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Wysocki" , David Jeffery , Laurence Oberman Subject: [RFC PATCH 5/6] scsi mid layer support for async command submit Date: Wed, 7 Feb 2024 13:40:59 -0500 Message-ID: <20240207184100.18066-6-djeffery@redhat.com> In-Reply-To: <20240207184100.18066-1-djeffery@redhat.com> References: <20240207184100.18066-1-djeffery@redhat.com> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Create scsi_execute_cmd_nowait to allow asynchronous scsi command submit. Parts of the code originally in scsi_execute_cmd are shifted into helper functions used by both scsi_execute_cmd and the new scsi_execute_cmd_nowait. The scsi_exec_args struct is expanded to contain the fields needed for the completion and callback for the async path. Signed-off-by: David Jeffery Tested-by: Laurence Oberman --- drivers/scsi/scsi_lib.c | 138 +++++++++++++++++++++++++++++-------- include/scsi/scsi_device.h | 8 +++ 2 files changed, 118 insertions(+), 28 deletions(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 1fb80eae9a63..fe35bc2021e3 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -185,42 +185,37 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) } /** - * scsi_execute_cmd - insert request and wait for the result + * scsi_execute_init - helper for setting up a scsi_cmnd in a request * @sdev: scsi_device * @cmd: scsi command * @opf: block layer request cmd_flags - * @buffer: data buffer - * @bufflen: len of buffer * @timeout: request timeout in HZ * @retries: number of times to retry request - * @args: Optional args. See struct definition for field descriptions + * @args: scsi command args * - * Returns the scsi_cmnd result field if a command was executed, or a negative - * Linux error code if we didn't get that far. + * Returns a request if successful, or an error pointer if there was a failure. */ -int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, - blk_opf_t opf, void *buffer, unsigned int bufflen, - int timeout, int retries, - const struct scsi_exec_args *args) +static struct request *scsi_execute_init(struct scsi_device *sdev, + const unsigned char *cmd, + blk_opf_t opf, + int timeout, int retries, + struct scsi_exec_args *args) { - static const struct scsi_exec_args default_args; struct request *req; struct scsi_cmnd *scmd; int ret; - if (!args) - args = &default_args; - else if (WARN_ON_ONCE(args->sense && - args->sense_len != SCSI_SENSE_BUFFERSIZE)) - return -EINVAL; + if (WARN_ON_ONCE(args->sense && + args->sense_len != SCSI_SENSE_BUFFERSIZE)) + return ERR_PTR(-EINVAL); req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags); if (IS_ERR(req)) - return PTR_ERR(req); + return req; - if (bufflen) { - ret = blk_rq_map_kern(sdev->request_queue, req, - buffer, bufflen, GFP_NOIO); + if (args->bufflen) { + ret = blk_rq_map_kern(sdev->request_queue, req, args->buffer, + args->bufflen, GFP_NOIO); if (ret) goto out; } @@ -232,19 +227,27 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, req->timeout = timeout; req->rq_flags |= RQF_QUIET; - /* - * head injection *required* here otherwise quiesce won't work - */ - blk_execute_rq(req, true); + return req; +out: + blk_mq_free_request(req); + return ERR_PTR(ret); +} + +static int scsi_execute_uninit(struct request *req, + struct scsi_exec_args *args) +{ + struct scsi_cmnd *scmd; + scmd = blk_mq_rq_to_pdu(req); /* * Some devices (USB mass-storage in particular) may transfer * garbage data together with a residue indicating that the data * is invalid. Prevent the garbage from being misinterpreted * and prevent security leaks by zeroing out the excess data. */ - if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen)) - memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len); + if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= args->bufflen)) + memset(args->buffer + args->bufflen - scmd->resid_len, 0, + scmd->resid_len); if (args->resid) *args->resid = scmd->resid_len; @@ -254,14 +257,93 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len, args->sshdr); - ret = scmd->result; - out: + args->result = scmd->result; + + if (args->callback) + args->callback(scmd, args); + + return scmd->result; +} + +/** + * scsi_execute_cmd - insert request and wait for the result + * @sdev: scsi_device + * @cmd: scsi command + * @opf: block layer request cmd_flags + * @buffer: data buffer + * @bufflen: len of buffer + * @timeout: request timeout in HZ + * @retries: number of times to retry request + * @args: Optional args. See struct definition for field descriptions + * + * Returns the scsi_cmnd result field if a command was executed, or a negative + * Linux error code if we didn't get that far. + */ +int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, + blk_opf_t opf, void *buffer, unsigned int bufflen, + int timeout, int retries, + const struct scsi_exec_args *const_args) +{ + struct scsi_exec_args args; + int ret; + struct request *req; + + if (!const_args) + memset(&args, 0, sizeof(struct scsi_exec_args)); + else + args = *const_args; + + args.buffer = buffer; + args.bufflen = bufflen; + + req = scsi_execute_init(sdev, cmd, opf, timeout, retries, &args); + + if (IS_ERR(req)) + return PTR_ERR(req); + + /* + * head injection *required* here otherwise quiesce won't work + */ + blk_execute_rq(req, true); + + ret = scsi_execute_uninit(req, &args); + blk_mq_free_request(req); return ret; } EXPORT_SYMBOL(scsi_execute_cmd); + +static enum rq_end_io_ret scsi_execute_cmd_complete(struct request *req, + blk_status_t ret) +{ + struct scsi_exec_args *args = req->end_io_data; + + scsi_execute_uninit(req, args); + return RQ_END_IO_FREE; +} + +int scsi_execute_cmd_nowait(struct scsi_device *sdev, const unsigned char *cmd, + blk_opf_t opf, int timeout, int retries, + struct scsi_exec_args *args) +{ + struct request *req; + + req = scsi_execute_init(sdev, cmd, opf, timeout, retries, args); + + if (IS_ERR(req)) + return PTR_ERR(req); + + req->end_io = scsi_execute_cmd_complete; + req->end_io_data = args; + + blk_execute_rq_nowait(req, true); + + return 0; +} +EXPORT_SYMBOL(scsi_execute_cmd_nowait); + /* * Wake up the error handler if necessary. Avoid as follows that the error * handler is not woken up if host in-flight requests number == diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 5ec1e71a09de..c80c98b48bc1 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -497,6 +497,10 @@ struct scsi_exec_args { blk_mq_req_flags_t req_flags; /* BLK_MQ_REQ flags */ int scmd_flags; /* SCMD flags */ int *resid; /* residual length */ + void *buffer; /* data buffer */ + unsigned int bufflen; /* buffer length */ + int result; /* scsi layer result */ + void (*callback)(struct scsi_cmnd *scmd, struct scsi_exec_args *args); }; int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, @@ -504,6 +508,10 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd, int timeout, int retries, const struct scsi_exec_args *args); +int scsi_execute_cmd_nowait(struct scsi_device *sdev, const unsigned char *cmd, + blk_opf_t opf, int timeout, int retries, + struct scsi_exec_args *args); + extern void sdev_disable_disk_events(struct scsi_device *sdev); extern void sdev_enable_disk_events(struct scsi_device *sdev); extern int scsi_vpd_lun_id(struct scsi_device *, char *, size_t);