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authorBart Van Assche <bvanassche@acm.org>2020-01-22 19:56:34 -0800
committerMartin K. Petersen <martin.petersen@oracle.com>2020-02-28 21:02:10 -0500
commit65ca846a53149a1a72cd8d02e7b2e73dd545b834 (patch)
treed2e9861db4c83b97138fc43bb18c92ba9e1a14b0 /drivers
parentc5a9707672fe22865d90fc04ac2fbc4f812666f3 (diff)
downloadlinux-65ca846a53149a1a72cd8d02e7b2e73dd545b834.tar.bz2
scsi: core: Introduce {init,exit}_cmd_priv()
The current behavior of the SCSI core is to clear driver-private data before preparing a request for submission to the SCSI LLD. Make it possible for SCSI LLDs to disable clearing of driver-private data. These hooks will be used by a later patch, namely "scsi: ufs: Let the SCSI core allocate per-command UFS data". Link: https://lore.kernel.org/r/20200123035637.21848-2-bvanassche@acm.org Cc: Tomas Winkler <tomas.winkler@intel.com> Cc: Stanley Chu <stanley.chu@mediatek.com> Cc: Bean Huo <beanhuo@micron.com> Cc: Avri Altman <avri.altman@wdc.com> Cc: Can Guo <cang@codeaurora.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Johannes Thumshirn <jth@kernel.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/scsi/scsi_lib.c29
1 files changed, 23 insertions, 6 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 258a428a0a3f..9f201194c46a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1097,7 +1097,7 @@ static void scsi_cleanup_rq(struct request *rq)
}
}
-/* Called after a request has been started. */
+/* Called before a request is prepared. See also scsi_mq_prep_fn(). */
void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
{
void *buf = cmd->sense_buffer;
@@ -1105,7 +1105,7 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
struct request *rq = blk_mq_rq_from_pdu(cmd);
unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
unsigned long jiffies_at_alloc;
- int retries;
+ int retries, to_clear;
bool in_flight;
if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
@@ -1116,9 +1116,15 @@ void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
jiffies_at_alloc = cmd->jiffies_at_alloc;
retries = cmd->retries;
in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
- /* zero out the cmd, except for the embedded scsi_request */
- memset((char *)cmd + sizeof(cmd->req), 0,
- sizeof(*cmd) - sizeof(cmd->req) + dev->host->hostt->cmd_size);
+ /*
+ * Zero out the cmd, except for the embedded scsi_request. Only clear
+ * the driver-private command data if the LLD does not supply a
+ * function to initialize that data.
+ */
+ to_clear = sizeof(*cmd) - sizeof(cmd->req);
+ if (!dev->host->hostt->init_cmd_priv)
+ to_clear += dev->host->hostt->cmd_size;
+ memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
cmd->device = dev;
cmd->sense_buffer = buf;
@@ -1711,6 +1717,7 @@ static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
const bool unchecked_isa_dma = shost->unchecked_isa_dma;
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
struct scatterlist *sg;
+ int ret = 0;
if (unchecked_isa_dma)
cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
@@ -1726,14 +1733,24 @@ static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
}
- return 0;
+ if (shost->hostt->init_cmd_priv) {
+ ret = shost->hostt->init_cmd_priv(shost, cmd);
+ if (ret < 0)
+ scsi_free_sense_buffer(unchecked_isa_dma,
+ cmd->sense_buffer);
+ }
+
+ return ret;
}
static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
unsigned int hctx_idx)
{
+ struct Scsi_Host *shost = set->driver_data;
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
+ if (shost->hostt->exit_cmd_priv)
+ shost->hostt->exit_cmd_priv(shost, cmd);
scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
cmd->sense_buffer);
}