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 <dgilbert@xxxxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
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
