This is a note to let you know that I've just added the patch titled
scsi: core: Don't memset() the entire scsi_cmnd in scsi_init_command()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-core-don-t-memset-the-entire-scsi_cmnd-in-scsi_.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 3039005b7ab8db780c75d240d5c329f48129722b
Author: Christoph Hellwig <hch@xxxxxx>
Date: Thu Feb 24 18:55:46 2022 +0100
scsi: core: Don't memset() the entire scsi_cmnd in scsi_init_command()
[ Upstream commit 71bada345b33b9297e7cc9415db6328c99b554f9 ]
Replace the big fat memset that requires saving and restoring various
fields with just initializing those fields that need initialization.
All the clearing to 0 is moved to scsi_prepare_cmd() as scsi_ioctl_reset()
alreadly uses kzalloc() to allocate a pre-zeroed command.
This is still conservative and can probably be optimized further.
Link: https://lore.kernel.org/r/20220224175552.988286-3-hch@xxxxxx
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: John Garry <john.garry@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Stable-dep-of: dce5c4afd035 ("scsi: core: Clear driver private data when retrying request")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9721984fd9bc6..ddaffaea2c32c 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1114,45 +1114,16 @@ static void scsi_cleanup_rq(struct request *rq)
/* 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;
- void *prot = cmd->prot_sdb;
struct request *rq = scsi_cmd_to_rq(cmd);
- unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
- unsigned long jiffies_at_alloc;
- int retries, to_clear;
- bool in_flight;
- int budget_token = cmd->budget_token;
-
- if (!blk_rq_is_passthrough(rq) && !(flags & SCMD_INITIALIZED)) {
- flags |= SCMD_INITIALIZED;
+
+ if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
+ cmd->flags |= SCMD_INITIALIZED;
scsi_initialize_rq(rq);
}
- 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. 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;
- cmd->prot_sdb = prot;
- cmd->flags = flags;
INIT_LIST_HEAD(&cmd->eh_entry);
INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
- cmd->jiffies_at_alloc = jiffies_at_alloc;
- cmd->retries = retries;
- if (in_flight)
- __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
- cmd->budget_token = budget_token;
-
}
static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
@@ -1539,10 +1510,35 @@ static blk_status_t scsi_prepare_cmd(struct request *req)
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
struct scsi_device *sdev = req->q->queuedata;
struct Scsi_Host *shost = sdev->host;
+ bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
struct scatterlist *sg;
scsi_init_command(sdev, cmd);
+ cmd->eh_eflags = 0;
+ cmd->allowed = 0;
+ cmd->prot_type = 0;
+ cmd->prot_flags = 0;
+ cmd->submitter = 0;
+ cmd->cmd_len = 0;
+ cmd->cmnd = NULL;
+ memset(&cmd->sdb, 0, sizeof(cmd->sdb));
+ cmd->underflow = 0;
+ cmd->transfersize = 0;
+ cmd->host_scribble = NULL;
+ cmd->result = 0;
+ cmd->extra_len = 0;
+ cmd->state = 0;
+ if (in_flight)
+ __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
+
+ /*
+ * Only clear the driver-private command data if the LLD does not supply
+ * a function to initialize that data.
+ */
+ if (!shost->hostt->init_cmd_priv)
+ memset(cmd + 1, 0, shost->hostt->cmd_size);
+
cmd->prot_op = SCSI_PROT_NORMAL;
if (blk_rq_bytes(req))
cmd->sc_data_direction = rq_dma_dir(req);
