sdb; } #define scsi_for_each_prot_sg(cmd, sg, nseg, __i) \ -- 2.20.1.321.g9e740568ce-goog
